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.
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

Hostage Crisis Could Divide Japan Over Plans to Boost Military

Japanese Chief Cabinet Secretary Yoshihide Suga said Monday the government is working closely with the Jordanian government to secure the release of remaining Japanese hostage Kenji Goto More

Video Brussels Shaken as New Greek Leader Challenges Europe’s Austerity Drive

Country's youngest ever PM Alexis Tsipras, 40, sworn in Monday and says he will restore dignity to Greece by ending spending cuts More

Multimedia National Geographic Photo Camps Empower Youth

Annual mentoring program's mission is to give young people a voice to tell their own stories through photography More

Featured Videos

Your JavaScript is turned off or you have an old version of Adobe's Flash Player. Get the latest Flash player.
Obama Urges Closer Economic Ties During Historic India Visiti
X
Aru Pande
January 26, 2015 9:33 PM
U.S. President Barack Obama says the United States and India must do better to capitalize on untapped potential in their economic relationship - by removing some of the roadblocks to greater trade and investment. As VOA correspondent Aru Pande reports from New Delhi, Obama spoke after participating in India’s Republic Day celebration.
Video

Video Obama Urges Closer Economic Ties During Historic India Visit

U.S. President Barack Obama says the United States and India must do better to capitalize on untapped potential in their economic relationship - by removing some of the roadblocks to greater trade and investment. As VOA correspondent Aru Pande reports from New Delhi, Obama spoke after participating in India’s Republic Day celebration.
Video

Video US, EU Threaten New Russia Sanctions Over Ukraine

U.S. President Barack Obama has blamed Russia for an attack by Ukrainian separatists that left dozens dead in the port of Mariupol and cast further doubt on the viability of last year’s cease-fire with the Kyiv government. VOA’s Michael Bowman reports from Washington.
Video

Video White House Grapples With Yemen Counterterrorism Strategy

Reports say the U.S. has carried out a drone strike on suspected militants in Yemen, the first after President Barack Obama offered reassurances the U.S. is continuing its counterterrorism operations in the country. The future of those operations has been in question following the collapse last week of Yemen’s government. VOA White House correspondent Luis Ramirez reports.
Video

Video Kerry Warns Against Violence in Nigeria Election

US Secretary of State John Kerry visited Nigeria Sunday in a show of the level of concern within the U.S. and the international community over next month’s presidential election. Chris Stein reports.
Video

Video Zoo Animals Show Their Artistic Sides

The pursuit of happiness is so important, America's founding fathers put it in the Declaration of Independence. Any zookeeper will tell you animals need enrichment, just like humans do. So painting, and even music, are part of the Smithsonian National Zoo's program to keep the animals happy. VOA’s June Soh met some animal artists at the zoo in Washington. Faith Lapidus narrates.
Video

Video Worldwide Photo Workshops Empower Youth

Last September, 20 young adults from South Sudan took part in a National Geographic Photo Camp. They are among hundreds of students from around the world who have learned how to use a camera to tell the stories of the people in their communities through the powerful medium of photography. Three camp participants talked about their experiences recently on a visit to Washington. VOA’s Julie Taboh reports.
Video

Video Saudi, Yemen Developments Are Sudden Complications for Obama

The death of Saudi Arabia's King Abdullah and the collapse of Yemen’s government have cast further uncertainty on U.S. efforts to fight militants in the Middle East and also contain Iran’s influence in the region. VOA White House correspondent Luis Ramirez reports on the new complications facing the Obama administration and its Middle East policy.
Video

Video Progress, Some Areas of Disagreement in Cuba Talks

U.S. and Cuban officials are reporting progress from initial talks in Havana on re-establishing diplomatic ties. U.S. Assistant Secretary of State (for Western Hemisphere Affairs) Roberta Jacobson said while there was agreement on a broad range of issues, there also are some “profound disagreements” between Washington and Havana. VOA State Department correspondent Pam Dockins has the story.
Video

Video US, Japan Offer Lessons as Eurozone Launches Huge Stimulus

The Euro currency has fallen sharply after the European Central Bank announced a bigger-than-expected $67 billion-a-month quantitative easing program Thursday - commonly seen as a form of printing new money. Henry Ridgwell reports for VOA from London on whether the move might rescue the eurozone economy -- and what lessons have been learned from similar programs around the world.
Video

Video Nigerian Elections Pose Concern of Potential Conflict in 'Middle Belt'

Nigeria’s north-central state of Kaduna has long been the site of fighting between Muslims and Christians as well as between people of different ethnic groups. As the February elections approach, community and religious leaders are making plans they hope will keep the streets calm after results are announced. Chris Stein reports from the state capital, Kaduna.
Video

Video As Viewership Drops, Obama Puts His Message on YouTube

Ratings reports show President Obama’s State of the Union address this week drew the lowest number of viewers for this annual speech in 15 years. White House officials anticipated this, and the president has decided to take a non-traditional approach to getting his message out. VOA White House correspondent Luis Ramirez reports.
Video

Video S. Korean Businesses Want to End Trade Restrictions With North

Business leaders in South Korea are calling for President Park Geun-hye to ease trade restrictions with North Korea that were put in place in 2010 after the sinking of a South Korean warship.Pro-business groups argue that expanding trade and investment is not only good for business, it is also good for long-term regional peace and security. VOA’s Brian Padden reports.

Circumventing Censorship

An Internet Primer for Healthy Web Habits

As surveillance and censoring technologies advance, so, too, do new tools for your computer or mobile device that help protect your privacy and break through Internet censorship.
More

All About America

AppleAndroid