It’s small and faint and blurry but it’s definitely there… the first comet identified by WISE, NASA’s Wide-field Infrared Survey Explorer.
At the center of the image is a fuzzy red dot. This dot is a 1.2-mile-wide ball of water ice and rock dubbed P/2010 B2 (WISE) – or just Comet WISE for short – that circles the Sun in an elliptical orbit which takes it about 4 times as far as Earth at its farthest to near the distance of Mars at closest.
Comet WISE may have been recently discovered but it’s been around for a while…probably about four and a half billion years. Comets are important to scientists because they are relics from the beginning of the solar system, containing the same ancient materials that was around when the planets were forming. And they are the only places in the inner solar system where water can be found…it’s very likely that comets helped deliver water to Earth in the first place.
“With WISE, we have a powerful tool to find new comets and learn more about the population as a whole. Water is necessary for life as we know it, and comets can tell us more about how much there is in our solar system.”
– JPL’s Amy Mainzer, principal investigator of NEOWISE, a project that will catalog Near Earth Objects found by WISE.
Since mid-December WISE has been scanning the sky in infrared light, allowing scientists to “see” objects that would otherwise – pun intended – be invisible. From the most distant galaxies in their early years to nearby brown dwarfs (and perhaps even a comet or three) the orbiting WISE observatory should hold many more discoveries for us.
Read more about this on the JPL/NASA news site.
Image: NASA/JPL-Caltech/UCLA
Lights in the Dark 
It’s my understanding that comets cannot account for the amount of water on Earth or the isotopic makeup of the water here compared to cometary water. Anybody want to pick this apart with evidence to the contrary? I am willing to stand corrected.
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Could comets have contributed to terrestrial water? There was an early bombardment period, from what I have read, it stands to reason that some of the water – and other stuff – must have arrived via comet. What makes comet water fundamentally different than Earth water? Besides all the critters living in it?
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The ratio of the different isotopes of hydrogen and oxygen that make up different forms of water. Various configurations of “light” and “heavy” water.
Earth-bound water has different ratios of these things than cometary water.
And yes, while we did go through a period of intense bombardment early on, that was basically rocky crud and doubtful sufficient cometary water to give us the surface cover (2/3) and depths (up to two miles in some places). That’s a lot of water.
Methinks until someone can show evidence otherwise, the water here was “placed” here once the planet was cool enough not to burn it all off. Remember, we were molten until about 3.85 billion yrs ago. Not exactly a great place for water to hang around.
Contributed? Yeah, like my spitting into the ocean contributes. Some, but not a whole heck of alot.
Someone way smarter than me can do the calculations of how many comets of what size over what period of time it would take to produce the amount of water on Earth. Freakishly high number.
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It’s over 6 miles in some places…yes, a lot of water. And since everything has to come from somewhere, then it eitehr came from here or out there. Or a combination of both.
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