Curiosity Rover Sees Solar Eclipse On Mars 46
SchrodingerZ writes "Though solar eclipses are fairly common on Earth (much more in the southern hemisphere), yesterday the Mars Curiosity Rover caught sight of a partial solar eclipse in Gale Crater on the Red planet. The martian moon Phobos took a small bite out of the sun on the 37th day (Sol 37) of the rover's martian mission. The Curiosity Rover was able to take a picture of the rare event through a 'neutral density filter that reduced the sunlight to a thousandth of its natural intensity.' This protects the camera from the intense light rays seen during an eclipse or looking directly at the sun. It is possible a short movie of the event could be compiled from the data in the near future. More solar transits of Mars's moon (including the second moon Deimos) are predicted to happen in the days to come."
An eclipse is NOT more common in S. hemishere (Score:5, Interesting)
I don't know where the submitter or editor got his/her eclipse frequency info, but the chances of an eclipse occuring are equal for both hemispheres. If you look at a specific short enough time span, it may appear to favor one hemisphere over another, but the eclipse geometry is symmetrical. There are times that a total eclipse vs. an annular eclipse will favor one hemisphere over another because the distance of the earth from the sun varies, but over any reasonable time scale this will all average out.
Kurt
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Re:An eclipse is NOT more common in S. hemishere (Score:4, Funny)
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http://eclipse.gsfc.nasa.gov/SEsaros/image/Saros145-big.JPG
it seems to take just over 100 years to go from grazing the top of the earth (1891) to peaking in central europe (lat 47-ish, sin(47)=0.73) and another just over 50 years to peak in saudi arabia (lat 25-ish, sin(25)=0.42). Alas the latitude doesn't take into account the tilt of the earth, so it's hard to extrapolate to find out when the eclipse will be centred at the equator, a
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"Saros 136 will produce 71 eclipses over 1262 years in the following order: 8 partial, 6 annular, 6 hybrid, 44 total, and 7 partial. "
From: http://eclipse.gsfc.nasa.gov/SEsaros/image/SEpanoramaGvdB-big.JPG
it seems that most cycles have about 50 annular/hybrid/total eclipses, so that would be 900 years of activity.
Eclipses viewed from MER (Score:4, Informative)
Every location on Mars gets an eclipse by both Phobos and Deimos twice a year.
It's nice that Curiosity is looking into the sky, but it's worth pointing out that this is by no means the first time we've watched eclipses from the surface of Mars-- we've caught both Phobos and Deimos transiting the sun, from both of the the MER rovers:
Spirit http://www.lpl.arizona.edu/~lemmon/mer/phobos_transit_104a.gif [arizona.edu]
and Opportunity http://www.lpl.arizona.edu/~lemmon/mer/Phobos_Sol45B.gif [arizona.edu]
A nice page from 2006 is here: http://www.bibalex.org/eclipse2006/MarsEclipses.htm [bibalex.org]
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Every location on Mars gets an eclipse by both Phobos and Deimos twice a year.
You can't even see Phobos from the polar regions (> 70 degrees or so) -- it's always below the horizon -- so how can it eclipse anything?
And the morons mod your crap to +4... gotta love /.
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You can't even see Phobos from the polar regions (> 70 degrees or so) -- it's always below the horizon -- so how can it eclipse anything?
OK, good point. You get transits (eclipses) at every place on the surface of Mars from which you can see the moons.
No transits of Phobos from locations where you can't see Phobos.
Re:Eclipses viewed from MER (Score:5, Informative)
A nice page from 2006 is here: http://www.bibalex.org/eclipse2006/MarsEclipses.htm [bibalex.org]
Every location on Mars gets an eclipse by both Phobos and Deimos twice a year.
Dude, re-read your link.
A nice page from 2006 is here: http://www.bibalex.org/eclipse2006/MarsEclipses.htm [bibalex.org]
"The two moons pass between Mars and the Sun so frequently that solar eclipses would not be a rare event to the Martian observer. Phobos eclipses the Sun 1,300 times a year; but the eclipses are so brief, lasting about 20 seconds!"
"As the orbits of Phobos and Deimos lie near the plane of Mars' equator, and due to the proximity of the moons to Mars, Phobos (and its eclipses) cannot be seen above Martian latitude 69, and Deimos (and its eclipses) cannot be seen above latitude 82."
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Every location on Mars gets an eclipse by both Phobos and Deimos twice a year.
No, only at the equator [agu.org] :
There is a narrow band, centered on the equator of Mars, within which every point is eclipsed at least once during each semiannual eclipse season. Outside that band, the density of coverage decreases slowly with increasing distance from the equator, until the limiting latitudes are reached.
BTW, a surface transit (that is a more appropriate proper term, as neither moon ever fully eclipses the Sun) was also observed by the VIking Lande 1 [nasa.gov] in the 1970's.
And for the Earth solar eclipses, over an 18.6 year cycle, are equally likely in either terrestrial hemisphere.
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Well the introductory sentence is a all wrong anyway, Currently it starts off discussing how common eclipses are on Earth, which makes no sense at all. What does the the frequency of eclipses on Earth have to do with anything, unless it is used as a comparison to those on Mars? But that comparison never appears. We still don't know how common they are on Mars,
So perhaps it should say
"Though solar eclipses are fairly common on Mars (much more in the southern hemisphere)......"
Mar's moon? (Score:5, Funny)
What is this Mar they are speaking about?
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Andrew Marr
FTFY, and spoiled the joke too I guess.
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Actually, it's "Mars's". Just because it ends in 's' doesn't mean you treat it like a plural when making it possessive.
Re:Mars' not Mar's (Score:4, Interesting)
Actually, it does, depending upon whose style manual you are using. In some style manuals, proper names ending with a single "s" take the possessive as "s'" and not "s's" for reasons of euphony; but in all style manuals, proper names ending with a double "ss" take the possessive as "ss's."
Eclipse, or transit? (Score:5, Insightful)
I thought we only called it an eclipse when the occluding body is of comparable angular diameter? Phobos is something like half the solar diameter (depending on latitude); I'd call it a transit.
Re:Eclipse, or transit? (Score:5, Funny)
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Eclipse : nearer body covers the other body
Partial eclipse : the body could cover the other body, but doesn't (i.e., it nicks it).
Transits : the nearer body is not big enough to cover the other body. Phobos and Deimos, as seen from the surface of Mars, fall in this category.
The angular size of the Moon is so close to that of the Sun, as seen from the Earth, that a special kind of transit is possible, which has a special term - an annular eclipse, where a thin ring of the Sun's surface is still visible (bec
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Yes, properly these are transits, not partial eclipses.
Moon? (Score:1)
That's no moon...
PHOBOS (Score:2)
itty bitty moons (Score:3)
Aren't *all* eclipses of Mars partial?
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relevant:
http://allaboutjeff.wordpress.com/2009/05/03/the-distance-of-the-moon-by-italo-calvino/ [wordpress.com]
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Depends on whether you consider an annular eclipse to be partial or not.
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yep, wouldn't want to test out the instruments before getting to the good place to make sure they are in good working order. Also who says the rover paused for more than a few seconds to tale this shot. Adjust arm while moving, pause to take shot, continue moving while parking arm again.
In Soviet Russia... (Score:2)