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ESA / DLR / FU Berlin (G. Neukum)
Three frames from the series of 104 taken by Mars Express during the Phobos–Jupiter conjunction on 1 June 2011.
Alignments of planets, moons and stars as seen from Earth always get us excited. This close-up view of the Martian moon Phobos lined up with Jupiter ups the ante – it was seen by a spacecraft orbiting Mars.
Phobos is only 23 kilometers wide, whereas Jupiter is 142,000 kilometers across, but at the moment of the alignment on June 1, the European Space Agency's Mars Express orbiter was only 11,389 kilometers away from the lumpy moon. Jupiter was a further 529 million kilometers away.
The High Resolution Stereo Camera on Mars Express was kept fixed on Jupiter for the conjunction, ensuring that the planet remained static in the frame. The operation returned a total of 104 images over a period of 68 seconds, all of them taken using the camera’s super-resolution channel.
These images have been stitched together as a movie, seen below.
On June 1 2001, Mars express watched as Phobos (the inner and larger of Mars' two moons) slipped past distant Jupiter.
Beyond the cool factor of the chance alignment, the observations are helping astronomers refine their knowledge about the orbit of Phobos, which varies with time because of its small mass and extreme proximity to Mars, the Planetary Society's Emily Lakdawalla explains.
Mars Express is studying Phobos to help out the planned Russian Phobos-Grunt mission to land a spacecraft on the moon and snag a sample for return to Earth, which is due for launch in November.
More on Phobos:
- Orbiter gets a fresh 3-D look at Phobos
- Martian moon in spotlight
- Martian moons pictured together for first time
- Phobos likely forged by catastrophic blast
John Roach is a contributing writer for msnbc.com. Connect with the Cosmic Log community by hitting the "like" button on the Cosmic Log Facebook page or following msnbc.com's science editor, Alan Boyle, on Twitter (@b0yle).
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This adds just a little bit more knowledge to the bucket. It should make the Russian's planned landing on Phobos a little bit easier. This is the stuff we (earthlings) should be doing, learning as much as possible about all aspects of outer space. It does help us here on earth.
So, what if the sample returned by Phobos-Grunt is wholly unremarkable other than the fact that it is a sample returned from a Martian moon? I mean, what if nothing in the sample is surprising or "new"?
Then we make a note and go on to the next thing. But what if there is something surprising or new? We really won't know unless we try. Besides we're still finding out new and surprising things at the bottoms of our own oceans and buried under our own cities.
Frankly, I'd be surprised if we do find 'something new'. if, and I mean if, phobos is a captured asteroid, what type of material(s) is it? how commonplace are such? As Fudgie has it, catalogue it and go on to the next tidbit...
So does Jupiter actually appear as a disc from Mars?
Yes. In fact, even in a modest telescope Jupiter shows itself as a disk here on Earth, and we are currently ~twice as far from Jupiter as is Mars.
Michael, question for ya'.
From Earth, we see Venus and Mercury as morning and evening stars. I'm assuming that from Mars, you would see Earth and Venus as morning and evening stars, but could you see Mercury? If so, I assume it would be quite low in the horizon for only a few minutes.
Just curious.
Also, I think it would be cool to see Earth/Moon as a morning or evening stars. (yes, my grammar is incorrect, on purpose)
You are correct about seeing Earth and Venus as morning and evening stars. And also correct about Mercury; it would rise in the Martian sky about 1/2 as high above the local horizon as it does from here on Earth.
I don't know if Luna is bright enough to be naked eye from Mars - I'll play with the idea when I have a few minutes - but my guess is that it would NOT be. However, it would be easy to see Luna from Mars in a small telescope. In fact, Luna can be seen in a modest scope from as far away as Saturn.
Correction - Luna IS visible by naked eye from Mars (assuming that the Martians have eyes), and is the only moon in the Solar System that can be seen from other worlds (other than it's primary).
Luna is surprisingly bright from Mars, reaching up to magnitude 0.9 - comparable to the very brightest stars. (The Earth is much larger, and much more reflective - higher albedo - and so from Mars it's magnitude is -2.5; brighter than any star in the nighttime sky.
Imagine the wonderful mythology that would be born if Mars had a satellite of comparable size and distance between them.
That's a very interesting thought Tony....
When I was checking for naked eye visibility I started wondering about how the science of astronomy may have developed differently for hypothetical Martians, compared to us.
Example - it took Galileo seeing Jupiter's moons in orbit around Jupiter to settle in his mind the truth of Copernicus (the Sun at the center). Martians could see OUR moon without a scope, and so may have been able to figure out celestial mechanics in much less time than it took us.
The Earth and the Moon would be a literal "role model".
Interesting thoughts. But that leads me to think that if Luna were visible from Mars, what would it take to see the Jovian Galilean moons from Mars? What magnitude would they be and what would they need to be to be visible? It seems that on closest distance between Mars and Jupiter that at least Ganymede might be visible. It can be quite bright even with the telescope I had as a teen.
The real excitement will occur when Phobos' orbit decays to the point it reaches the martian atmosphere and then forms a new Martian crater.
I can expect that in the future phobos will be a way station for mars as we shuttle back and forth between our moon and phobos. The russian mission is a critical fist step in that direction if it is what we decide to do. At first glance I would think phobos has caves and caverns, not a bad trait for a moon if you were looking for natural radiation shelters. From our present status, I can expect a robotic fuel depot on phobos before we wise up and put one on our own moon. One of the many fuels in the depots being.....WATER. (not to mention oxygen, nitrogen, yada, yada, yada). Nice article, cool pics!!
I think it would be easier to put a space station in orbit around Mars, rather than try to build one on Phobos. It's too small for any appreciable gravity and any resources would be raw materials and ore, so you would have to build some sort of foundry to extract the minerals.
Space station easier and more cost effective.
I am sure that the Russian mission has much more in mind than bringing back a moon rock. Rumor has it that Phobos is mostly hollow and artificial. Actually more than just rumor. The possibilities of what may be found are exciting!