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

Photogallery Strong Words Start, May End, S. African Xenophobic Attacks

President Jacob Zuma publicly condemned rise in attacks on foreign nationals but critics say leadership has been less than welcoming to foreign residents More

Video Family Waits to Hear Charges Against Reporter Jailed in Iran

Reports in Iran say Jason Rezaian has been charged with espionage, but brother tells VOA indictment has not been made public More

Video Overwhelmed by Migrants, Italy Mulls Action to Stabilize Libya

Amnesty International says multinational concerted humanitarian effort must be enacted to address crisis; decrepit boats continue to bring thousands of new arrivals daily More

Featured Videos

Your JavaScript is turned off or you have an old version of Adobe's Flash Player. Get the latest Flash player.
Are Energy Needs Putting Thailand's Natural Beauty at Risk?i
X
Steve Sandford
April 17, 2015 12:50 AM
Thailand's appetite for more electricity has led to the construction of new dams along the Mekong River to the north and new coal plants near the country's famous beaches in the south. A proposed coal plant in a so-called "green zone" has touched off a debate. VOA's Steve Sandford reports.
Video

Video Are Energy Needs Putting Thailand's Natural Beauty at Risk?

Thailand's appetite for more electricity has led to the construction of new dams along the Mekong River to the north and new coal plants near the country's famous beaches in the south. A proposed coal plant in a so-called "green zone" has touched off a debate. VOA's Steve Sandford reports.
Video

Video Overwhelmed by Migrants, Italy Mulls Military Action to Stabilize Libya

Thousands more migrants have arrived on the southern shores of Italy from North Africa in the past two days. Authorities say they expect the total number of arrivals this year to far exceed previous levels, and the government has said military action in Libya might be necessary to stem the flow. VOA's Henry Ridgwell reports.
Video

Video Putin Accuses Kyiv of ‘Cutting Off’ Eastern Ukraine

Russian President Vladimir Putin, in his annual televised call-in program, again denied there were any Russian troops fighting in Ukraine. He also said the West was trying to ‘contain’ Russia with sanctions. Henry Ridgwell reports on reactions to the president’s four-hour TV appearance.
Video

Video Eye Contact Secures Dog's Place in Human Heart

Dogs serve in the military, work with police and assist the disabled, and have been by our side for thousands of years serving as companions and loyal friends. We love them. They love us in return. VOA’s Rosanne Skirble reports on a new study that looks at the bio-chemical bond that cements that human-canine connection.
Video

Video Ukrainian Volunteers Search for Bodies of Missing Soldiers

As the cease-fire becomes more fragile in eastern Ukraine, a team of volunteer body collectors travels to the small village of Savur Mohyla in the what pro-Russian separatists call the Donetsk Peoples Republic - to retrieve bodies of fallen Ukrainian servicemen from rebel-held territories. Adam Bailes traveled with the team and has this report.
Video

Video Xenophobic Violence Sweeps South Africa

South Africa, long a haven for African immigrants, has been experiencing the worst xenophobic violence in years, with at least five people killed and hundreds displaced in recent weeks. From Johannesburg, VOA’s Anita Powell brings us this report.
Video

Video Sierra Leone President Koroma Bemoans Ebola Impact on Economy

In an interview with VOA's Shaka Ssali on Wednesday, President Ernest Koroma said the outbreak undermined his government’s efforts to boost and restructure the economy after years of civil war.
Video

Video Protester Lands Gyrocopter on Capitol Lawn

A 61-year-old mailman from Florida landed a small aircraft on the Capitol lawn in Washington to bring attention to campaign finance reform and what he says is government corruption. Wednesday's incident was one in a string of security breaches on U.S. government property. Zlatica Hoke reports the gyrocopter landing violated a no-fly zone.
Video

Video Apollo 13, NASA's 'Successful Failure,' Remembered

The Apollo 13 mission in 1970 was supposed to be NASA's third manned trip to the moon, but it became much more. On the flight's 45th anniversary, astronauts and flight directors gathered at Chicago's Adler Planetarium to talk about how the aborted mission changed manned spaceflight and continues to influence space exploration today. VOA’s Kane Farabaugh reports.
Video

Video Badly Burned Ukrainian Boy Bravely Fights Back

A 9-year-old Ukrainian boy has returned to his native country after intensive treatment in the United States for life-threatening burns. Volodia Bubela, burned in a house fire almost a year ago, battled back at a Boston hospital, impressing doctors with his bravery. Faith Lapidus narrates this report from VOA's Tetiana Kharchenko.
Video

Video US Maternity Leave Benefits Much Less Than Many Countries

It was almost 20 years ago that representatives of 189 countries met at a UN conference in Beijing and adopted a plan of action to achieve gender equality around the world. Now, two decades later, the University of California Los Angeles World Policy Analysis Center has issued a report examining what the Beijing Platform for Action has achieved. From Los Angeles, Elizabeth Lee has more.
Video

Video Endangered Hawaiian Birds Get Second Chance

Of the world's nearly 9,900 bird species, 13 percent are threatened with extinction, according to BirdLife International. Among them are two Hawaiian honeycreepers - tiny birds that live in the forest canopy, and, as the name implies, survive on nectar from tropical flowers. Scientists at the San Diego Zoo report they have managed to hatch half a dozen of their chicks in captivity, raising hopes that the birds will flutter back from the brink of extinction. VOA’s George Putic reports.
Video

Video Exhibit Brings Renaissance Master Out of the Shadows

The National Gallery of Art in Washington has raised the curtain on one of the most intriguing painters of the High Renaissance. Mostly ignored after his death in the early 1500s, Italian master Piero di Cosimo is now claiming his place alongside the best-known artists of the period. VOA’s Ardita Dunellari reports.
Video

Video Sidemen to Famous Blues Artists Record Their Own CD

Legendary blues singer BB King was briefly hospitalized last week and the 87-year-old “King of the Blues” may not be touring much anymore. But some of the musicians who have played with him and other blues legends have now released their own CD in an attempt to pass the torch to younger fans... and put their own talents out front as well. VOA’s Greg Flakus has followed this project over the past year and filed this report from Houston.
Video

Video Iran-Saudi Rivalry Is Stoking Conflict in Yemen

Iran has proposed a peace plan to end the conflict in Yemen, but the idea has received little support from regional rivals like Saudi Arabia. They accuse Tehran of backing the Houthi rebels, who have forced Yemen’s president to flee to Riyadh, and have taken over swaths of Yemen. As Henry Ridgwell reports for VOA, analysts say the conflict is being fueled by the Sunni-Shia rivalry between the two regional powers.

VOA Blogs