Astronomy

Is it possible that Venus was once a rogue planet?

Is it possible that Venus was once a rogue planet?


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As Venus rotates in clockwise direction, while other planets rotate in anti clockwise direction:

Is it possible that Venus was once a rogue planet?


This is considered very unlikely. It is actually very difficult for things to be captured into orbits. They pick up speed as they fall in towards the larger object, and that's automatically enough speed to carry them back out. Capture either requires dust and gas to slow the body down, or very lucky gravitational interaction with a third object.

This has happened with moons, but the solar system is much more crowded than the galaxy. For something the size of Venus to pass through the solar system at all would be exceedingly rare.

Finally, it is easy to explain the retrograde rotation by other means. This is where the other question that James K mentioned in the comments comes in.


Is it possible that Venus was once a rogue planet? - Astronomy

&ldquoDo you know how many times we have cleared Venus to land?&rdquo (Hendry 27) - The words of an Air Traffic Controller in Detroit

Which of these two objects is Venus and which is an airplane's landing lights? Answer: the bottom one is the airplane. Venus is significantly brighter. (Photo by the author)

If there ever was one object misinterpreted as a UFO, Venus would be at the top of the list. When Venus is at its best, it can spark many UFO reports. Because of this ability to generate UFO reports, Venus is often referred to as the &ldquoqueen of UFOs&rdquo.

As always, it is important to consider one of the best documented sources for investigating UFOs, Allan Hendry&rsquos The UFO investigators handbook, when examining the many sources of UFO reports. Allan mentioned Venus several times in his book. Probably the most applicable paragraph was this one:

Venus continued to attract attention as a &ldquoUFO&rdquo throughout the period of my study. The witness in case 519 likened it to &ldquoMagnesium burning.&rdquo In case 890 and 896, the witnesses said Venus and Jupiter (close together) &ldquobecame so bright that you could hardly look at them&rdquo and &ldquothey hurt your eyes to look at them&rdquo (for two and one half hours). My favorite comment, however, was provided by the FAA at Detroit Metropolitan Airport: &ldquoDo you know how many times we have cleared Venus to land?&rdquo (Hendry 27)

The brightness of Venus can make it a very compelling UFO. In a dark location, I have seen the planet Venus cast faint shadows! Even more deceiving is how Venus appears in thin clouds or unusual atmospheric conditions. It can appear larger and exhibit a halo effect around the planet. Some have seen Venus exhibit a pillar of light due to ice crystals in the air. Venus can be a most attractive source for UFO reports.

Venus photographed through thin clouds using a telephoto lens. (photo by author)

The funny thing about Venus is that it has always been a confusing sight to those not familiar with it. People think that Venus being mistaken as a UFO is a modern phenomena but that is not the case. The "Airship wave" of 1896-7 had plenty of people misidentifying Venus:

Oakland Tribune, November 30, 1896 Page 5

I am sure all the airshipologists of the day would have declared that Professor Burckhalter was a "debunker". In this case, the Professor was correct. Venus had passed superior conjunction in July and was starting to brighten in the western sky. Meanwhile, Mars was near opposition in the east and shining almost as bright as Jupiter. Both were dazzling objects when the sky darkened and could fool an observer into thinking they were seeing something much closer.

Less than a month later, another "debunking" article appeared in a Nevada newspaper:

The Reno Weekly Gazette and Stockman, December 10, 1896 Page 8

This was written by a reporter from the paper, who apparently had some knowledge of astronomy. The "airship wave" of 1897 was about to happen and Venus would play a significant role in fooling many people wanting to see the "airship".

In the spring of 1897, the "airship wave" reached its peak. Buried in all of the reports of people seeing the airship land and move across the sky was this article in the Arizona Republican:

April 3, 1897 edition of Arizona Republican Page 2

At this point, Venus was at greatest brilliancy in the western sky and was a dazzling sight. The planet was up to her usual tricks and the unsuspecting public was taken in by her beauty.

Throughout the decades, Venus continued her little dance misleading observers into thinking she had other intentions. During World War I the new perceptions was that Venus had transformed into an "aeroplane" with a searchlight threatening death and destruction. The hostilities in western Europe had started only a few weeks before when the following article appeared in the August 27, 1914 issue of the Cape Argus:

East London, and particularly Oxford-street, was agog with excitement on Saturday evening. At every corner..were..groups of men, women and children, with eyes goggling, fingers pointing heavenward, and tongues going twenty-four to the dozen as they gaze at an alleged aeroplane in the western heavens. There it was sure enough, visible to all but the blind: at least, a very brilliant light was visible. An aeroplane it was, and of that there was no doubt, for according to various observers it went through all the trick s in an up-to-date airman's repertoire. It looped the loop, squared the circle, spiraled up and spiraled down, volplaned, tangoed to the right and one-stepped to the left, advanced, retired, set to partners, hands down the middle, did everything except..descend in the Recreation Ground of the Market Square. And that searchlight, what did that not do? It waxed and waned, appeared and disappeared, twinkled, winked, the other eye, and signaled in the Morse code in English, French, Dutch, German. and Pitman's shorthand. And all the time it was getting further and further away, though never diminishing in brightness, so that it must have been carried in the tail of the machine.

And oh, the theories that were advanced. Men laid down the law. Ladies became alarmed and wanted to go home and protect their babies from bombs. And it was not until it disappeared behind a heavy bank of clouds in the west that East Londoners breathed a sigh of relief at another happy escape, and went home to dip their pens in the candle and write to the "Daily Dispatch" to describe in letters of fire and words of flames the dastardly attempt to blow up an undefended city.

Judge of the general surprise when the same aeorplane appeared yesterday in about the same place. However, it is safe to predict that it may be looked for again to-night and for several following nights. As a matter of fact what was seen was the evening star, Venus, which happened to be particularly brilliant. A heavy bank of clouds fringed with flying scud and aided by vivid imaginations accounted for all the evolutions and manoeuvres, and we have to hesitate in assuring everyone that they may sleep in peace, for if it depends upon this particular aeroplane, no bombs will be dropped on East London. (Bartholomew and Howard 155-6)

I am sure people in Berlin probably thought the British were also flying an "aeroplane" towards their city as well. The concern of an attack on London by the Germans in France had gotten people looking up in the sky. Just like the "airship" stories from two decades before, people went out looking for an intruder in the sky and found one. Venus, in all her luster, was once again teasing people.

Shortly after Pearl Harbor, many people on the west coast, who were fearful of a Japanese attack, noticed an odd looking light in the western sky. Yes, it was our friend Venus but to these citizens, it appeared to be a plane or flare that might be a threat to their community just like in August 1914.

December 18, 1941 issue of the Brownsville Herald (Texas) Page 1

December 19, 1941 issue of the Wisconsin State Journal Page 10

The scare after Pearl Harbor was enough to give people the perception that Venus could be attacking their homes. All it took was some sort of incentive for people to look for something in the night sky and they found it.

