News / Science & Technology

Astronomers Awaiting Comet ISON's Year-End Spectacular

Comet ISON is shown in this NASA handout image photographed by the Hubble telescope on April 10, 2013.Comet ISON is shown in this NASA handout image photographed by the Hubble telescope on April 10, 2013.
x
Comet ISON is shown in this NASA handout image photographed by the Hubble telescope on April 10, 2013.
Comet ISON is shown in this NASA handout image photographed by the Hubble telescope on April 10, 2013.
TEXT SIZE - +
Rick Pantaleo
Excitement has been growing in recent months over the approach of Comet ISON.  Like other comets, this chunk of rock and ice is following a long, elliptical orbit around the Sun, and like other comets, when it nears the Sun later this year, its trailing stream of dust and vapor will catch the sunlight and become a long, luminous, tail. Many astronomers are predicting that when this celestial traveler sweeps by us later this year, it could turn out to be ‘the comet of the century.’
 
Comet ISON was discovered on September 21, 2012, by two amateur astronomers in Russia, using a reflecting telescope at an observatory of the International Scientific Optical Network. The stargazers then named the new comet after the network’s acronym, ISON. It’s officially known as C/2012 S1.
 
Dennis Bodewits, an astronomer at the University of Maryland who has been keeping a close eye on ISON, explains that excitement about its approach has been building as observers worked out the comet’s trajectory:
 
“We started seeing Comet ISON by the end of last year, when it was really far away from Earth and the Sun, and it was already really clearly active. And people started reconstructing its orbit and figuring out what was up with this comet. If you do this and you reason forward in time, we think that this comet will be really bright by the time it gets close to the Sun.”
 
Bodewits and other astronomers following ISON recently used resources such as NASA’s Hubble Space Telescope and the Swift satellite to get a good look at the comet as it makes its way through our solar system. Bodewits says he was especially eager to learn how big the comet’s nucleus is.
 
“And this is important to know [since it’s an indication of] whether it will survive its close approach to the Sun.  If you have a very big object, it’s more likely that some of it will remain once it flies by the Sun.  The reason why you have to do that now is because as it becomes more active there’s this giant cloud of dust and gas that you cannot see through and you cannot see the nucleus directly. This is a problem that we always have with comets.”
 
So how big is ISON’s nucleus? Bodewits surmises that it’s not very large.
 
“What Hubble found is that the comet was smaller than they could see. That means that it’s at most four kilometers, or two and a half miles, in diameter, which means that it’s relatively small.”
 
A ‘Sun-grazing comet’

ISON is classified as a ‘Sun-grazing comet,’ since its calculated elliptical trajectory will bring it very close to the Sun before it is flung back into deep space by the Sun’s gravity.
 
“It’s a fresh comet from the Oort clouds, where comets reside and when this orbit was done it was also clear that this comet will get within two solar radii off the surface of the Sun, which is really close to the Sun.”
 
Since ISON will be flying so close to the Sun, Bodewits says there are concerns that the powerful gravitational forces could cause the comet to break apart.
 
“As for now we simply don’t know what will happen. And, that’s one of the things that make this comet so unique. We never see comets that appear this far away. We can then follow it all the way in until it gets so close to the Sun and we’re all speculating on whether it will survive or not or break up as it does. So, this is another opportunity for us to learn more about the internal structure of comets.”
 
Astronomers believe ISON is going to put on a spectacular display this November, possibly becoming so bright that it will be visible in the daytime sky. Bodewits says ISON is already gearing up for the show:
 
“If a comet is very active, which means it produces a lot of gas, it will kick up a lot of dust and that dust then makes it a spectacular comet. ISON is far away from the Sun, but it is already kicking up a lot of dust, both literally and figuratively.”
 
The excitement over ISON follows a number of recent comet sightings, each of which generated lots of advance media buzz, but few of which lived up to the hype. One exception came six years ago with Comet McNaught, which was also known as the Great Comet of 2007.  Astronomers say the comet was the brightest that had been seen in over 40 years.
 
But then there were disappointments, such as Comet Kohoutek back in 1973, which  had been hyped by the media as the "comet of the century." Kohoutek sputtered out after its arrival and was considered by most to be a total let-down; possibly because it started to break up during a close approach to the Sun just before its Earth flyby.  Comet Kohoutek became the butt of many comedians’ jokes back then.
 
And Halley’s Comet, one of the best-known and well-documented celestial visitors, returned to much fanfare in 1986, but because its orbit took it twice as far from Earth as during its celebrated 1910 visit, Halley’s appeared only dimly in the night sky.
 
