I can remember being fascinated with space ever since I was a very young child. The first thing I did when we got our elementary school science text books was flip to the part about the planets so I could make sure that I had something to look forward to during class. This is no secret to the people I know and I am often the one that gets a text message or an email when someone has a question or hears about something really cool –or really outrageous and hopefully not true- that is supposed to happen.
I would say I am surprised at how easily false assumptions or misinterpreted information can be spread as “truth” but it is so easy to innocently pass on something interesting and simply assume that the person who gave you the information wouldn’t pass it along if it weren’t true – even if you don’t even know the person because you found it online. It’s so easy to assume responsibility onto another person to avoid the trouble of having to look up information before one passes something false to another person. Personally, I am a research junky and I really enjoy looking up information and learning new things even if they seem small or irrelevant. In the following examples it’s definitely obvious that reality is actually more interesting than any myth.
The Myth: Mars will be as big as the full Moon during opposition.
It has been said that if you gaze at the night sky during Mars’ opposition you can spot the lovely red planet posing as large as the full Moon herself. It is apparently a once-in-a-lifetime event that you don’t want to miss. This comes up every single year and, without much surprise and without even a second thought, never holds to the truth. No one has nor ever will see Mars as large as the full Moon in the night sky from our lands (or sea) here on Earth.
This image was taken within minutes of Mars’ closest approach to Earth in 60,000 years, on Aug. 27, 2003. In this picture, the red planet is 34,647,420 miles (55,757,930 km) from Earth.
Credit: NASA, J. Bell (Cornell U.) and M. Wolff (SSI)
Reality: This rumor was started by a chain email that began circulating in 2003 when Earth and Mars were at a record-breaking close distance of only about 56 million kilometers apart. Even then Mars was still 75 times smaller to the naked eye than the full Moon and that’s pretty close considering that when the planets are at their farthest they are about 401 million kilometers apart. That’s more than seven times as far!
When Mars is in opposition it is in the opposite side of the sky as the Sun as viewed from Earth. This means that the Sun, the Earth and Mars form a straight line with Earth sandwiched in the middle. When planets are in opposition to the Earth they are at their closest to one another.
Two famous rumors (among many others) are that Mars’ opposition is an extremely rare occurrence that won’t happen again in this lifetime and it will look as large as the full moon in the sky. The only way to truly see the red planet that large would be to travel to her dusty plains one’s self and she glides into opposition with the Earth about every two years.
Shortly before the 2003 astronomical event the public began receiving and forwarding a pesky chain email that haphazardly stated that “Mars will look as large as the full Moon if you magnify it 75x using a backyard telescope.” and more often than not the second half of the sentence was even separated from the first part and people never paid it any attention. It seems that people are too quick to forget that they live in an age of information and finding the truth to any bogus claim is as simple as typing a question into a search bar. That aside, while Mars was actually 75 times smaller than the full Moon in the sky it still doesn’t quite equate to the hypothesis that viewing it magnified that many times would look even close to how the full Moon looks to the naked eye in the sky.
“A good reference is the Moon Illusion. Moons on the horizon look huge; Moons directly overhead look smaller. In both cases, it is the same Moon, but the human mind perceives the size of the Moon differently depending on its surroundings.” says Dr. Tony Phillips in Return of the Mars Hoax.
The same concept applies to Mars, and when one is viewing it through the long, dark barrel of a telescope it is going to look much tinier than the full Moon regardless of magnification strength.
The Myth: Meteors are falling stars.
Anyone who has ever seen a meteor knows that it was probably just a star falling from its perch up there in the sky. I mean, they are about the same size as stars – sometimes much bigger- so they have to be stars, right? Not so much.
A Storm of Meteors in 1999 Credit: NASA This image was taken during the 1999 Leonid meteor storm as part of NASA’s Leonid Multi-Instrument Aircraft Campaign (Leonid MAC). The image was captured with a 28 mm camera.
Reality: Meteors are caused when tiny particles left over by comets and asteroids combust upon entering our atmosphere. Comets are continually losing matter that forms river of particles that follow its eccentric orbit around the sun. The Earth is also orbiting the Sun and its orbit passes through that of the comet and these left over particles slam into our atmosphere and dazzle the world. Most of the time these particles burn up completely before ever reaching the ground but on the very rare occasion that the meteor was big enough to survive the plummet we call them meteorites and they are incredibly valuable to science because we can study the composition of the comet or asteroid that is known to produce that particular shower.
The Myth: The Great Wall of China is the only man-made object visible from the Moon.
Long before man even stepped foot on the Moon it has been boasted that The Great Wall of China would be visible from its surface with just the naked eye. But it was all really just speculative hype until we were able to take a look from the surface of the moon ourselves.