During the end of the Pacific campaign , bomber crews sometimes mistook Venus for a "spotlight airplane/fighter":

Suddenly, over the intercom our right rear gunner yells, "Jap fighter with a powerful spotlight diving on us, one o'clock high!" I look up and see the brilliant light of the diving fighter, just as we had been told about at the briefing. To escape, I push the B-29's nose down, diving and turning to the left. Then right. Now climb. Turn left. Right. Level out. I look up and see another fighter with its brilliant spotlight diving at us. Awaiting the bullets, I cringe and again dive, turn, turn, climb, level out. I look and see another fighter. No, wait. That light doesn't move. Then, finally it dawns on me. The atmospheric conditions were such that they created a layer of air which acted like a huge lens and magnified the light from the planet Venus. Over the intercom, I explain to the crew what the light really was and how the power of suggestion had fooled me. (Kerstner)

The pilots and their crews had been briefed about interceptors with spotlights being used by the Japanese to interfere with their night bombing missions. Venus happened to appear as a bright morning object in the summer of 1947 and proved suitable in the role as this airplane. There are even some reports of B-29 gunners attempting to shoot it down. Of course, they were only successful in wasting a lot of ammunition.

One can read many other stories about people mistaking Venus for "airships", airplanes, or other airborne devices over the years before the word "Flying saucer" or "UFO" became part of the english language. Venus was the "queen of misperception " before she became the "queen of UFOs".

Venus can be seen in the daylight sky when it is very bright. It usually takes some clear skies and the observer has to look in the right place to find it. Because of it being a distant point source, you have to adjust your eyes to spot it. I have seen it at noon when it is at greatest elongation but it required clear skies and knowing just where to look. If somebody does catch sight of it, it can generate a UFO report.

A "Daylight disc"? No, it is Venus at noon when it is at greatest elongation. Photograph was taken using a 300mm lens around midday. (photo by author)

During the Condon study, there was an interesting report of a daylight disc event. Dr. Craig described this event in his book:

The person who originally reported the UFO said it had caused his 'Magnetic UFO detector' to sound the alarm, and when he went outside to look, sure enough, there was a UFO straight overhead. He had pointed out this distant bright object, high in the sky, when the staff team arrived about an hour later. Mary Lou phoned the UFO officer at one of Air Force bases in the region to learn if he had knowledge of an unidentified object then in the sky. She was most indignant when it was suggested to her that they were 'probably chasing Venus,' and she commented upon the nerve of anyone who would suggest a PH.D. scientists would be chasing a planet without recognizing it. Mary Lou's indignation must have mellowed considerably the next day when he arrived at the office with figures which showed the light had moved westward at 15 degrees per hour, and expressed the suspicion that the observed light must have been an astronomical object. The coordinates of Venus matched those of the observed bright light. While this may have left some staff members slightly embarrassed, it was a valuable lesson to those who were to conduct field investigations of UFO reports later. (Craig 38-39)

It is very interesting how these scientists could be fooled by such an event. It took a lot of careful calculations to reveal they were just observing Venus in daylight. How many "daylight discs" can be traced to Venus and would a UFOlogist understand it is possible that Venus can be seen in daylight? Venus, even in daylight, can be the source of a UFO report.

Georgia 1967: A case history often ignored

The Condon report listed several events related to Venus. One in particular stands out because Venus appeared to set off a &ldquowave&rdquo of sightings that involved numerous experienced police officers, who are supposedly considered &ldquoreliable and credible&rdquo observers. The entire series of events transpired over several days and involved some of the most common issues associated with stars and planets being misperceived as UFOs:

  1. A radar contact was attributed to the UFO. A pilot, with 4,000 hours of flying time, attempted to intercept the UFO with his Cessna. On the ground the policemen saw the aircraft fly past the UFO several times. When they directed the pilot towards the UFO, the pilot attempted to pursue it. From the ground, it appeared that the pilot flew under the UFO and ignored it. However, in the air the pilot was following the UFO. To him, it appeared to move away when he attempted to pursue it and then came back when he turned away.
  2. Various shapes and sizes were given. &ldquoFootball shaped light&rdquo, &ldquoBig as the moon&rdquo, &ldquoappeared to be a star&rdquo, &ldquoround&rdquo, &ldquothe shape of a giant four-leaf clover&rdquo, &ldquoA piece of floating tin foil&rdquo, &ldquoa yellow rectangle-shaped object&rdquo, &ldquosphere shaped object approximately 25-feet in diameter&rdquo, etc. (Condon 370-373)
  3. The objects always disappeared after sunrise
  4. Police officers attempted to pursue the UFO in their vehicles on more than one occasion. In one instance, the police attempted a high-speed pursuit. According to the report:

It was a good distance in front of us, pulling away, so we turned around to come back to town. The object turned on us and followed. It gained on us and was going about 75 mph. After the object caught up with us, it pulled into the sky, emitting a beam of bluish light that illuminated the roadway. (Condon 373)

In all these case, the police officers and pilot were chasing the planets Venus and Jupiter, which had risen in the east and were very bright.

The sky at 4:30 AM from Georgia on 20 October 1967. (Orion's "The Sky" program)

Dr. Craig explains some of the problems associated with chasing an object like Venus in a moving vehicle:

The apparent pursuit of moving vehicles, or flight from them, is characteristic of any distant object which is imagined to be close to the observer. Because of the object's great distance, it remains essentially the same direction from the observer as the observer moves. Because of the object's great distance, it remains essentially the same direction from the observer as the observer moves. Compared with trees or terrain nearby which change in direction as the observer moves past them, the object, retaining a constant direction, does seem to be moving the same speed and direction as any observer who thinks it no more distant than the reference terrain. It is a characteristic of this "pursuit" that the object stops when the observer stops, resumes its motion as the observer resumes motion, goes the opposite direction when the observer reverses direction, and travels at whatever speed the observer happens to travel. (Craig 47)

Venus looking through a car window going down a road. It appears to be hovering just beyond or above the trees in the distance. (Photo by the author)

Dr. Jay Allan Hynek, one of UFOlogy&rsquos leading scientists, would state the following about this case:

It is a fantastic example of how persuasive the planet Venus can be as a nonscreened UFO. Police officers in 11 counties were "taken in" by this planet. It is a case of particular value to psychologists and, one is tempted to say, to those responsible for hiring policemen. (Hynek 205)

Hynek seems to imply by this that these police officers were not very trustworthy. However, it did not mean that police officers are not reliable officers of the law. It only meant that police officers can make mistakes in perception as easily as any other profession. This is a lesson many UFOlogists would choose to ignore time and time again.

Solar Eclipse 1991 : Bad astronomy in Mexico

In 1991, the solar eclipse gave Venus another chance to play her role as UFO spoiler. For some it was a sign in the heavens when this brilliant object appeared just before totality in Mexico. Many recorded Venus with their video camera and proclaimed it a UFO. Over enhancing of the videos made Venus appear to look like a craft of some kind. Enter the usual snake-oil salesmen of UFOlogy who peddled these videos of UFOs and created a myth that there was a UFO invasion underway. It is all chronicled in my article at this link. The one question I ask about this &ldquoUFO&rdquo is why did&rsquot any astronomers notice it? There were hundreds, if not thousands, of amateur and professional astronomers in Mexico City alone. Is it possible that they realized it was Venus and not a UFO?

