There are a whole lot of persistent space rumours lurking around the Internet, like the one where an asteroid is about to wipe out life on Earth, or that on January 4, planetary alignment will drastically decrease Earth's gravity. One that just won't seem to go away is the myth that on August 27, people will see two moons in the night sky because Mars will suddenly appear the same size as the Moon - also known as 'Mars Spectacular'.
"Mars will look as large as the Full Moon," according to the email chain that's been forwarded around (and now has made its way onto Facebook) for the past 12 years. "No one alive today will ever see this again."
We shouldn't really have to say this but, no, that's not going to happen. NASA and the Canadian Space Agency have both publicly debunked this rumour plenty of times, but seeing as it's still circulating, we thought we'd throw our hat into the ring and make it plainly clear to everyone reading that Mars will not now, nor will it ever, appear as big as the Moon. Shall we take a look at some of the facts?
For starters, Mars is really f*cking far away - around 225 million kilometres far, depending on when you measure it. The Moon is pretty far away too, at a distance of roughly 384,400 kilometres, but it's still much, much closer to Earth than Mars will ever be. That means that even if the two objects were exactly the same size (which they're not, Mars is bigger), the Moon will always look larger to us.
And even when magnified by a telescope, the Red Planet is never going to look anywhere near as big as the Moon, insist the experts. We should also add that if Mars really did suddenly appear as large as the Moon in the night sky, we'd be dealing with some crazy tidal activity here on Earth as a result.
So where did this myth come from? The email chain that started the hoax seems to have stemmed from a scientific misunderstanding back in 2003, when Mars made its closest approach to Earth in 60,000 years on, you guessed it, August 27.
That meant that Mars did indeed appear larger than usual - six times so, in fact. But it was still a very long way off being anywhere near the size of the Moon, and it was still 56 million kilometres away from Earth.
The original email did also provide some details on needing to use a telescope to see this effect, but even that wasn't true, and, naturally, those instructions were left off the email once it went viral. Hence the confusion.
So we're sorry. You're not going to see Mars swell up to the size of the Moon overnight this week. Or as the Canadian Space Agency declared on Facebook a few days ago: "No, no, no and no!"
But the good news is that Mars is awesome all the time, regardless of its position in the night sky. And we currently have a robot exploring it for us! So while it may not look as big as the Moon, we think it's always worth sharing with others how spectacular the Red Planet really is.
H/T: io9