Will Comet ISON live up to the hype now building for its arrival later this year, when it could be visible in many part of the world?  We’ll just have to wait and see whether ISON will be "the comet of the century," or just another chunk of ice and rock slipping quietly through our cosmic neighborhood.

You May Like

Multimedia Anti-Keystone XL Protests Continue

Demonstrators are worried about pipeline's effect on climate change, their traditional way of life, health and safety More

Thailand's Political Power Struggle Continues

Court gave Prime Minister Yingluck Shinawatra until May 2 to prepare her defense over abuse of power charges but uncertainty remains over election timing More

Malaysia Plane Search Tests Limits of Ocean Mapping Technology

Expert tells VOA existing equipment’s maximum operating depth is around 6 kilometers as operation continues on ocean bed for any trace of MH370 More

Featured Videos

Your JavaScript is turned off or you have an old version of Adobe's Flash Player. Get the latest Flash player.
Pet Kangaroo Helps Spread Environmental Messagei
X
Penelope Poulou
April 22, 2014 5:53 PM
Children’s author Julia Heckathorn travels the world to learn about different ecosystems and endangered animals. She pours her knowledge into children’s books, hoping the next generation will right the environmental wrongs of our times. As in many children's books, the main character in Heckathorn's stories is an animal. Unlike those other characters, though, this one is real - a kangaroo, that lives in the author’s backyard. VOA’s Penelope Poulou has more.
Video

Video Pet Kangaroo Helps Spread Environmental Message

Children’s author Julia Heckathorn travels the world to learn about different ecosystems and endangered animals. She pours her knowledge into children’s books, hoping the next generation will right the environmental wrongs of our times. As in many children's books, the main character in Heckathorn's stories is an animal. Unlike those other characters, though, this one is real - a kangaroo, that lives in the author’s backyard. VOA’s Penelope Poulou has more.
Video

Video Pro-Russian Separatists Plan 'Federalization Referendum' in Eastern Ukraine

Pro-Russian separatists in eastern Ukraine say they plan to move forward next month with a referendum vote for greater autonomy, despite the Geneva agreement reached with Russia, the U.S. and Ukraine to end the political conflict. VOA's Brian Padden reports from the city of Donetsk in Eastern Ukraine.
Video

Video Pope Francis Hopes Dual Canonizations Will Reconcile Church

On April 27, two popes - John the XXIII and John Paul II - will be made saints in a ceremony at St. Peter’s Square. VOA religion correspondent Jerome Socolovsky says the dual canonization is part of the current pope’s program to reconcile liberals and conservatives in the Roman Catholic Church.
Video

Video In Capturing Nature's Majesty, Film Makes Case for Its Survival

French filmmaker Luc Jacquet won worldwide acclaim for his 2005 Academy Award-winning documentary "March of the Penguins". Now Jacquet is back with a new film that takes movie-goers deep into the heart of a tropical rainforest - not only to celebrate its grandeur, but to make the case for its survival. VOA's Rosanne Skirble reports.
Video

Video Boston Marathon Bittersweet for Many Runners

Monday's running of the Boston Marathon was bittersweet for many of the 36,000 participants as they finished the run that was interrupted by a double bombing last year. Many gathered along the route paid respect to the four people killed as a result of two bombings near the finish line. VOA's Carolyn Presutti returned to Boston this year to follow two runners, forever changed because of the crimes.
Video

Video International Students Learn Film Production in World's Movie Capital

Hollywood - which is part of Los Angeles - is the movie capital of the world, and many aspiring filmmakers go there in hopes of breaking into the movie business. Mike O'Sullivan reports that regional universities are also a magnet for students who hope to become producers or directors.
Video

Video Pacific Rim Trade Deal Proves Elusive

With the U.S.-led war in Iraq ended and American military involvement in Afghanistan winding down, President Barack Obama has sought to pivot the country's foreign policy focus towards Asia. One aspect of that pivot is the negotiation of a free-trade agreement among 12 Pacific Rim nations. But as Obama leaves this week on a trip to four Asian countries he has found it very difficult to complete the trade pact. VOA's Ken Bredemeier has more from Washington.
Video

Video Autistic Adults Face Housing, Job Challenges

Many parents of children with disabilities fear for the future of their adult child. It can be difficult to find services to help adults with disabilities - physical, mental or emotional - find work or live on their own. The mother of an autistic boy set up a foundation to advocate for the estimated 1.2 million American adults with autism, a developmental disorder that causes communication difficulties and often social difficulties. VOA's Faiza Elmasry reports.
AppleAndroid