So, I received an email from my mother a few days ago, with the subject "Mars". It seems she received it from a cousin, who from a co-worker, and so on and so forth. A chain message. Well, with the title "Mars", how could I not check it out. It simply contained a Powerpoint presentation and many replies of "Is this true?" and "Neat if true!" from many of the people responding. Here is the presentation, in its multicolored glory:
Check it out, guess no one will get much sleep in August.
Mars The Red Planet is about to be spectacular!
-This month and next, Earth is catching up with Mars in an encounter that will culminate in the closest approach between the two planets in recorded history.
-The next time Mars may come this close is in 2287.
-Due to the way Jupiter's gravity tugs on Mars and perturbs its orbit, astronomers can only be certain that Mars has not come this close to Earth in the Last 5,000 years, but it may be as long as 60,000 years before it happens again.
-The encounter will culminate on August 27th whenMars comes to within 34,649,589 miles of Earth and will be (next to the moon) the brightest object in the night sky. It will attain a magnitude of -2.9 and will appear 25.11 arc seconds wide.
-At a modest 75-power magnification
Mars will look as large as the full moon to the naked eye.
Mars will be easy to spot. At the
beginning of August it will rise in the east at 10p.m.
and reach its azimuth at about 3 a.m.
By the end of August when the two planets are
closest, Mars will rise at nightfall and reach its
highest point in the sky at 12:30a.m. That's pretty
convenient to see something that no human being has
seen in recorded history. So, mark your calendar at
the beginning of August to see Mars grow
progressively brighter and brighter throughout the
month.
Share this with your Children and Grandchildren!
No one alive today will ever see this again
Wow! So Mars will be so close to the Earth that it will be as big as the moon in the sky?! Amazing! Well, it would be quite a sight...if only it were true.
Alas, this is a very popular myth that has been around since 2001, and resurfaces around this time every year. It's hard to blame people for getting sucked in by this. I would say a large majority of people in this country do not understand actual gravitation physics, much less orbital mechanics. Without these, the idea of seeing Mars the size of the Moon might not seem like a big stretch of the imagination. I mean, who's to say that just for a short time, Mars can come close enough to provide such a sight? I plan to be the naysayer here.
Mars, like the Earth, is in an orbit around the sun. Although it is usually thought that planets orbit in circular orbits, this is not exactly true. They actually orbit in elliptical paths around the sun, a bit egg shaped, but much more subtle. Because of such orbits, there are times when the planet is close to the sun and times when it is then farther away. As seen in the picture of the inner planets, the left side of the orbits are closer to the sun (and each other) than the right side. This is one reason for seasons, along with the tilt of the Earth.What does this have to do with Mars being the size of the Moon? It's all about distances. When Mars is a the smallest part of its orbit (far left on the picture) and the Earth is at the most distant (far right), the two planets are close to 400 Million miles away; but when they are both at the smallest parts of their orbits and lined up, they can be as close as 59 million miles away. Much closer, but still quite the distance. This is also the closest the two planets can get. Period. And what does Mars look like to the naked eye at it's closest distance? A small, red-ish dot.
Here you can see the Moon, Venus, and Mars.
Mars is the smallest dot in the top right.
So, what would it take to get Mars the size of our Moon in the night sky? Well, Mars is roughly twice the size of the Moon, so it would need to be roughly twice as far away from Earth as the Moon. Our Moon is 240,000 miles away, so that would mean Mars would need to be 476,000 miles away...MUCH closer than its closest 59 Million miles mark. This would obviously mean either Mars, or the Earth and the Moon are out of their orbits around the sun. That simple fact alone would spell doom for the runaway planet, especially Earth, but assuming it is only Mars out of orbit, the gravitational effects alone between the two planets would cause chaos on Earth. Things that I believe a new Steven Spielberg movie will be looking into. Boom. Product placement.
So, in the end, we'll just have to leave it to the movie to see a planet the size of our Moon in the night sky. Hope I enlightened someone with this.
