Astro-Hoaxes to Laugh at (But Not Take Seriously)

Planetoid crashing into primordial Earth

Donald Davis / Wikimedia Commons / Public Domain 

Every year we see stories about how Earth is going to be hit by an asteroid, or that Mars will be as big as the full Moon, or a NASA probe has found evidence of life on Mars. In fact, the list of astronomy hoaxes is never-ending.

One way to find out what's really happening is to check out the debunking site Snopes. Their writers are usually on top of the latest stories, and not just in "weird" science.

Earth as a Target: Maybe, but Not the Way You Think

The recurring story about Earth and an incoming asteroid usually shows up in the supermarket press, often with a projected date, but few other details. It almost always cites NASA, but doesn't name a scientist who is making the prediction. In addition, the story rarely mentions amateur astronomers and their observations. There are thousands of these people around the world watching the skies, and if an incoming asteroid were to be on a collision course with Earth, they'd see it (unless it was really quite small).

It is true that NASA and a world-wide group of both professional and amateur observers are monitoring the space near Earth for any possible Earth-crossing asteroids. Those would be the most likely types of objects to pose a threat to our planet. Announcements of Earth-crossing or Earth-approaching asteroids would show up at the NASA Jet Propulsion Laboratory Near Earth Object Program web page. And such objects are usually spotted pretty far in advance.

The known "Potentially Hazardous" asteroids have very, very small chances of colliding with Earth in the next 100 years; it's less than one tenth of one percent of a chance. So, the answer to whether or not there's an asteroid homing in on Earth is "No."

Just no.

And, for the record, supermarket tabloids are not scientific journals.

Mars Will Be as Big as the Full Moon! 

Of all the astronomy hoaxes to circulate on the web, the idea that Mars will look as big as the full Moon on some given date is one of the most inaccurate. The Moon lies 238,000 miles away from us; Mars never gets closer than 36 million miles. There's no way they can look the same size, not unless Mars wants to get a lot closer to us, and if it did, it would be pretty catastrophic.

The hoax began with a poorly worded email announcing that Mars — as seen through a 75-power telescope — would look as big as the full Moon would look to the naked eye. This was supposed to occur in 2003, when Mars and Earth were closest to each other in their orbits (but still more than 34 million miles apart). Now, the same rumor comes around every year.

No matter where we are in our orbits with respect to each other, Mars will look like a small point of light from Earth and the Moon will look big and lovely.

NASA Is (Not) Hiding Life on Mars

The red planet Mars currently has two working rovers on its surface: Opportunity and Curiosity. They are sending back images of rocks, mountains, valleys, and craters. Those images are taken during daylight hours under all kinds of lighting conditions.

Occasionally an image shows a rock in the shadows. Due to our propensity to see "faces" in rocks and clouds (a phenomenon called "pareidolia"), it's sometimes easy to see a shadowy rock as a form, a crab, or a statue of a debutante. The infamous "Face on Mars" turned out to be a rocky bluff with shadows that looked like eyes and a mouth. It was a trick of light and shadow playing across rock outcrops and cliffs.

It's like the "Old Man of the Mountain" in New Hampshire in the United States. It was a rock overhang that, from one angle, looked like an old man's profile. If you looked at it from another direction, it was just a rocky cliff. Now, because it cracked and crashed to the ground, it's a pile of rock.

There are already some pretty interesting things on Mars that science can tell us about, so there's no need to imagine fantastic creatures where only rocks exist. And, just because Mars scientists debunk the existence of a face or a rock that looks like a crab does not mean they're hiding life on Mars. If they had found any shred of evidence of living beings on the red planet now (or in the past), it would be huge news. At least, that's what common sense tells us. And common sense is an important factor in doing science as well as exploring the universe.