Ravenna Ohio 1966: Spaur chase

This is one of UFOlogy&rsquos classic cases and inspired the scene in Close Encounters of the third kind, where a police officer chased an alien spaceship over a cliffside. A basic synopsis of the case is that Policemen Dale Spaur and his partner Wilbur Neff chased a UFO at high speed over eastern Oho and into Pennsylvania. They were eventually joined in pursuit by another officer, Wayne Huston. By the time they reached Pennsylvania, they ran into another police officer, Frank Panzanella, who had been observing the UFO for some time towards the east. The UFO then gained altitude and eventually disappeared.

UFOlogists scoff at the idea that, as the USAF and skeptics suggest, the main culprit was the planet Venus. The Spaur chase argument against Venus had to do with a few key points:

  1. Initially, Spaur and Neff saw the UFO pass overhead and illuminate the highway. This is something Venus could not do. The USAF contends that the Echo satellite, which could be very bright, is what was seen as passing overhead. Skeptic Robert Sheaffer suggests that it could have been a bright meteor. In either case, it is not unreasonable to suggest that either stimulus could have triggered the event.
  2. Officer Huston also supposedly saw the UFO pass overhead at about an 800 foot altitude shortly before Spaur and Neff&rsquos car came by. He then joined in on the chase. Did Huston see a bright meteor and thought it was the UFO being pursued by Spaur and Neff? After all, he had heard about the chase and he was looking for a UFO. If he saw a bright meteor going in the correct direction it could explain this part of the sighting.
  3. A drawing by Spaur made six days later showing the positions of the moon relative to the UFO. The UFO is on the left side of the moon, while Venus was on the upper right.
  4. On numerous occasions, the UFO chose to "wait" so the officers could catch up. According to UFO investigator William Wietzel:

At Canfield, or just outside the city, the UFO turned south. It seemed to "wait" for Spaur and Neff to catch up. It had done this, I forgot to mention, at Deerfield. It did again near Columbiana, where I65 intersects 14-46, and may have at Berlin Center (intersection of 534 and 14). (Wietzel)

However, UFOlogists tend to ignore some important points that indicate it could have been Venus:

  1. Officer Panzanella in Conway Pennsylvania reports he saw the UFO starting around 5:20 AM to the east of his location and observed it for some time. When Spaur, Neff, and Huston showed up they also identified the same object as the UFO they pursued. The funny thing is that Panzanella stated the object was always in the east for him and Huston had stated the object had passed over him at 5:30 AM and he was located much farther to the west in Ohio! One would think if this were an object traveling around 100 mph, Panzanella would have seen that the object moved from the west towards the east. Failing to mention this observation indicates something was wrong with the story about a high speed chase.
  2. There are numerous non-testimonies to consider. According to Wietzel, the officers passed through a traffic light in Rochester, PA, where there was a volkswagon and some trucks. None of these individuals reported seeing a UFO pass through the intersection or nearby. One would also expect that some other cars on the road at the time would have noticed some huge bright object speeding past them or near their position. Again, there is a lack of any such reports. It appears the only people who reported the object speeding over the road were officers Neff, Spaur and Huston, who were pursuing it.
  3. Spaur's six-day old sketch of the moon and the UFO is confusing. He shows a bright object just to the right of the moon, which UFOlogists state is the planet Venus. However, the position of Venus was much higher in the sky and not next to the moon. However, at the end of the event he claimed the UFO "shot upwards" in a position that seems to above the moon and towards the left. This is more in line with where Venus was located (although Venus was more to the right of the moon). Is it possible he originally felt it was closer to the moon during the chase and when they exited their vehicles, the angular distance was greater and they convinced themselves, the UFO must have "shot upwards"? Is it also possible that the diurnal motion of the planet gave the impression of rising motion? Exactly how accurate is the sketch in relation to the moon as far as angular separation and location relative to the moon? Is it possible, at the time of his drawing, he was aware of people suggesting it could have been Venus and adjusted his drawing to prevent embarrassment?
  4. Another important point to note was the witnesses stated they saw an airliner pass near the UFO. According to them, somebody on the plane should have seen the UFO. The lack of any reports indicates they saw no UFO. This was just like the Georiga 1967 case, where police officers claimed the pilot flew past and under the UFO without recognizing it.
  5. One of the big keys that Venus was possibly involved has to do with what happened to the UFO at the end of the whole event. It dimmed as the sun rose and eventually vanished! This is the same way one would expect for Venus to fade away after sunrise.

The sky at 0530 on 17 April 1966 from Ohio (Orion's "The Sky" program)

Hynek takes great pains to criticize the USAF explanation in his book, The UFO Experience. If you recall, this was the same book where he claimed the Georgia case in 1967 was an excellent example of Venus misperceived as a UFO and people should learn from it. Apparently, Hynek did not see the similarities between the two cases. One has to wonder why Hynek would consider one case evidence for UFOs and the other as an example of how the selection of police officers needs to be examined. Is it too much of a stretch that Officer Spaur and his companions did the same thing as those in the Georgia case? In the Georgia case, one of the police officers was an eleven year veteran. What makes Spaur any more reliable than that officer?

Looking at the Georgia 1967 events, the events of April 17, 1966 appear very similar. We have the apparent motion of the object away from the chasing police vehicles, the "waiting" of the UFO while the cars navigated traffic, the inability of aircraft to recognize the UFO, and the dimming/disappearance of the UFO at sunrise. If it wasn't Venus, the UFO sure wanted to act like it.

Jimmy Carter 1969: A Presidential UFO

The Jimmy Carter UFO case is considered a landmark case only because he would eventually become President of the United States. What UFOlogists fail to mention is that Jimmy Carter reported his UFO sighting in 1973, while the actual event occurred in January 1969. Another issue never mentioned is that Carter could not even remember the correct date and put October 1969. It took some basic investigative work by Robert Sheaffer to correctly pinpoint the date to January 6, 1969. This is something UFOlogists did not do. It was also Robert Sheaffer who recognized that the lovely planet Venus was present at this event.

According to Carter he was to address the Lions Club at Leary, Georgia. Prior to the meeting, his attention was focused on a bright object in the western sky. He pointed it out to about a dozen other individuals around him and they observed the object before the meeting began. Then, they all simply went inside and forgot all about it. Carter did not mention it in the meeting and there was no great desire to figure out what ti was. It was not mentioned in the papers and nobody seemed to think much about the event. That is, until Carter became President of the United States.

Carter's key points in his report were location in the sky, approximate time of observation, and apparent angular size:

Location in sky: "Appeared from West--About 30 [degrees] up."

