STORY WRITTEN FOR CBS NEWS “SPACE PLACE” USED WITH PERMISSION
The red planet’s brush with Comet Siding Spring Sunday was a tighten confront of a best kind for science, a once-in-a-lifetime possibility to investigate a primitive vestige of a solar system’s birth 4.6 billion years ago as it creates a initial and presumably final revisit to a regard of a middle solar system.
Comet C/2013 A1, detected final year during a Siding Spring look-out in Australia, was approaching to pass within about 87,000 miles of Mars during 2:27 p.m. EDT (GMT-4) during a relations quickness 126,000 mph.
An general swift of booster during Mars, dual aspect rovers and 5 orbiters — including a newly-arrived NASA satellite built to investigate a martian atmosphere — had ringside seats for a high-speed flyby. Monitoring from distant were a Hubble Space Telescope and some-more than a half-dozen other spacecraft, along with telescopes during ground-based observatories around a world.
“It’s awesome. It’s such a ridiculously tighten proceed to a planet,” Karl Battams, an astrophysicist and comet consultant during a Naval Research Laboratory in Washington. “We’ve got these illusory booster out during Mars. … It’s an unusual coincidence, and we consider we’re unequivocally propitious to see it. It could good be we don’t see anything like it again in a lifetimes.”
Observers in a southern hemisphere were means to investigate Mars and a comet during tighten approach, though it was not splendid adequate during Earth’s stretch to be manifest to a unaided eye. Complicating a picture, Siding Spring has faded extremely in new weeks as it approached Mars and afterwards perihelion — closest proceed to a intent — on Oct. 25.
“We were unequivocally agreeably astounded during how it was working until about dual weeks ago,” Battams said. “And then, unexpected it started to dump in liughtness most faster than we had anticipated. So now we’re arrange of re-assessing a expectations of a comet and a indication we were judging it against.”
Even so, NASA’s Mars Reconnaissance Orbiter was approaching to have a good view. Commands were uplinked progressing to aim a high-resolution HiRISE camera during a comet in a bid to picture a dim nucleus. The agency’s MAVEN orbiter, that arrived during Mars final month, was staid to demeanour for changes in a martian atmosphere due to interactions with a comet’s dirt tail.
NASA’s Mars Odyssey spacecraft, along with a European Space Agency’s Mars Express orbiter and India’s initial heavenly probe, a Mars Orbiter Mission, or MOM, also lerned their instruments on a comet, as did NASA’s dual aspect rovers, Opportunity and Curiosity.
“The closest a comet has ever approached Earth in complicated annals is about 16 times larger than a stretch of this thing going by Mars,” Battams told CBS News in a phone talk Friday. “It’s going to be a homogeneous of one third a Earth-moon distance. So it’s a unequivocally tighten flyby for some unusual orchestration we’ve got during Mars.
“Now granted, those booster during Mars weren’t designed for looking during comets. But only by fitness and a small bit of adaptation, we should get some unequivocally cold scholarship out of it.”
But it will take time. The Mars booster were not designed for realtime information delivery and it expected will take a scholarship teams hours to several days to accept and routine a information before any pictures, most reduction conclusions, are unveiled.
Siding Spring is of sold seductiveness since it originated in a Oort Cloud, a immeasurable round area of icy waste left over from a strange overflow of gas and dirt that coalesced to form a intent and a audience of planets 4.6 billion years ago.
The Oort Cloud extends from good over a circuit of Pluto median to a nearest star, so distant comets like Siding Spring need a million years or some-more to make a prolonged thrust into a middle solar system.
“We’re going to observe an eventuality that happens maybe once each million years,” Jim Green, executive of NASA’s heavenly scholarship division, pronounced final week. “And this is where a comet entrance from a farthest reaches of a sun’s sobriety will come to a middle partial of a solar system. This comet will fly right in front of a world Mars. Mars will be blanketed in cometary material.”
Last year, another Oort Cloud comet — ISON — generated headlines as it fell toward a tighten flyby of a sun, violation detached and vanishing from perspective as scientists looked on from a stretch regulating sun-watching telescopes in circuit and on a ground.
But Siding Spring is a initial Oort Cloud comet ever celebrated during comparatively tighten operation with complicated instrumentation, giving scientists a possibility to investigate a primitive vestige of a solar nebula.
And they have a lot of questions.
“We’re anticipating a HiRISE instrument on MRO will be means to indeed solve a nucleus, indeed see a altogether figure of a iota widespread over several pixels of a camera,” Battams said. “And that’ll be a initial time we’ve ever seen an Oort Cloud comet nucleus. Then we’ll know how large it is. It could be anywhere from one to 10 kilometers, though that could be off by a cause of dual in any direction. We’re unequivocally not sure.”
Another intent of interest: The comet’s brightness. Comets complicated to date have all done steady trips around a sun, going by cycles of heating and cooling. They tend to be dark.
“This is a primitive intent entrance in, so maybe a aspect will be scarcely contemplative or clamp versa, maybe a aspect will be scarcely dark,” Battams said. “Or maybe it’ll demeanour only like a other ones. But again, it’s a new information indicate from a whole opposite subset of comets.”
Along with a size, scientist wish to investigate a figure to reap clues about how comets shaped in a Oort Cloud. Most comets complicated to date have ranged from potato- or dumbbell-shaped bodies, strange “dirty snowballs.” A comet now being complicated by a European Space Agency’s Rosetta booster facilities dual graphic lobes that give it a entrance of a rubber steep when noticed from a distance.
“We don’t know what leads to a arrangement of those shapes,” Battams said. “Is it that comets are infrequently shaped in uncanny shapes and that’s it? Or maybe as a effect of being in a solar complement for a prolonged time they kind of take on a new figure due to erosion processes.
“From looking during only one hairy small picture of one Oort Cloud iota (Siding Spring), we’re not going to answer a question. But it’s a information point. It’s a initial information indicate we’ve ever had. … If a iota is totally round it arrange of leaves a doubt open ended, though maybe we’ll see another duck-shaped nucleus. Just quite from looking during it it’s going to tell us something.”
Of vital seductiveness is a comet’s communication with a martian atmosphere as a world moves by a outdoor region’s of Siding Spring’s dirt tail. Moving during a relations quickness of 35 miles per second, even little dirt particles will explain appetite in collisions with windy particles.
“MAVEN (is) designed to demeanour during hairy gas clouds in a solar wind,” Battams said. “That’s what Mars is, that’s all MAVEN cares about, that there’s a gas cloud sitting in a solar wind. And it’s got a comet entrance along. It’s smaller, though it’s another gas cloud sitting in a solar wind, and it’s going to see these dual interact.
“It’s an unusual coincidence, and we consider we’re unequivocally propitious to see it. It could good be we don’t see anything like it again in a lifetimes. It could be centuries before something like this comes along. So I’m blissful we’ve got a possibility to get some good observations.”