The short answer is “no – you won’t see a double moon this year, or any year.”
Unfortunately this is a hoax that’s been circulating for the last 12 years or so, and asks the question “will the Moon and Mars ever appear to be the same size?”
The viral headlines are doing the rounds again enticing you in by using words like “spectacular” and “a once in a lifetime experience.”
The sad thing is many people are still taken in by this hoax – and end up being disappointed when they miss the once in a lifetime experience – that will never happen, and I personally would hate for people to be put off looking up into the night sky, because they are let down by a viral hoax.
Is it ever possible for Mars to appear as big as the Moon?
The only way for this to happen would be for Mars to break its orbit, and travel towards the Earth to pretty much the same distance from the Earth as the Moon.
Mars at the moment (August 2015) is on the far side of the Sun from us – and therefore 250 million miles (around 401 million km) away from us. The closest Mars ever gets to the Earth is around 34 million miles (56 million km).
The Moon on the other hand, is only 238,000 miles (383,000 km) from Earth. On average, Mars is around 200 times farther away from the Earth as the Moon is.
To put that into perspective, light reflected from our Moon takes around 1 second to reach us. Light reflected from Mars can take a few minutes (when it’s closest to us), and up to around 20 minutes (when it’s furthest away – on the far side of the Sun)
Mars has a diameter of 6,787km, and the Moon’s diameter is 3,476km – just under twice the size of the Moon. For it to appear as big as the Moon in our night sky, Mars would have to be around 75 times larger than it actually is.
How did the hoax start?
Back in 2003, Mars and the Earth came closer together than they had been for thousands of years. This meant that Mars did indeed appear larger in the night sky than it ever had done, but not even close to the size of the Moon. That fact seemed to grow arms and legs, and ended up being the “double moon” story we see doing the rounds.
Will you see a double moon this year? No, unfortunately it’s a hoax, sorry! But please don’t let that put you off looking up into the night sky. There are so many truly fascinating sights to see – and hopefully my site is helping you discover some of them.