Apparent Angular size: "About the same as moon, maybe a little smaller. Varied from brighter/larger than planet to apparent size of moon." (Carter)

Sheaffer's work identified the correct date of Carter's sighting as January 6, 1969 based on the actual date of the meeting. At 7:15 PM, the planet Venus was located in the west-southwest and at an angle of elevation of roughly 24 degrees. This is the very close to the location Carter describes.

The sky for Carter that evening. (Orion's "The Sky" program)

The angular size described seems a bit large but that does not seem to be too much of an issue when you look at the case histories surrounding Venus observations as a UFO. The Georgia 1967 case is a good example where people reported large angular sizes for Venus and Jupiter. Additionally, Allan Hendry describes one case of his, where a witness stated the UFO he saw changed in &ldquoapparent size fluctuated from &lsquostar&rsquo to &lsquoFull moon&rsquo&rdquo (Hendry 95). Hendry then comments, &ldquoRefers to a star seen for one and one half hours. Compare with President Carters report of a &ldquoUFO&rdquo (Hendry 95). Therefore, any argument about the angular size being a reason to dismiss Venus as the source of the report is ignoring UFO case histories.

I have also read that some UFOlogists state Carter should have known where Venus was because he was a Naval officer and a farmer. I am unaware what these two qualfications have with knowing the position of Venus in the sky at a particular time of year. Looking at all the case histories presented so far, we have had all sorts of occupations misidentifying Venus. Therefore, being an ex-Naval officer or a farmer would not make him any more immune to misperception than the others.

The Carter case has become something of a "sacred cow" in UFOlogy. It is often presented by various groups as evidence that even Presidents see UFOs. However, to consider the Carter case something other than Venus is just ignoring anything that has been learned about UFO reports over the past sixty years.

Malmstrom AFB 1975: Airmen are not astronomers

Recent correspondence brought this case to my attention. It involves several UFO sightings at Malmstrom AFB, where excited security guards made UFO reports about a series of objects in the skies one November morning. One UFO stands out:

7 Nov 75 (1035Z) Received a call from the 341st Strategic Air Command Post (SAC CP), saying that the following missile locations reported seeing a large red to orange to yellow object: M-1, L-3, LIMA, and L-6. The general object location would be south of Moore, Montana and 20 miles east of Buffalo, Montana (authors note: From what I determined this direction is to the SE of site M-1 and NE of L-3 and L-6). Commander Deputer (sic) for Operations (DO) informed.

7 Nov 75 (1203Z) SAC advised that the LCF at Harlowton, Montana, observed an object which emitted a light which illuminated the site driveway. (Fawcett and Greenwood 29)

That morning the planet Venus had risen in the East by 1035Z and a bright planet Mars (magnitude -1) was overhead. The geographical position at 1035Z in relation to the missile sites of the "red to orange to yellow object" does not exactly agree with the position of Venus. However, it is important to note that the log entry states the position east of Buffalo is a "general object location" based on reports they received from airmen, who may have not be exactly precise in their directions. Still the "general direction" reported was in an east, which is where Venus was rising.

The view towards the east from Malmstrom AFB at 1035Z on 7 November 1975. (Orion's "The Sky" program)

Things get a bit more clear in this log entry:

7 Nov 75 (1319Z) SAC advised K-1 says very bright object to their east is now southeast of them and they are looking at it with 10x50 binoculars. Object seems to have lights (several) on it, but no distinct pattern. The orange/gold object overhead also seems to have lights on it. SAC also advised female civilian reports having seen an object bearing south of her position six miles west of Lewistown. (Fawcett and Greenwood 29)

By 1319Z, Venus had shifted towards the SE and was significantly higher in the sky just like the log entry describes for K-1. K-1 was to the southwest of the other sites described. The fact they reported the object as being to the east indicates the "general object location" described at 1035Z is probably not accurate because K-1 would have stated they saw the object to the northeast and not to the east. Additionally, for it to move to the southeast of K-1, L-3 and L-6 would have reported the object moving towards the south and possibly flying over them. It now appears that the UFO being described by all the sites are of Venus.

The astronomical nature of these UFOs is confirmed in the following log entries:

7 Nov 75 (1355Z) K-1 and L-1 report that as the sun rises, so do the objects they have visual.

7 Nov 75 (1429) From SAC CP: As the sun rose, the UFOs disappeared. Commander and DO notified. (Fawcett and Greenwood 29)

The second entry should have been a big red flag that these were astronomical objects. Unless somebody is suggesting that these UFOs are vampires that vanish when the sun comes up, then Venus is probably one of the principal sources for this event.

United Airlines 94: Pilot error?

Probably one of the most interesting cases presented recently has to be the one of pilot Neil Daniels, who was an airline pilot flying for United Airlines in 1977. This case came to my attention in 1997, when I was reading the Sturrock panel report:

The DC-10 airplane was under the control of autopilot system #2 and was flying at 37,000 feet altitude. The entire sky was dark and clear ahead and above the airplane, except for a partial under cast with small clouds extending to about 20 miles ahead. The aircraft was flying at an indicated air speed of 275 knots (true air speed 530 knots). The aircraft was about half way between Buffalo and Albany, and had just changed from contact with the "FROM" VOR (Very-High-Frequency Omnidirectional Bearing) signal emanating from Buffalo to the "TO" signal from Albany. The aircraft was just south of Syracuse, New York.

Suddenly and unexpectedly, the airplane began to turn to the left, making a 15 degree bank. Within a few seconds, the First Officer and the Captain looked to the left side of their plane and saw an extremely bright white light at about their own altitude. Subsequently, the Flight Engineer also looked and saw the light source. It appeared to be perfectly round and its apparent diameter was about 3 degrees of arc. However, the Captain estimated the object to be about 1,000 yards away and to be about 100 feet in size, that corresponds to an angular size of 2 degrees. "Its intensity was remarkable &mdash about the intensity of a flashbulb," he remarked. Boston ATC radioed to ask "United 94, where are you going?" The Captain replied "Well, let me figure this out. I will let you know." He then noticed that the three cockpit compasses (that use sensors in different parts of the plane) were all giving different readings. At this point, the Copilot turned off the autopilot and took manual control of the airplane.

