From NASA JPL: NASA Mars Rover Views Eclipse of the Sun by Phobos
PASADENA, Calif. – Images taken with a telephoto-lens camera on NASA’s Mars rover Curiosity catch the larger of Mars’ two moons, Phobos, passing directly in front of the sun — the sharpest images of a solar eclipse ever taken at Mars.
Phobos does not fully cover the sun, as seen from the surface of Mars, so the solar eclipse is what’s called a ring, or annular, type.
This set of three images shows views three seconds apart as the larger of Mars’ two moons, Phobos, passed directly in front of the sun as seen by NASA’s Mars rover Curiosity. Curiosity photographed this annular, or ring, eclipse with the telephoto-lens camera of the rover’s Mast Camera pair (right Mastcam) on Aug. 17, 2013, the 369th Martian day, or sol, of Curiosity’s work on Mars. Image credit: NASA/JPL-Caltech/Malin Space Science Systems/Texas A&M Univ. › Full image and caption
A set of three frames from Curiosity’s Mast Camera (Mastcam), taken three seconds apart as Phobos eclipsed the sun, is at http://www.jpl.nasa.gov/spaceimages/details.php?id=PIA17356 .
The images are the first full-resolution frames downlinked to Earth from an Aug. 17, 2013, series. The series may later provide a movie of the eclipse. Curiosity paused during its drive that day to record the sky-watching images.
“This event occurred near noon at Curiosity’s location, which put Phobos at its closest point to the rover, appearing larger against the sun than it would at other times of day,” said Mark Lemmon of Texas A&M University, College Station, a co-investigator for use of Curiosity’s Mastcam. “This is the closest to a total eclipse of the sun that you can have from Mars.”
Observations of the Martian moons, Phobos and Deimos, by Curiosity and by the older, still-active Mars rover Opportunity are helping researchers get more precise knowledge of the moons’ orbits. During the Aug. 17 observation, the position of Phobos crossing the sun was a mile or two (two or three kilometers) closer to the center of the sun’s position than researchers anticipated.
Lemmon said, “This one is by far the most detailed image of any Martian lunar transit ever taken, and it is especially useful because it is annular. It was even closer to the sun’s center than predicted, so we learned something.”
NASA’s Jet Propulsion Laboratory, a division of the California Institute of Technology, manages the Mars Science Laboratory Project for NASA’s Science Mission Directorate, Washington. JPL designed and built the project’s Curiosity rover.
Malin Space Science Systems, San Diego, built and operates the Mastcam instrument and two other instruments on Curiosity.
More information about Curiosity is online at http://www.jpl.nasa.gov/msl , http://www.nasa.gov/msl and http://mars.jpl.nasa.gov/msl/ . You can follow the mission on Facebook at http://www.facebook.com/marscuriosity and on Twitter at http://www.twitter.com/marscuriosity .
I remember my mind being blown as a kid when I learned that
Phobos’ orbital period is less than the Martian day. Thus, it
would rise in the Martian equivalent of the west.
gopal panicker says:
August 30, 2013 at 6:19 am
Paul Westhaver says:
August 30, 2013 at 7:38 am
Instead of griping about it, provide evidence. Oh, okay, I’ll do it for you. First, you should have noted the main body of the article includes:
Next, check a dictionary. I didn’t see a good astronomical dictionary, and ordinary ones aren’t very useful about “transit”:
http://dictionary.reference.com/browse/transit
A doesn’t apply, C is uninformative, B is Earth-centric, but can be stretched, but on its face, Luna, Deimos, and Phobos can’t transit, clearly bogus.
Wikipedia does better:
I figured there would be a vagueness: “hiding a small part of it, as seen by an observer at some particular vantage point.”
Sticking with Wikipedia, eclipse is:
This is also vague. Clearly “obscured” does no mean “covered” as that would rule out partial and annular eclipses. However, we admit to a “partial solar eclipse” if any part of the Sun is obscured by Luna, and Phobos did obscure part of the Sun. Also, the penumbral shadow cast by Phobos tracked across part of Mars. Therefore “a planet moving into the shadow cast by one of its moons” applies.
So, I claim it was probably a transit, probably not an occultation, and definitely an eclipse, a partial eclipse, and an annular eclipse. Which brings to mind:
🙂
@Pamela, your name may be ‘gray’, but that vignette was anything but. Thank you for a lovely start to my weekend.
@Carsten Arnholm, Dudley Horscroft –
Yes, I should think the Earth’s atmosphere would give quite an impression of an annular eclipse, especially if the Earth was centered in front of the Sun – it would be brilliantly illuminated – but that isn’t a true annular eclipse, not like the one we saw here in Chico, California a few months ago
Eclipse; what eclipse ?
Looks like a transit of Phobos to me.
Well they all are “roughly” spherical.
Absolutely nothing in the universe is spherical, satisfying the Cartesian equation:-
x^2 + y^2 + z^2 = a^2
Or the polar equation:- a = const.
Nor ANY other equation either. ALL of mathematics is pure fiction.
Hey! Phobos really IS shaped like a potato!
