{"id":16914,"date":"2014-10-19T23:45:41","date_gmt":"2014-10-19T15:45:41","guid":{"rendered":"https:\/\/wp-productionenv-bjg9h2g2bgg5b8aa.southeastasia-01.azurewebsites.net\/news\/comets-flyby-of-mars-a-boon-for-scientists\/"},"modified":"2014-10-19T23:45:41","modified_gmt":"2014-10-19T15:45:41","slug":"comets-flyby-of-mars-a-boon-for-scientists","status":"publish","type":"post","link":"https:\/\/starpath.global\/news\/comets-flyby-of-mars-a-boon-for-scientists\/","title":{"rendered":"Comet\u2019s flyby of Mars a boon for scientists"},"content":{"rendered":"

STORY WRITTEN FOR CBS NEWS \u201cSPACE PLACE\u201d & USED WITH PERMISSION<\/p>\n

\"Artist's
Artist\u2019s concept of comet Siding Spring buzzing Mars. Credit: NASA<\/figcaption><\/figure>\n

The red planet\u2019s brush with Comet Siding Spring Sunday was a close encounter of the best kind for science, a once-in-a-lifetime chance to study a pristine remnant of the solar system\u2019s birth 4.6 billion years ago as it makes its first and possibly last visit to the warmth of the inner solar system.<\/p>\n

Comet C\/2013 A1, discovered last year at the Siding Spring observatory in Australia, was expected to pass within about 87,000 miles of Mars at 2:27 p.m. EDT (GMT-4) at a relative velocity 126,000 mph.<\/p>\n

An international fleet of spacecraft at Mars, two surface rovers and five orbiters \u2014 including a newly-arrived NASA satellite built to study the martian atmosphere \u2014 had ringside seats for the high-speed flyby. Monitoring from afar were the Hubble Space Telescope and more than a half-dozen other spacecraft, along with telescopes at ground-based observatories around the world.<\/p>\n

\u201cIt\u2019s awesome. It\u2019s such a ridiculously close approach to the planet,\u201d Karl Battams, an astrophysicist and comet expert at the Naval Research Laboratory in Washington. \u201cWe\u2019ve got these fantastic spacecraft out at Mars. \u2026 It\u2019s an extraordinary coincidence, and I think we\u2019re very lucky to see it. It could well be we don\u2019t see anything like it again in our lifetimes.\u201d<\/p>\n

Observers in the southern hemisphere were able to study Mars and the comet during close approach, but it was not bright enough at Earth\u2019s distance to be visible to the unaided eye. Complicating the picture, Siding Spring has faded considerably in recent weeks as it approached Mars and then perihelion \u2014 closest approach to the sun \u2014 on Oct. 25.<\/p>\n

\u201cWe were really pleasantly surprised at how it was behaving until about two weeks ago,\u201d Battams said. \u201cAnd then, suddenly it started to drop in brightness much faster than we had anticipated. So now we\u2019re sort of re-assessing our expectations of the comet and the model we were judging it against.\u201d<\/p>\n

Even so, NASA\u2019s Mars Reconnaissance Orbiter was expected to have a good view. Commands were uplinked earlier to aim its high-resolution HiRISE camera at the comet in a bid to image its hidden nucleus. The agency\u2019s MAVEN orbiter, which arrived at Mars last month, was poised to look for changes in the martian atmosphere due to interactions with the comet\u2019s dust tail.<\/p>\n

NASA\u2019s Mars Odyssey spacecraft, along with the European Space Agency\u2019s Mars Express orbiter and India\u2019s first planetary probe, the Mars Orbiter Mission, or MOM, also trained their instruments on the comet, as did NASA\u2019s two surface rovers, Opportunity and Curiosity.<\/p>\n

\u201cThe closest a comet has ever approached Earth in modern records is about 16 times greater than the distance of this thing going by Mars,\u201d Battams told CBS News in a phone interview Friday. \u201cIt\u2019s going to be the equivalent of one third the Earth-moon distance. So it\u2019s a really close flyby for some amazing instrumentation we\u2019ve got at Mars.<\/p>\n

\u201cNow granted, those spacecraft at Mars weren\u2019t designed for looking at comets. But just by luck and a little bit of adaptation, we should get some really cool science out of it.\u201d<\/p>\n

But it will take time. The Mars spacecraft were not designed for realtime data transmission and it likely will take the science teams hours to several days to receive and process the data before any pictures, much less conclusions, are unveiled.<\/p>\n

Siding Spring is of particular interest because it originated in the Oort Cloud, a vast spherical realm of icy debris left over from the original swarm of gas and dust that coalesced to form the sun and its retinue of planets 4.6 billion years ago.<\/p>\n

The Oort Cloud extends from well beyond the orbit of Pluto halfway to the nearest star, so far comets like Siding Spring need a million years or more to make the long plunge into the inner solar system.<\/p>\n