Based upon the fact that the object did not move laterally in the cockpit window during the 45 degree left heading change and from knowledge of the turn radius of this airplane at its stated velocity, Haines calculated the approximate distance to the object to be about 10 nautical miles. If the pilot's angular size estimate for the object is accurate, this suggests that the light source was about 2100 feet across. The object appeared to stay with the airplane for 4 to 5 minutes, after which it departed very rapidly, disappearing within about 15 seconds behind them to the west. The Captain asked ATC if they had any radar traffic in that area and received a negative reply. (Sturrock 86-7)

The scientist presenting the case was Dr. Richard Haines, who has spent many years chasing down UFO cases associated with aircraft. However, we are not presented any data regarding an incident report or maintenance records regarding the flight. Haines indicates that the UFO must have affected the port side gyrocompass more than the starboard causing the aircraft to bank to the port in a northerly direction. What is confusing with this theory is that the UFO only became visible when the aircraft began its bank to the northeast because it was in the west. So, how could the UFO affect one side of the plane if it was directly behind an eastern bound aircraft? We are left with this quandary. Perhaps this is why the panel of scientists reviewing the case stated:

In responding to this presentation, the panel took the position that evidence of interference with aircraft equipment is interesting but, in the absence of corroborative data from flight recorders and other mechanical or electrical recording equipment, the evidence presented must be regarded as anecdotal. It is quite possible that the persons making the report summarized above did indeed see unusual and striking phenomena. It does appear that the airplane departed from its normal flight path, but this could have happened for a variety of reasons. As with reports related to other categories of physical evidence, the evidence summarized in this section should be regarded as suggestive but far from sufficient to establish any actual physical linkage between the reported luminous phenomenon and the airplane's flight deviation. In order to improve our understanding of these phenomena, it will be necessary to establish more definite facts from the case work. To this end, there should be strong efforts to quantify the observations and to obtain multiple measurements of the same event, and investigators should bring a critical attitude to the compilation and analysis of the data. (Sturrock 88)

So what are some alternative explanations for what happened that night. One is "pilot error". The possibility exists simply that the crew goofed and caused the course deviation. I am no expert in autopilots but it seems possible that the switching of VOR stations might have affected the navigation system and autopilot. After all, the plane changed course shortly after they had changed the VOR station. I am sure there are other potential problems that could produce the course deviation as well. Something as simple as a poor solder joint on a circuit board might cause an intermittent connection and cause instrumentation to fail. In this scenario, the problem could disappear as quickly as it came. Did this particular plane ever demonstrate the problem before or after this case? Without any additional information, it is hard to determine what really transpired. It seems more plausible that a pilot mistake or equipment malfunction caused the course deviation than an alien spaceship playing with the gyrocompasses!

What about the UFO? The planet Venus was in the west and set from Syracuse at sea level at 2106 EST. For a plane at 37,000 feet, the set time was about 2123 according to "Starry Night backyard". A check of weather reports indicated that a low pressure system made it into the region on the following day increasing the likelihood that clouds in the west may have played a role. Any distant horizon clouds could cause it to "rapidly disappear" before it had actually set. It seems Venus is a good candidate for the UFO reported by Daniels.

The western sky from 37,000 feet above Syracuse NY on March 12, 1977 at 2105 EST.

The planet in Taurus near the Pleiades is Jupiter, another bright planet. (From Starry Night Backyard program)

I found it interesting that Haines never mentioned the word "Venus" in his presentation (or at least it was never recorded as being discussed). Wouldn't a scientist investigating a UFO case look at one of the greatest sources of UFOs first? Maybe a more "critical attitude" towards examining this case could have resolved this. Instead the "Neil Daniels" case has now entered UFO folklore. It is even part of the "disclosure project" presentation.

While many UFO proponents will proclaim this case an example of UFO interfering with the operations of an aircraft, it appears there is a better explanation. The probablility of pilot/equipment error coupled with a sighting of Venus seems more likely than a UFO trying to manipulate the flight of a passenger airliner for no good reason.

The sirens in mythology lured unsuspecting sailors to their doom through their enchanting music. The same can be said for Venus with UFO reports. She lures unsuspecting observers by the beautiful light she reflects from the sun. Her power of suggestion is so great that she can convince people that she is something close and exotic. Too bad she does not have the same effect on UFO investigators who are looking for a potential source to a UFO report. To them, Venus is something ugly to be scorned. Only skeptics or the USAF will use her to explain a case. The truth of the matter is that Venus, despite the protestations of UFOlogists, is a major source of UFO reports and has to be seriously considered as the source if it were in the sky at the time of the report. Failure to consider her is avoiding the lessons of the past.

Batholomew, Robert E. and George S. Howard. UFOs and Alien contact: Two centuries of mystery. Amherst, NY: Prometheus books, 1998.

Carter, Jimmy. International UFO bureau sighting report form. Available WWW: http://www.nicap.org/waves/CarterSightingRptOct1969.pdf

Condon, Edward U., et al., eds. Scientific Study of Unidentified Flying Objects. New York: Bantam, 1968.

Craig, Roy. UFOs: An Insider's View of the Offical Quest for Evidence. Denton: University of North Texas Press, 1995.

Fawcett, Larry and Barry J. Greenwood. The UFO cover-up: What the government won't say. New York: Fireside of Simon and Shuster, inc. 1992.

Hendry, Allan. The UFO Investigators Handbook. London: Sphere Books Ltd. 1980.


Was Venus ever within the habitable zone of our Sun?

It is a known fact that main sequence stars increase their luminosity over time, as helium accumulates in their cores.

Even though our own sun will be around for

5 billion more years, it will have gotten bright enough 500 million years from now to have boiled away our oceans.

So what if we turn back the clock? Was there a time, say, 3 billion years ago, when the current orbit of Venus would've been within the habitable zone? Would it have been in the habitable zone at the time (considering how chaotic the early solar system was, it's likely that all of the planets moved at least a little bit, IIRC)? Is it still within the habitable zone now?

EDIT: Torn between "astronomy" and "planetary science" flairs.

Venus is actually in the habitable zone, however its thick atmosphere prevents temperatures for life as we know it to exist. While studying astronomy, one of the things a professor pointed out was that if Mars and Venus were to be swapped, both would likely be able support life.

Wouldn't Mars's extremely thin atmosphere likely have been blasted away by solar wind if its orbit was swapped with Venus's?

Man, could you imagine living in a solar system with 3 habitable planets. The wars.

I heard that before we realised how hellish Venus's atmosphere is some people theories that it might be largely a lush jungle of some kind.

Oh wow - that's interesting! Got a source by any chance?

Venus is actually in the habitable zone

There are a few working definitions of the habitable zone, but I don't think this is true in any of them. Even the most optimistic estimates put the inner edge at 0.75AU. The most often used versions are based on global climate models to investigate what happens if the Earth is moved closer/further from the Sun. In that case, the current inner boundary is at 0.95AU (the old estimate by Kasting et al) to 0.99AU (an updated version by Kopparapu et al). Venus is interior to all these estimates at 0.72AU.

I was on a paper a few years back (pdf warning) where we extrapolated habitable zone boundaries in time to cover solar system and extrasolar system planets, and we put Venus in the Sun's Habitable Zone for its first 1.3 billion years.

There is exceptionally good evidence that Venus once had many oceans' worth of water.

One of the things we can measure is the enrichment of deuterium (heavy hydrogen) relative to hydrogen. We believe the primordial abundance was 1 deuterium atom for every 50,000 regular hydrogen atoms this is also the abundance we observe in places like Jupiter.

On Venus, though, this abundance is more like 1 deuterium atom for every 60 hydrogen atoms, very different than primordial values. We believe that Venus likely did start out with that 1-in-50,000 deuterium abundance, but regular hydrogen being much lighter than deuterium had a much easier time escaping the planet, enhancing the abundance of deuterium relative to hydrogen.

