Opposition to Mars

Today (December 18) at 23:45 UT (6:45 pm. Eastern US time), Mars will make its closest approach to the Earth for the year.

As the two planets circle the Sun, they are sometimes close to each other, sometimes far (picture two cars speeding around a racetrack, with the inner car (Earth) overtaking the outer one). Right now, as Earth passes inside of Mars, the two planets are about 88 million km (55 million miles) apart. This is called opposition, because Mars is directly opposite the Sun in the sky when this happens. Update: Oops! Opposition actually happens on the 24th; the shape of Mars’ and Earth’s orbits sometimes means opposition doesn’t happen at closest approach. Thanks to Tom in the comments below for pointing this out to me. And while it’s the closest Earth and Mars will be for a while, this is not a particularly close approach. The orbit of Mars is pretty elliptical, and right now we happen to be passing it when it’s farther from the Sun than usual.

The image above was taken by Hubble yesterday, on December 17 (and let me congratulate the Hubble Heritage Team on the speed with which they released this image– that’s amazing!). They’re releasing it in honor of the opposition event.

Now, let me be clear. Mars is small, and far away. Even through a decent telescope it’s not much more than an butterscotch-colored disk, with only a few features detectable (usually a bright icecap, or the faint smudge of a large area like Syrtis Major, the triangular region on the right of Mars in the picture). I’m not saying you shouldn’t take a look if you get the chance! It’s worth it just to see an alien world with your own eyes. Just be prepared to not see what Hubble sees.

And remember: Mars will not look as big as the Moon! But it is still a burning red beacon in the east shortly after sunset. If you go out around 9:00 p.m. or so you’ll see it rising in the east, with Orion and the Pleaides looming nearby too (on the right if you’re in the northern hemisphere, or if you’re standing on your head south of the Equator). It’s a pretty scene, so even if you don’t have access to a telescope, go outside and have a gander.

December 18th, 2007 10:36 AM by Phil Plait in Astronomy, Cool stuff, NASA, Pretty pictures, Science | 37 comments | RSS feed | Trackback >

37 Responses to “Opposition to Mars”

  1. Doc Says:

    I think you mean “shortly after sunset”.

  2. The Bad Astronomer Says:

    Oops! What an odd typo. Thanks, fixed.

  3. wÒÓ† Says:

    I was opposed to Mars before it was cool to be opposed to Mars.

  4. Joshua Says:

    NASA’s “What’s Up for December?” podcast claimed that Mars will be the brightest object in the sky this month, which seems just plain wrong to me. Isn’t Venus brighter, at the very least?

    I’m assuming they meant it would be the brightest object in that part of the sky, but that’s not what they said. Can you help clear this up?

  5. John Says:

    The God of War, burns brightly in our sky. Always worth a look.

  6. Evolving Squid Says:

    I’ve always enjoyed looking at Mars

    http://www.squidzone.ca/the_squid_zone/2005/10/the_red_planet_.html

    And as the family science geek, I get pestered with the “giant mars” thing every year. Makes me want to bust a telescope over people’s heads. In any case, I won’t be looking at Mars in the near future because it’s supposed to be overcast here for the next while…

    … and the snow in my yard is about a metre deep, which makes setting up a bit problematic.

  7. Michelle Says:

    I tried to look at it with my scope yesterday… Absolutely impossible. I’ve never seen such an unstable sight.

    Hopefully the air will settle down soon.

  8. Silly String Theory Says:

    I’ve been noticing how bright Mars is for a few weeks now- one advantage to winters here at 5000′ ASL is that the skies are super clear (well, when there are no clouds- a common thing, luckily) and it’s impossible to miss that bright red object off Orion’s right shoulder. A very pretty sight, even being scopeless as I am.

  9. JanieBelle Says:

    Joshua asked:

    NASA’s “What’s Up for December?” podcast claimed that Mars will be the brightest object in the sky this month, which seems just plain wrong to me. Isn’t Venus brighter, at the very least?

    Oddly, I’ve always thought the sun was brighter.

    I could be wrong.

  10. Michael Amato Says:

    I’ve been observing Mars for the past couple of months. I noticed the south polar ice cap melted away very fast as the martian summer started in Mars’ southern hemishere. Years ago the south polar cap seemed to have melted at a slower pace. I also noticed the north polar hood hangs on longer than it used to years ago. I really think this is a sign of global warming on Mars. I googled global warming on Mars and sure enough our many instruments on or above Mars indicate it is indeed warming up. Now we know Venus has already boiled over and Earth is warming up quickly. Now for the icing on the cake, Jupiter has formed a second long term storm called the Little red spot. This indicates to me that Jupiter must also be warming up because more storms indicate warmer temperatures. Come to think of it, Mars seems to have more dust storms than it used to when I was younger. I wonder if the sun is up to no good.