This photo of central Inner Mongolia, about 200 miles north of Beijing, was taken on Nov. 24, 2004, from the International Space Station. The yellow arrow points to an estimated location of 42.5N 117.4E where the wall is visible. The red arrows point to other visible sections of the wall. Credit: NASA.
Reality: It turns out that from about 237,000 miles away,
“The only thing you can see from the Moon is a beautiful sphere, mostly white (clouds), some blue (ocean), patches of yellow (deserts), and every once in a while some green vegetation. No man-made object is visible on this scale. In fact, when first leaving Earth’s orbit and only a few thousand miles away, no man-made object is visible at that point either.” says Apollo 12 Astronaut Alan Bean.
Taken by Apollo 8 crew member Bill Anders on December 24, 1968, showing the Earth seemingly rising above the lunar surface. Note that this phenomenon is only visible from someone in orbit around the Moon. Because of the Moon’s synchronous rotation about the Earth (i.e., the same side of the Moon is always facing the Earth), no Earthrise can be observed by a stationary observer on the surface of the Moon.
The myth has since generalized into saying that the wall is visible “from space” and usually doesn’t specify whether it means visible with the naked eye nor does it specify how far out in space we are looking from. Even assuming that it means through the naked eye and from low-Earth orbit, the wall is made of material that is a similar color and texture to the surrounding land and it is barely discernible if not downright invisible. Oh, and other man-made objects are definitely visible from space.
If you’re also interested in making sure the facts about any myth are readily available for you to reference in a debate, you can start by helping the skeptic community take measure to ensure scientific quality and skepticism on Wikipedia. Check out Susan Gerbic’s blog Guerrilla Skepticism on Wikipedia.
Sources:
Opposition (Planets) – Wikipedia
Approaching Mars – Science@NASA
Beware the Mars Hoax – Science@NASA
Return of the Mars Hoax – Science@NASA
The Mutating Mars Hoax – Science@NASA
Mars Will Look as Big as the Full Moon – Astronomy.com
China’s Wall Less Great View From Space – NASA
Is China’s Great Wall Visible from Space? – Scientific American
Man-Made Structures Visible From Space – Wikipedia
Picture Album: Hubble’s Closest View of Mars — August 27, 2003 – Hubblesite
Most Amazing Leonid Meteor Shower Photos – Space.com
Do Stars Move? – Universe Today
How Meteor Showers Work (Infographic)
Further Reading:
Astronomy: Why is a Harvest Moon So Large? - astro.wsu.edu
Meteor Showers and Shooting Stars: Formation, Facts and Discovery -Space.com
It doesn’t take much thought to cast doubt on the meme about the Great Wall of China being visible from space. Although it’s extremely long, the vast majority of it isn’t any wider than the average house, and if you could see something of that size from space there would be an equally long list of man-made objects that could be spotted from a low orbit.
Exactly, and the wall blends in with the surrounding land because it is made out of brick and earth, among other things. Even in low Earth orbit It’s like trying to find a lizard in a terrarium from 10 feet away.
Thank you Dani for the shout out about our project Guerrilla Skepticism on Wikipedia! You are 100% right. Wikipedia is where most people get their information and we need to make sure it is excellent information.
You’re welcome!
Would love for you to do a post about how the moon appears larger in the sky sometimes and common myths about why that is. Not really my expertise but sound like up your alley.
Great idea! Thanks, Stephen.
2 other myths about space that I often come across are regarding its size!
First, most people know that the age is generally accepted to be about 14 billion years and thus many believe that the size is either 14 billion light years, or 28 billion light years across – as it is natural to assume that light has moved in every direction since the big bang. And, as we all know, nothing can move faster than just below 300 million metres per second; the size of the universe must therefore be limited by the speed of light.
This logic works, but it is wrong:
Even though nothing can move faster than the speed of light, this does not apply to the expansion of spacetime. Spacetime is sort of the sea in which all the solar systems are floating. When we take this expansion into consideration the best estimations we have of the size is actually somewhere around 96 billion light years.
A popular analogy is often to imagine running at a constant speed on a strip of asphalt road which is being stretched underneath you. Your speed does not change, but the distance between you and the start is calculated by adding your speed to this stretch and thus the distance you have finally moved is actually greater than your speed.
Anyways, difficult to accept although this is how the size is conceived and factually backed by both observations and mathematics.
The second myth is then born from the one above. Because the 96 billion light years is not actually the estimate for the entire universe, but “only” for the observable part of the universe. There is no sane estimation for the entire universe, which might very well be much much much greater, but there is no way we can really tell. In other words when size is being discussed it is generally implied to be concerning the observable part.
Very interesting, thanks!
You’re welcome!
Check out my post on the Moon Illusion:
http://skeptoid.com/blog/2013/02/01/the-moon-illusion/