When you work the math backwards, the amount of hydrogen the planet once had was enormous, and the only obvious solution to that was that Venus once had massive amounts of water (H*2*O) that subsequently evaporated, got split by UV light into its constituent atoms, and the hydrogen subsequently escaped the planet. The oxygen, meanwhile, appears to have bonded with the surface we see tons of oxidized minerals on the surface.

It's still unclear if the original water was in liquid form (rather than water vapor or hydrated minerals), but it's very possible that Venus was once habitable.


Howdy, er, neighbor – mind if we join you? Potential sign of life spotted in Venus's atmosphere

“If the JCMT signal were from phosphine in the mesosphere, then to account for the strength of the signal and the compound’s sub-second lifetime at that altitude, phosphine would have to be delivered to the mesosphere at about 100 times the rate that oxygen is pumped into Earth’s atmosphere by photosynthesis,” said Victoria Meadows, co-author of the Washington paper and professor of astronomy at the university.

To answer the question once and for all, scientists need to send a probe to Venus to directly sample the chemical composition of its atmosphere.

“There may be phosphine in Venus’s atmosphere,” Akins told us. "The real question is how much phosphine there is, if any. The exciting part about the original claim was that the amount of phosphine detected was beyond what could be explained by our current understanding of Venus’s atmospheric chemistry, hence the need for something else like life to generate that much of it.

“Our interpretation of the observations is that this much phosphine isn’t present at Venus. If phosphine is present in Venus’s atmosphere, there would be far less of it, which wouldn’t be nearly as exciting.” ®


Venus discovery: Major finding reveals planet is not as dead as thought

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NASA simulates what sunsets looks like on other planets

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A bombshell new study has revealed there is still much activity happening on and beneath the surface of Venus, the planet one step closer to the Sun. Astronomers had believed that Venus was once Earth-like, complete with an atmosphere and oceans.

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However, over billions of years, it lost its atmosphere and researchers theorised all geological features on Venus virtually came to a stop.

New research, though, suggests the small planet is alive and kicking after astronomers discovered the presence of 37 volcanic structures on Venus that appear to have been recently active &ndash and probably still are today.

The study, published in the journal Nature Geoscience, focussed on ring-like structures called coronae which are caused by the swelling of hot rock beneath the surface.

Volcanoes and earthquakes would prove that the planet is still active as they are caused by processes in a planet's core, which in Venus's case, much like Earth, is still swashing magma.

Venus discovery: Major finding reveals planet is not as dead as thought (Image: GETTY)

A CGI of Venus' surface (Image: GETTY)

Study co-author Laurent Montési, a professor of geology at the University of Maryland, said: "This is the first time we are able to point to specific structures and say, 'Look, this is not an ancient volcano but one that is active today &mdash dormant, perhaps, but not dead.

"This study significantly changes the view of Venus from a mostly inactive planet to one whose interior is still churning and can feed many active volcanoes."

The researchers, led by geophysicist Anna Gülcher of ETH Zürich in Switzerland, used computer simulations coupled with data by spacecraft such as NASA's Magellan probe, which orbited the planet from 1990 to 1994, to come up with the most realistic situation for Venus' current state.

Ms Gülcher said: "The improved degree of realism in these models over previous studies makes it possible to identify several stages in corona evolution and define diagnostic geological features present only at currently active coronae.

Venus: Facts and figures (Image: EXPRESS)

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"We are able to tell that at least 37 coronae have been very recently active."

Despite the planet not being as dead as astronomers thought, it is still unlikely that any life would be able to live there.

Temperatures on Venus exceed 460 degrees celsius thanks to the tick, poisonous atmosphere that is full of carbon dioxide leading to an extreme greenhouse gas effect.

At that temperature, which is hotter than Mercury, the closest planet to the Sun, there is no liquid on Venus of any kind, making the prospect of life impossible by current scientific understanding.


Pedra Do Inga

Pedra do Inga easily ranks among the most mysterious archaeological sites of the past century. This is a monument that differs from the previous three ancient star maps we discussed because it is so much more. Besides the distinctive astronomical features, Pedra do Inga has another 400 engravings that illustrate animals, foods, humanoids, even rituals, and unknown symbols.

Now, experts believe that some of the symbols on the massive monument form a solar calendar while others are illustrations of constellations. Very few of these engravings have been deciphered but experts believe they have found Orion and Cygnus, as well as the Milky Way.

There are hundreds of engravings on Pedra do Inga and many have astronomical meanings. Credit: IgorSuassuna / Pixabay

There are a couple of incredible facts about Pedra do Inga that we should mention. First, experts cannot date the monument. They know that the stone base is 6000 years old and more. As for the engravings, they could be several hundred or several thousand years old.

Even more interesting is the fact that experts found Egyptian and Sumerian symbols engraved on Pedra do Inga. Does this mean that the monument is thousands of years old and ancient civilizations from South America and Mesopotamia were in contact? Or was Pedra do Inga created recently and these symbols were simply put there to confuse us?

Ancient astronomers were obviously better at their job than historians ever believed. We find proof of their achievements year after year. So, it is obvious that astronomy is as old as human civilization. But what if it is even older?

For example, recent research on 40,000-year-old cave paintings, previously believed to be illustrations of animals, suggested that they were actually constellations and stars. What if astronomy predates even the earliest human civilizations?

It is more than clear that the ancients had a much better view of the sky than we do even without powerful tools like telescopes. But how could they understand the night sky to such an extent? It is not possible that they simply copied what they saw because there are clear explanations of each object on these ancient star maps.

Were these star charts created by the cultures we believe or were there more advanced ancient civilizations that made these observations? This is a commonly discussed problem in the community although many experts prefer to stay away from such “controversial” theories. But is there a better explanation at this point?


I need to finish the paper and consider the thesis but at best the author misinterprets the initial quote.

Scientific discoveries require careful preparation. The NASA team discovered good data on Venus because they designed and prepared their systems to collect atmospheric data. While Venus might be considered a calibration run for MESSENGER before testing Mercury, 'luck' in the sense of 'blind chance' was not a major factor in this discovery.

Rescher writes about plans and scripts that long term experiments require adaptation to conditions. Perhaps serendipity would be a kinder, more meaningful description.

2 bars of nitrogen so that was already known. The surprise was that N2 is more abundant above the clouds than below. The prevailing assumption was that it was well-mixed, but the new data suggests the two layers don't mix well.

So it's not new evidence for a Cataclysm - there's other lines of evidence for that - but that we don't understand how atmospheres work quite as well as we thought. The global resurfacing of Venus was the Cataclysm and our present best guess places it roughly the same time that Earth was going through near global Glaciations. Were they related? The quasi-coincidence in time makes one wonder.

Summary:: Is this evidence that Venus originally had a nitrogen atmosphere and the present amount of CO2 was released by some cataclysm?

Has MESSENGER found evidence that Venus originally had a nitrogen atmosphere, and might have been more habitable, and the present amount of CO2 was released by some cataclysm afterwards?

