See the Red Planet with Your Own Eyes
Mars reaches opposition this weekend, making Saturday and Sunday (May 21 and 22) an opportune time to see the Red Planet with your own eyes.
This Sunday morning (May 22), Mars reaches opposition with the sun. This means that the Red Planet will be exactly opposite the sun in Earth's sky, making this weekend a great time to see it for yourself. In fact, Mars will soon be at its closest point to Earth in over a decade.
Because Mars is directly opposite the sun (in relation to Earth) during opposition, Mars rises as the sun sets, and sets as the sun rises. This also means that Mars is visible all night long this weekend. To mark the occasion, NASA scientists used the Hubble Space Telescope to capture an absolutely stunning view of Mars as it nears opposition.
The exact time when Mars will be above the horizon depends on your location. For example, in New York, Mars rises in the East at 8:10 p.m. EDT and sets in the West at 5:35 a.m. EDT, so it is above the horizon for 9 hours and 25 minutes. Farther south, it will be visible longer, and farther north, for a shorter time. [Video: Mars: Hubble Telescope's Eye on the Red Planet]
The easiest way to spot Mars this weekend is to go out when the Red Planet is highest in the sky, close to midnight local time. Remember that if you live in a part of the world that is on daylight saving time, that "sweet spot" of viewing times will be close to 1 a.m. your local time.
If you live anywhere north of the equator, Mars will be due south at midnight local time. If you live south of the equator, Mars will be high overhead. On opposition night, Mars will be close to the nearly full moon, and will be the brightest object in the sky, except for the moon and Jupiter, over near the western horizon. Look for Saturn and the bright-red star Antares nearby.
What Mars looks like
The most striking thing about Mars' appearance to the naked eye is its red color. This will be particularly clear if you compare it with Jupiter over in the west. They are almost equal in brightness, but Jupiter is a pale cream color, whereas Mars is noticeably red.
If you view Mars through a telescope, you are likely to be disappointed. All of the planets are much smaller than people expect, and this is particularly so with Mars, because it is one of the smallest planets in the solar system; only Mercury is smaller.
You may have heard an internet rumor that, on a particular date, Mars will appear as large as the moon. This is physically impossible, because Mars is always much farther away than the moon, and never appears larger than 1/70 ofthe diameter of the moon. On opposition night, Mars will be only 1/100 of the diameter of the moon. In other words, it will take a telescope magnifying 100 times to make Mars look as big as the moon as seen with the naked eye.
It takes a trained eye to see detail on a disk that small. Experienced planetary observers spend years sketching Mars at every opportunity, trying to catch the rare instants when Earth's atmosphere steadies enough to reveal Mars' secretive details. It takes patience and an optically excellent telescope.
Usually, Mars observers first look for the planet's polar ice caps. However, this year, Mars is close to its equinox, so both polar caps are at their smallest, and thus hard to see. What may be visible is the pale haze that forms over the polar regions.
It is usually possible to see so-called albedo markings, variations of dark and light caused by the alternation of bedrock and desert sands. The darker areas appear grey-green, while the lighter areas are a pale peach color. The contrast between light and dark is very low but may be enhanced by using a red or orange filter.
See Mars at its closest since 2005
Oddly enough, although Mars is directly opposite Earth on Sunday morning, it is not at its closest.
Because of Mars' eccentric orbit, it will still be getting closer to Earth on opposition night, and won't reach its minimum distance (and largest size) until almost a week later, on May 30 at 6 p.m. EDT (2200 GMT). The difference is only 5 percent, which is too little to make much difference.
On May 30, Mars will be the closest it has been to Earth since November 2005, giving us the best view we have had in over a decade. Don't miss it.
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On Sunday morning (May 22) at 7 a.m. EDT, Mars reaches opposition with the sun.
Mars has two small moons, Phobos and Deimos, that orbit above the Red Planet's surface. Phobos has been in the news lately because the moon is doomed, and scientists have some new findings about its possible fate. What else do we know about Phobos? Read on to find out.
Phobos sports an impact crater that is large relative to its size. Called Stickney, it's about 9.5 kilometers (5.9 miles) across and likely came from an impactor that was so big, Phobos almost broke apart. Secondary craters created by the impact mess up a commonly used technique called "crater counting" to estimate how old the surface of a moon or planet is, according to the
. An area with fewer craters could be more eroded -- and older -- than an area with more craters. But this does not work on Phobos.
So we all know that Phobos is doomed, but precisely what is happening to it is still a subject of debate. These grooves you see in the picture were once believed to be the result of whatever hit Phobos and created Stickney crater. New research, however, suggests these are
. Phobos is supposed to hit Mars in 30 million to 60 million years, but these marks would show the moon will never make it. Instead, it would rip apart and create a small moon around Mars.
Phobos is a really dusty place. Observations from Mars Global Surveyor suggest that there is dust about one meter thick on the small moon, suggesting a lot of erosion from impact craters over the years. You can see evidence of some of these craters in the picture above.
Phobos orbits quite close (6,000 km or 3,700 miles) to Mars, appearing half as big as Earth's moon in the sky despite its diminutive size. It whips around the planet every 7 hours and 39 minutes, which means that unlike Earth, it rises in the west and sets in the east. The moon is in fact so close to Mars that it isn't visible from all points on the planet; the curvature of Mars gets in the way.
It's not very clear if Phobos was captured by Mars long ago, although the European Space Agency
hint it could have been an asteroid. But other evidence suggests it could have formed at Mars because its orbit is circular, or that (because its composition appears so primitive) perhaps it could have been the leftovers of a past moon or "ejecta" from Mars' surface.
Image: Asteroid 951 Gaspra (top) compared with the two moons of Mars: Deimos (lower left) and Phobos (lower right).
To get a body or feature on a body officially named in space, you need to go through the International Astronomical Union. The IAU has naming rules for each of the planets and moons in our solar system, among other locations. On Phobos, this is what it says is needed: "Deceased scientists involved with the discovery, dynamics, or properties of the Martian satellites, and people and places from Jonathan Swift's 'Gulliver's Travels'." The latter sounds a bit strange, but was decided because Swift mentioned two Martian moons in his fictional 1726 book. Phobos wasn't discovered until 1877.
Image: The first edition of "Gulliver's Travels", a 1726 book by Jonathan Swift.
Even though dozens of missions have gone to Mars, nothing has been able to get all that close to Phobos -- at least yet. Not to say people haven't been trying. In 1988, the Soviet Union attempted to send two probes called Phobos 1 and Phobos 2, both of which failed en route. Russia also attempted to send a mission called Phobos-Grunt in 2011, which got stuck in Earth orbit after its launch (pictured here). Luckily for science, several Mars missions have been able to capture imagery of the satellite -- imagery you have seen in this slideshow.