Chad Wozniak wrote:
“Yes, I should think the Earth’s atmosphere would give quite an impression of an annular eclipse, especially if the Earth was centered in front of the Sun…”
I, too, would go happily with the atmospheric solution to Dudley’s puzzle, but also throw in the possibility of the corona being included as part of the Sun (which, of course, it is). I imagine the red refracted light surrounding the Earth with the solar corona behind to be quite a sight.
Speaking of sights – when I observed the transit of Venus back in 2004, just as the planet appeared to touch the Sun its atmosphere lit up as an entire ring with refracted sunlight. Made the hairs stand up on the back of my neck in a very unscientific manner.
If Venus had Earth’s atmosphere, what would conditions there be like?
James Schrumpf says:
August 30, 2013 at 3:53 pm
If Venus had Earth’s atmosphere, what would conditions there be like?
//////////////////////////
Like in Florida on a hot August afternoon – and then some…
Diemos occulted by Phobos in a 55sec time lapse taken by Curiosity on 1 August 2013.
The 55sec transit was compressed to 15sec. I wonder why they bothered ?
http://www.youtube.com/watch?v=DaVSCmuOJwI#t=19 (JPL)
“If Venus had Earth’s atmosphere, what would conditions there be like?”
Venus has no significant magnetic field, so in very short order all the water vapour would be removed by the solar wind (hydrogen and oxygen split, hydrogen whisked away). In longer order, because Venus has no plate tectonics, it is thought the planet might “boil over” every so often (geologically speaking) where the entire surface becomes molten. This would release vast amounts of CO2 into the atmosphere.
So, Venus being Venus, the answer to your question might be – eventually – like Venus.
A more complicated scenario might be to consider what conditions would be like if the Earth replaced Venus in its orbit. Hmmm, superheated, expanded greenhouse atmosphere of water vapour leading to eventual hydrogen loss (despite magnetic field)? With water removed, plate tectonics stop and planet boils over releasing vast amounts of CO2? So, eventually, like Venus?
Interestingly, on Venus today, at the level in the atmosphere where the pressure is the same as on Earth, the temperature is only about 10C higher. This despite the planet being much closer to the Sun and the atmosphere being almost entirely CO2 (plus being above deep levels at very high temps). With an oxygen mask and some serious Sun-block, you could probably walk around (on a floating platform) in shirt-sleeves.
Here’s a pic up close of Phobos, anyone know what caused those grooves?
http://www.edb.utexas.edu/missiontomars/images/phobos_vik1_big.jpg
From Keith Minto on August 30, 2013 at 4:55 pm:
Because by throwing out nearly 3 out of every 4 frames, they greatly reduced the work when they photoshopped out the support cables, duh.
Forget the corona. You would not see it due to the bright red glare of the refracted sunlight in the Earth’s atmosphere, which has to look like a perfect very bright ring (assuming the Sun centered behind the Earth).
Under such conditions, we have a lunar eclipse as seen from Earth. Then the Moon might look like it did when I saw it October 28, 2004
http://arnholm.org/astro/moon/oslo1_webcam_Oct28_04_21_50.jpg
(geoetry not perfect in this case, but still)
“Forget the corona. You would not see it due to the bright red glare of the refracted sunlight in the Earth’s atmosphere, which has to look like a perfect very bright ring (assuming the Sun centered behind the Earth).”
I’m not convinced, Carsten. I’ve seen a lot of lunar eclipses over the years, and in some the moon gets very dark indeed (with our night sky suitable for some deep sky observing). In those circumstances I don’t think the red ring would be especially bright. Will look into it some more when I get back home from work.
There are images of solar eclipses from near the Moon.
The best is a movie made by Japanese satellite kaguya, of Earthrise during a partial eclipse http://space.jaxa.jp/movie/20090218_kaguya_movie01_j.html . It was slow to load, but played fine. It is color, but overexposed so you can’t see the sunrise/sunset colors.
http://science1.nasa.gov/science-news/science-at-nasa/2009/25feb_kaguyaeclipse/ has links to that and also the first photo, from Surveyor 3, and a link to a photo from Apollo 12’s return trip.
PJF, atmospheric scientists look forward to lunar eclipses as a means to gauge how much dust is in the atmosphere. The darkest eclipses are a while after large volcanic eruptions. From the photos I just posted, I was reminded that the bright ring is very narrow – just the height of the dirty part of the atmosphere. There’s not much illumination there and lunar soil is dark to begin with (but at least the full moon increased albedo effect is in full play).
Mike Bromley the Kurd says:
August 30, 2013 at 8:36 am
You said it Mike Bromley.
The “Right Stuff” NASA doesn’t work with “If…but…maybe” logic. When you send a manned mission into space there’s no room for error bands. If you’re not right on the button then people die.
Compare that with the “Wrong Stuff” NASA.
When we get to terraforming Mars, one of the first things will have to be lowering of Phobos’ orbit so it can do proper solar eclipses.
No, no – we need to move Phobos out and use it as the anchor for a space elevator. Read Kim Stanley Robinson’s Red Mars. Or is it in Green Mars?