The consensus view (though it is challenged by some) is that the absence of plate tectonics led to a gobal resurfacing of Venus between 600 mya and 1000 mya. This accounts for the relatively "young" surface. However, this cataclysm is not associated with the predominantly carbon dioxide atmosphere of the planet. That is a consequence of the outgassing of planet in its later stages of formation, following core formation and the onset of crystallisation of the magma ocean.

That primordial atmosphere was primarily one of CO 2 , with one or two bars each of water and nitrogen. The subsequent loss of water (avoided by the Earth because it was further from the sun and had a magnetic field) not only left a predominantly CO 2 atmosphere, but eliminated the possibility of capturing that CO 2 in minerals, as was the case on the Earth. (The Earth has about 90 bars of CO 2 locked up in crustal minerals.) At the same time it prevented the development of plate tectonics, which led in turn to the global resurfacing mentioned by qraal.

Those interested in the development of the atmospheres of the terrestrial planets would find Origin and evolution of the atmospheres of early Venus, Earth and Mars an excellent read. It demonstrates the great insights that can be had from the determination of isotope ratios and a knowledge of their partitioning by various processes (and thus reveals what processes were at work). It also gives a good summary of current views on such matters of planetary formation as core formation and timing of the loss of nebula gas. I strongly recommend it.


Will the government UFO report show we’re not alone?

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The US government report on UFOs could give us answers—or not, astronomer Nick Suntzeff says.

The government report on unidentified flying objects is coming soon.

Texas A&M University astronomer Suntzeff has been involved with space research for 30 years and spent 20 years in Chile, where he helped co-discover dark matter.

Here, Suntzeff offers his thoughts about UFOs and whether or not we are alone in the universe:

What can we expect from the government’s official UFO report?

I have no idea what the report will say, but I doubt they have any evidence where a UAP (Unidentified Aerial Phenomenon, previously called a UFO) is clearly resolved. For starters, have you ever noticed that UAP images and videos are usually out of focus?

In the recent videos that are now getting a lot of attention called FLIR1, Gimbal, Triangle, and GoFast, for instance, let’s consider the triangular UFO. In the video you can also see other objects that are triangles. Are these sister UFOs? No. What this means is that the camera was out of focus and the camera pupil (shutter) was triangular. One person has measured the positions of the faint triangles (and one bright one) and shown that they are at the positions of the stars near the constellation Taurus and the planet Jupiter. Also, this UFO blinks in the same way a commercial aircraft does. It was taken off the coast of Los Angeles where there are lots of air traffic. It is an out-of-focus video taken with an infrared camera.

This is one example of an explanation that fits the data. Now, why did the Navy not provide this explanation? They should have asked an astronomer before releasing the video because they could have quickly shown that this an out of focus image.

So does that mean the UFOs are not real?

Well, you can often debunk one story, but you will then get another story and someone will say, “okay, but explain this one.”

In one video, a pilot says the UFO resembled a large Tic Tac mint and that it was defying the laws of physics over the ocean and moving fast. The problem here is that we don’t know how far away it was. If it was high above the ocean, then the apparent motion is likely due to the airplane and not the object.

This is called parallax. You can often find answers like this, and so on.

So I am not optimistic that we will be shown extraordinary evidence where there is no natural explanation for what is seen.

So you are saying that you can rule out most UFO sightings as something else and not a UFO?

There are often simple, but boring answers. For example, the most common UFO is the planet Venus. Once I got a phone call from an excited person who was telling me they can see a UFO right now. It is moving back and forth, and sometimes it suddenly comes closer and then moves away. I asked them if they could still see it. Yes! So I drove down to the parking lot and there was a group of people bunched together pointing up to the sky. I went over there and asked them to show me where it is. I look up there, and it is Venus. I tell them it is Venus. I look at it and it is not moving. It was twinkling a bit but otherwise, nothing unusual. As we looked, they admitted it was not moving, but I was assured that it was before I got there.

Many people are convinced that these UFOs are visitors from another planet, that they have been monitoring the Earth for decades and they are real. If true, it would be perhaps the biggest story of all time. Is it possible?

I can’t rule out we have visitors from other planets. But we need clear evidence. We need a clear photo, for instance. So far, we do not have such evidence.

Note that many reports say that the UFO object was a certain size and moving at a certain speed. Now, if you don’t know what the object is, you can’t know how far away it is, or how big it is. Anyone who says they know the size (unless it landed and left a mark) is, well, not understanding simple optics. So once again, we need clearer proof. I have seen lots of weird things in the sky—very weird things—but I can always explain them.

As for intelligent life—in a way it is a strange question. As the great physicist Enrico Fermi was claimed to have says, “Well, where are they?” That is, if there is intelligent life, why don’t we see it with our telescopes, or see evidence here on Earth of visitations? Astronomers are always looking for life elsewhere in the universe.

Any shred of truth to the long-held rumors that the government has been hiding pieces of crashed UFOs and perhaps even bodies?

If they do, this is the best kept secret ever. Our government is not great at keeping secrets, and this one would be a doozy. No, I don’t believe there is any physical evidence. I don’t think intelligent civilizations could travel the thousands of light years to the earth, and then crash their spacecraft. If they can travel that distance, I seriously doubt they would be this careless.

It seems like the scientific community has always been more than a little reluctant to talk about UFOs. Why is that?

We are not reluctant to talk about it. There are a number of astronomers actively looking for signs of intelligent life out there. It is a real field in astronomy. The problem is that one cannot get government funding to study UFOs. So those astronomers look to the private sector to do the studies. A very close friend of mine, now retired, built his own observatory and is searching for intelligent signals. He got this funded by some rich person in Silicon Valley. If there were sources of steady funding, I am sure a lot of young astronomers would take a job searching for intelligent life.


The Evening Star-Venus.

Anybody who has looked up into the western sky after sunset in the past month will have noticed a brilliant white object – the planet Venus, sometimes called the Evening Star. It is brighter than any other planet and ten times brighter than the brightest star Sirius.

The “Evening Star” Venus next to the Moon just after sunset – image from NASA

There are three reasons why Venus is so bright. Firstly, it comes closer to the Earth than any other planet. Secondly, it is relatively large compared to other inner planets, roughly twice the diameter of Mars and three times that of Mercury. Although the giant planets – Jupiter, Saturn Uranus and Neptune – are larger than Venus, they are further away and so appear smaller. Thirdly, the thick clouds which completely cover Venus reflect most of the light back into space. In fact Venus reflects 77% of the sunlight hitting it, more than any other planet. Venus is so bright that it even possible to see it during daylight. If you know exactly where to look it appears as a faint white dot against the bright blue sky

Venus over the next two years

Venus is both closer to Sun and moves faster in its orbit than the Earth and, on average, it takes 584 days for Venus to be in the same place in its orbit as seen from the Earth. The reason for this 584 day cycle is given in the notes at the bottom of this post. Because the orbit of Venus is inside the Earth’s orbit, Venus can never appear too far away from the Sun in the sky. In general it is only clearly visible for at most a few hours before sunrise or a few hours after sunset (see note 2). The two points where Venus appears furthest away from the Sun are called the greatest elongation points and are marked as A and B in the diagram below.