  11. Silly String Theory Says:

    JanieBelle, maybe that should be amended to read the NIGHT sky ;) Just trying to cover for NASA here- I guess that makes me an enemy of the Conspiriati.

  12. Tom Elmer Says:

    Opposition is actually on the 24th, but who’s being picky? :) ( http://seds.org/~spider/spider/Mars/marsopps.html )
    ( http://www2.jpl.nasa.gov/calendar/ )

    The more interesting part is that the moon will be full less than a day before Mars is at opposition. Due to the alignment, some people will be able to see the Moon occult Mars about 1/2 hour after full moon (1/2 day before martian opposition). (i.e. The Earth-Moon-Mars conjunction line will be about 1/2 degree from including the sun as well.)

    ( http://www.lunar-occultations.com/iota/planets/1224mars.htm )

  13. The Bad Astronomer Says:

    Ah, closest approach need not be on the day of opposition, of course! It depends on the shapes of the orbits. Nuts. Tom, you got me there!

  14. Carey Says:

    Silly stupid question - Why would the left/right orientation of Mars and Orion/Pleiades change as the observer moves to the Southern hemisphere?

    It seems to me (I’m imagining a very large human straddling enormous amounts of latitude) that, looking east, starting at Maryland latitude, as I move southward (to my right)…

    Oh, okay. I see.

  15. Michael Lonergan Says:

    I must state that I am opposed to anything Mars does.

    Actually, I had the pleasure of viewing Mars on it’s closest approach several years ago, through my 3.5 inch Mak/Cass scope. It was awesome to see it with my own eyes. I was able to see the polar icecap and some dark spots. We get spoiled with what we are seeing through the eyes of Hubble, but there is nothing like the experience of seeing these objects yourself, especially sharing it with my daughter, who was six at the time.

  16. Tom Elmer Says:

    I cheated… :) I had been looking up the occultation map to see if I’d be able to see it in Colorado when I visit relatives for the holidays and noticed that full moon, occultation, and martian opposition were all less than a day apart, so I was doing some back-of-the-envelope calculations when your post showed up in my Google Reader.

  17. Jack Hagerty Says:

    Evolving Squid says: “As the family science geek, I get pestered with the “giant mars” thing every year. Makes me want to bust a telescope over people’s heads.”

    Nothing works like the evidence of your own eyes. A few weeks ago when the moon passed Mars only a couple of degrees away, I dragged both my kids outside and said, “See? It’s not as big as the moon.” Of course they both knew about the “hoax”, but it’s still has a great impact to see them side-by-side.

    - Jack

  18. Jack Hagerty Says:

    Silly String Theory says: “it’s impossible to miss that bright red object off Orion’s right shoulder.”

    Don’t forget the bright red object that IS Orion’s right shoulder (Betelgeuse).

    - Jack

  19. Ken B Says:

    Silly String Theory:
    > one advantage to winters here at 5000? ASL is that the skies
    > are super clear

    Try it from 33,000 feet! Over the ocean! I was on an evening flight home last night, and had a great view from 33,000 feet above the Atlantic. Mars was quite bright, and I don’t remember ever seeing Orion quite as clear. I’m not sure if it was my imagination or not, but I’m pretty sure I was able to see M42 as well. (If only I had had my binoculars with me.)

  20. Ken B Says:

    Silly String Theory:
    > one advantage to winters here at 5000? ASL is that the skies
    > are super clear

    Try it from 33,000 feet! Over the ocean! I was on an evening flight home last night, and had a great view from 33,000 feet above the Atlantic. Mars was quite bright, and I don’t remember ever seeing Orion quite as clear. I’m not sure if it was my imagination or not, but I’m pretty sure I was able to see M42 as well. (If only I had had my binoculars with me.)

  21. Ken B Says:

    Sorry for the double-post, but I got errors both times I posted. (Apparently, the php/SQL errors occurred _after_ it successfully posted my comment.)

  22. Michael Lonergan Says:

    To Jack:

    What is really funny is that I had a dream last night where I was outside, and looked into the sky, and what did i see? Yes, the Moon, but right next to it? A Moon sized red Mars! :)

  23. bigjohn Says:

    Wadda ya mean Mars won’t be as big as the full Moon? Whut about all those emails I been gettin lately? I bin farwardin em to everybody too. I spect thar’ll be a ton of folks out looking at the sight. Leastwize down here in Texas we will. Soon as we has the Bible readin after supper.

  24. The Ill Tempered Klavier Says:

    Weel thar Big John Ah’d be right with ya on the Bible readin and throw in some right juicy bits outta the Book of Mormon too, ‘ceptin’ ah’d probly get mixed up an’ slip in sumptin’ outta the Book of Eibon or the Necronomicon an’ that’d cool the party quicker’n a CO2 fahr extinguisher.

