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Mars has been in the news lately.
Earlier this month, scientists announced the discovery of organic compounds on the red planet, which is not evidence of a past primitive life. But that's yet another indication that microbial life may have existed on Mars in the distant past. Other than the place where we live, Mars is the most terrestrial planet of the solar system. It has polar ice caps, lots of frozen water and a day that only lasts a few minutes longer than a 24-hour Earth day.
Mars will be in the news again this summer because the third planet of the sun will come closer to us at any time since 2003.
It's something exciting if you have a decent telescope. Mars is half of the Earth, and he spends most of his time too far away from us to have the slightest chance to see the details of the surface in a small telescope. But on July 31st, Mars will be less than 36 million miles away, and for weeks on either side of this date, users of good telescopes will be able to see the southern polar cap of the planet and dark markings on the reddish Martian deserts. .
But 36 million miles is still a long way.
On July 31, March will appear slightly smaller than a football placed a mile away.
A favorable opposition
A few days before this approach is near, Mars is in opposition, or directly opposite, the sun of the Earth. Oppositions to Mars occur every two years, but very close oppositions occur every 15 or 17 years. The March 2003 opposition was the champion when the planet rose to 34,646,418 miles away. It was the closest Mars opposition for nearly 60,000 years.
The July 31 event has moved 1.2 million miles from March compared to 2003, so the upcoming event is very important. The proximity of Mars around the near approach means that Mars shines very bright in our night sky – appearing as a bright reddish embers rising in the southeast sky at the end of the July evenings.
Tiny in the eyepiece
But just because Mars is near, that does not mean that it is going to gain momentum in our telescope eyepiece. Mars will always appear as a reddish point with some surface features becoming evident in medium to large telescopes. The most notable will be the southern polar cap of Mars. Magnifications of 200 to 600 times in the telescopes will give the most satisfactory views. If you own a small department store telescope worth $ 200 or less, you'll probably have no luck with regard to the features of the Mars surface.
The disadvantage of the 2018 opposition
Before we get too excited about the Martian views from our backyards, there are a few things that could make these telescopic views of the Martian surface characteristics difficult or impossible to see even with the best telescopes.
Mars appears very low in the southern sky during the next opposition for observers at our latitudes. Observing any planet with a telescope when it is low in the sky means we are looking across many miles of our turbulent atmosphere, blurring what we see. It's much better when our target planet is high and we are looking through a smaller thickness of air.
When Mars is closest on July 31, it will appear 29 degrees above our southern horizon. It's about the same height above the horizon as three of your fist widths held at arm's length. That means we are going to look through our turbulent atmosphere, even if the planet is very close.
Observers in South America will enjoy Mars very high in the sky with much less air between them and the red planet. The best views and terrestrial images of Mars during this opposition could come from the south of the equator. In two years, however, Mars will appear high in the sky for us at a much more distant opposition in October 2020.
Another condition that could prevent good telescopic observations during the July opposition could be the Martian dust storms.
In recent weeks, even small-scale backyard astronomers have noticed large clouds of reddish dust sweeping large portions of Mars, obscuring all the details underneath. In 2001, a global scale dust storm obscured all elements of Mars with the exception of the polar ice cap.
The Martian atmosphere is 1 percent of the Earth's density, but the Red Planet still experiences tearful winds that can inflate huge amounts of its red dust and spread it over thousands of kilometers.
The website spaceweather.com regularly publishes amateur images of Mars.
If you have a question about astronomy, send it to Backyard Universe, PO Box 297, Stedman, NC 28391 or email [email protected].
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