Data from Espinak (2014)

Venus has just passed a greatest elongation point which it reached on 12 January 2017, and it is a brilliant object in the western sky, visible for at least 3 hours after sunset, depending on your latitude. Over the next few month as it gets closer to the Sun it will be visible for a shorter and shorter time after sunset. On 25 March Venus will pass between the Earth and the Sun. This is known as inferior conjunction, and for a few weeks or so either side of this date Venus will be very difficult to see because it will only be visible in daytime close to the Sun.

Looking the diagram above, you might think that Venus will pass directly in front of the Sun at inferior conjunction. However, this diagram only shows the picture in two dimensions. As shown below, because the orbit of Venus is tilted with respect to the Earth, at inferior conjunction it normally passes above or below the Sun.

Rarely at inferior conjunction Venus will pass directly in front of the Sun. When this occurs it is known as a transit of Venus.

A transit of Venus. Venus is the dark dot crossing the Sun’s surface – image from Wikimedia Commons

After inferior conjunction, it will appear to move away from the Sun and will rise and set earlier in the day and will start to become visible in the eastern sky before sunrise. At this point in its orbit Venus is known as the Morning Star. It will reach the other greatest elongation point on 3 June 2017, when it will be visible for least 3 hours before sunrise.

After reaching the greatest elongation, Venus will start to move closer to the Sun again. It will be visible for a shorter and shorter time before sunrise. On 9 January 2018 Venus will be directly behind the Sun. This is called superior conjunction and, for a few weeks or so either side of this date, Venus will be very difficult to see because it will only be visible in daytime and will appear close to the Sun. After superior conjunction Venus will appear in the evening sky after sunset and as it gets further from the Sun it will be visible for longer and longer before the Sun sets

On 17 August 2018 Venus will reach the greatest elongation point it had previously reached on 12 January 2017 and once again it will be visible for at least 3 hours after sunset as a brilliant object in the western sky.

Venus’s phases during the 584 day cycle

As seen from the Earth over the 584 day cycle, Venus goes through a full set of phases in a similar way to the Moon. However, because Venus appears so small, these are only visible through a telescope.

At inferior conjunction, point A in the diagram above, when Venus is between the Earth and the Sun, the sunlit part of Venus faces away from us making the planet almost invisible. The amount of the sunlit part of Venus we can see gets larger or waxes through to a crescent phase (B), to a half Venus (C) at the greatest elongation and then to a full Venus at superior conjunction (D), when the whole sunlit side facing the Earth is illuminated. It then gets smaller or wanes back to a half Venus (E) at greatest elongation, then to a crescent (F) and then finally back to being almost invisible at inferior conjunction

Galileo’s discovery

The first person to discover the phases of Venus was the Italian astronomer Galileo Galilei (1564-1642).

Image from Wikimedia Commons

In 1543, just before his death, Nicolas Copernicus (1473-1543) had published the theory of heliocentrism which was completely revolutionary in its day – that the planets orbit the Sun. However, in Gallileo’s time, the teaching of the Catholic church favoured geocentrism, the widely held view that the Earth was the centre of the Universe and the stars, planets, the Sun and the Moon were in orbit around it. Indeed certain verses of the bible could be interpreted as supporting that viewpoint, such as Psalm 104:5 “the Lord set the earth on its foundations it can never be moved.”

However, the phases of Venus and the way that it appears smaller when it is a full Venus can only be fully explained by Venus orbiting the Sun, not the Earth. Therefore, Galileo concluded that the geocentric theory was incorrect. Unfortunately for Galileo, in 1616 the Catholic church declared heliocentrism to be heresy. Heliocentric books were banned and Galileo was ordered to refrain from holding, teaching or defending heliocentric ideas.

Despite this ruling Galileo continued to defend heliocentrism, and in 1633 the Roman Inquisition found him “vehemently suspect of heresy”, sentencing him to indefinite imprisonment. Galileo was kept under house arrest until his death in 1642.

However the facts cannot be disputed. When viewed through a telescope Venus does show changes in size and shape, which can only be satisfactorily explained in a heliocentric model. Eventually, in 1758, the Catholic Church dropped the general prohibition of books advocating heliocentrism.

And finally….

I hope you have you have enjoyed this post. In 2015 and 2016 I published a series of posts on Venus. Some of them are listed below.

Venus a Mysterious world describes Venus in science fiction and compares it these depictions of the planet to reality.

Akatsuki – a second chance describes the mission of the Japanese spacecraft Akatsuki which is currently in orbit around Venus studying its weather. The spacecraft should have gone into orbit in 2010. This didn’t happen but mission control were able to successfully put the spacecraft in hibernation for 5 years before making another successful attempt.

Terraforming Venus describes how in the future we could alter Venus to make it more Earth-like so that we could live on the planet without needing any special protective equipment.

(1) The diagrams below illustrate why it takes 584 days for Venus to be in the same position in its orbit in relation to the Earth. Venus and the Earth in their orbits around the Sun are like two runners on a track. The Earth takes 365.256 to do one circuit, whereas Venus, whose orbit is inside the Earth and moves faster around the Sun, only takes 224.701 days to do one circuit.

The point in time when Venus is closest to the Earth and lies between the Earth and the Sun is called inferior conjunction. The time interval between one inferior conjunction and the next is the time it takes for Venus to ‘gain a lap’ in its orbit around the Sun. This is shown in the diagrams below.

After approximately 580 days Venus and the Earth line up again.

In fact, because the Earth’s and Venus’s speed in their individual orbits aren’t constant but varies slightly, the interval between one inferior conjunction and the next also varies between 580 and 588 days.

(2) Strictly speaking, this depends on the latitude of the observer. Venus is visible for much longer at higher latitudes.

There is now a video on the Explaining Science YouTube Channel which describes Venus’s orbit and phases. To view it, please click on the link below


Why did Venus lose its oceans?

I watched an episode of the new Cosmos series and in it the astronomer mentioned that Venus receives 30% more solar radiation than the Earth but that was not the cause of the out of control global warming on Venus. Further he said that Venus had oceans similar to Earth but lost them early.

I wondered why Venus lost its' oceans? If the atmosphere of early Venus was as thick as that on Earth then surely this would provide some protection for light elements such as hydrogen from being stripped from Venus. I know that Venus does not have a magnetic field generated internally (although it has a magentotail). Is that the reason Venus lost its' oceans?

Further, I know that Venus does not have plate tectonics currently. I know that water is believed to be a lubricant allowing plate tectonics to exist. But is there any data to indicate whether Venus had plate tectonics formerly when it had oceans - or was the lack of plate tectonics responsible partially for the warming and volcanic activity seen on Venus currently - perhaps helping to boil away the oceans of Venus?


Watch the video: Το Σκοτεινό Πρόσωπο της Θεάς Αφροδίτης! Ελληνική Μυθολογία (January 2023).