    ‘Sides, Ah gotta tell ya, t’other night Ah set up mah ol’ 3″ f-10 newtonian what Ah got fuh $29.95 frum Edmund Scientific Co. {CENSORED} yeahs ago when Ah was about 12 and still got ‘cuz I kept ignorin’ mah Dad all them times he said, “Muffin, I won’t officially have an empty nest till you get your junk out of my garage.” An’ Mars only looks about like a BB through somethin’ like that theyah.

  25. Grumpy Says:

    The photo has no stars in the sky, therefore the image is fake! And faked poorly by some schmuck who doesn’t know there’s s’posed to be stars! It was probably Buzz Aldrin himself who faked it!

  26. The Bad Astronomer Says:

    Heh. I would actually bet that there are stars in the image! I’m sure the exposure times for the images that went into making this picture were short, but a 2.4 meter mirror in space can see even relatively dim stars in a fraction of a second exposure time. In this case, though, the background level was set high to make the picture pretty. :-)

  27. Lugosi Says:

    I recently had an appointment with my proctologist and he had a weird picture on his wall. I asked him, “What’s that?” And he said, “That’s a picture of Uranus.”
    Needless to say, I made him take it down.

  28. Michael Lonergan Says:

    I’d like to visit the Twin Moons of Uranus!

    About the Global warming thing on Mars, Jupiter, Saturn, Neptune, Pluto, and ah yes, Uranus: Didn’t the BA have a blog on this quite some time ago as this was making the “Conspiracy Theory” rounds? People were claiming the Sun was going wonky and it was refuted by the BA by explaining about the various temperature increases and what it would mean in relation to how distant each planet lies from the Sun?

    (I swear I have not touched a drink yet.)

  29. Michael Lonergan Says:

    Found it!
    Is global warming solar induced? April 29, 2007. This should answer the questions that Michael Amato has.

  30. Grand Lunar Says:

    I don’t think I’ve ever seen Mars as bright as it does. Mostly because at the other times, I didn’t know what to look for, or the Florida weather was clouding my vision!
    Unfortunately, my telescope isn’t with me now. I hope I get a chance to use it during my brief stay with my family at home.

  31. Michael Lonergan Says:

    Here’s a nice trick to play on the kiddies: Take them out Dec 24, point to that red dot in the sky, and proclaim, “Hey, look! It’s Rudolph!”

  32. Johnny Vector Says:

    a 2.4 meter mirror in space can see even relatively dim stars in a fraction of a second exposure time

    To be complete, it also helps when you have a really really good CCD, cooled to like -80 degrees C., and you take minutes to read it out. It’s amazing how low much lower the noise can be than in your $500 digital camera.

    I don’t actually know how long the readout takes on WFPC2, but it’s about 2 minutes to read out the 16 megapixels of ACS Wide Field Channel, and it’s likely similar. Though of course for ACS right now it’s 2 minutes plus the time between now and Servicing Mission 4.

  33. Barton Paul Levenson Says:

    Michael Amato posts:

    [[This indicates to me that Jupiter must also be warming up because more storms indicate warmer temperatures. Come to think of it, Mars seems to have more dust storms than it used to when I was younger. I wonder if the sun is up to no good.]]

    They found hot spots on Jupiter; they have not found global warming on Jupiter. The hot spots have probably been there (the phenomenon, I mean, not the individual columns) for billions of years. As for big dust storms on Mars, google “Mars Mariner dust 1971.”

    The sun can’t be responsible for current global warming on any planet since there has been no noticeable upper trend in sunlight for 50 years or more. We’ve been measuring Total Solar Irradiance from satellites like Nimbus-7 and the Solar Maximum Mission for many decades now, and have good proxies before that.

  34. Quiet_Desperation Says:

    Now, let me be clear. Mars is small, and far away. Even through a decent telescope it’s not much more than an butterscotch-colored disk, with only a few features detectable

    I showed Mars to a friend’s wife a few years back during a previous opposition. She sniffed and said, “I thought I’d be able to see the storms.” Mind you, I didn’t force this. She *asked* to see it, having heard about it on the news. I dragged the scope (a 16.5″ Dobsonian) out just to show her.

    I’ve never shown off anything through the scope since. :(

  35. Quiet_Desperation Says:

    here has been no noticeable upper trend in sunlight for 50 years or more.

    Well, no, it’s been increasing 0.05 percent per decade since the 1970s. Before that we don’t know because you really need satellites to measure with that precision.

    I’m not saying it’s driving GW, but there *is* a small increase. If it has been going on through the 20th century, then it could be a factor if only as something to exacerbate AGW.

    I’m just sayin’. :)

  36. Michael Amato Says:

    In response to Mike Lonergan’s suggestion that I read the April 29th blog, I found the article to be very interesting. A lot more reserach will be needed to determine if the sun has anything to do with global warming. Thanks Mike for giving me the heads up on that interesting blog.

  37. Michael Amato Says:

    I read the April 29th BA blog about weather the sun caused global warming or not. I found it very interesting and there is no doubt that much more reseach is needed to determine if the sun is contributing to global warming

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