\u201cWe\u2019re going to observe an event that happens maybe once every million years,\u201d Jim Green, director of NASA\u2019s planetary science division, said last week. \u201cAnd this is where a comet coming from the farthest reaches of the sun\u2019s gravity will come to the inner part of our solar system. This comet will fly right in front of the planet Mars. Mars will be blanketed in cometary material.\u201d<\/p>\n

Last year, another Oort Cloud comet \u2014 ISON \u2014 generated headlines as it fell toward a close flyby of the sun, breaking apart and fading from view as scientists looked on from a distance using sun-watching telescopes in orbit and on the ground.<\/p>\n

But Siding Spring is the first Oort Cloud comet ever observed at relatively close range with modern instrumentation, giving scientists a chance to study a pristine remnant of the solar nebula.<\/p>\n

And they have a lot of questions.<\/p>\n

\u201cWe\u2019re hoping the HiRISE instrument on MRO will be able to actually resolve the nucleus, actually see the overall shape of the nucleus spread over several pixels of its camera,\u201d Battams said. \u201cAnd that\u2019ll be the first time we\u2019ve ever seen an Oort Cloud comet nucleus. Then we\u2019ll know how big it is. It could be anywhere from one to 10 kilometers, but that could be off by a factor of two in any direction. We\u2019re really not sure.\u201d<\/p>\n

Another item of interest: The comet\u2019s brightness. Comets studied to date have all made repeated trips around the sun, going through cycles of heating and cooling. They tend to be dark.<\/p>\n

\u201cThis is a pristine object coming in, so maybe the surface will be unusually reflective or vice versa, maybe the surface will be unusually dark,\u201d Battams said. \u201cOr maybe it\u2019ll look just like the other ones. But again, it\u2019s a new data point from a whole different subset of comets.\u201d<\/p>\n

Along with its size, scientist want to study its shape to glean clues about how comets formed in the Oort Cloud. Most comets studied to date have ranged from potato- or dumbbell-shaped bodies, irregular \u201cdirty snowballs.\u201d A comet now being studied by the European Space Agency\u2019s Rosetta spacecraft features two distinct lobes that give it the appearance of a rubber duck when viewed from a distance.<\/p>\n

\u201cWe don\u2019t know what leads to the formation of those shapes,\u201d Battams said. \u201cIs it that comets are sometimes formed in weird shapes and that\u2019s it? Or maybe as a consequence of being in the solar system for a long time they kind of take on a new shape due to erosion processes.<\/p>\n

\u201cFrom looking at just one fuzzy little image of one Oort Cloud nucleus (Siding Spring), we\u2019re not going to answer the question. But it\u2019s a data point. It\u2019s the first data point we\u2019ve ever had. \u2026 If the nucleus is completely spherical it sort of leaves the question open ended, but maybe we\u2019ll see another duck-shaped nucleus. Just purely from looking at it it\u2019s going to tell us something.\u201d<\/p>\n

Of major interest is the comet\u2019s interaction with the martian atmosphere as the planet moves through the outer region\u2019s of Siding Spring\u2019s dust tail. Moving at a relative velocity of 35 miles per second, even tiny dust particles will impart energy in collisions with atmospheric particles.<\/p>\n

\u201cMAVEN (is) designed to look at fuzzy gas clouds in the solar wind,\u201d Battams said. \u201cThat\u2019s what Mars is, that\u2019s all MAVEN cares about, that there\u2019s a gas cloud sitting in the solar wind. And it\u2019s got a comet coming along. It\u2019s smaller, but it\u2019s another gas cloud sitting in the solar wind, and it\u2019s going to see these two interact.<\/p>\n

\u201cIt\u2019s an extraordinary coincidence, and I think we\u2019re very lucky to see it. It could well be we don\u2019t see anything like it again in our lifetimes. It could be centuries before something like this comes along. So I\u2019m glad we\u2019ve got the chance to get some good observations.\u201d<\/p>\n","protected":false},"excerpt":{"rendered":"

STORY WRITTEN FOR CBS NEWS \u201cSPACE PLACE\u201d & USED WITH PERMISSION Artist\u2019s concept of comet Siding Spring buzzing Mars. Credit: NASA The red planet\u2019s brush with Comet Siding Spring Sunday was a close encounter of the best kind for science, a once-in-a-lifetime chance to study a pristine remnant of the solar system\u2019s birth 4.6 billion years ago […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"inline_featured_image":false,"footnotes":"","_links_to":"","_links_to_target":""},"categories":[2],"tags":[3097,4257,367],"class_list":["post-16914","post","type-post","status-publish","format-standard","hentry","category-news","tag-comet","tag-comet-siding-spring","tag-mars"],"acf":[],"_links":{"self":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/16914"}],"collection":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/comments?post=16914"}],"version-history":[{"count":0,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/16914\/revisions"}],"wp:attachment":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/media?parent=16914"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/categories?post=16914"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/tags?post=16914"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}