Mountain-sized comet to pass close to Mars

CAPE CANAVERAL, Fla. — The heavens are hosting an event this weekend that occurs once in a million years or so.

A comet as hefty as a small mountain will pass mind-bogglingly close to Mars on Sunday, approaching within 87,000 miles at a speed of 126,000 mph.

NASA’s five robotic explorers at Mars — three orbiters and two rovers — are being repurposed to witness a comet named Siding Spring make its first known visit to the inner solar system. So are a European and an Indian spacecraft circling the red planet.

The orbiting craft will attempt to observe the incoming iceball, then hide behind Mars for protection from potentially dangerous dusty debris in the comet tail.

Shielded by the Martian atmosphere, the Opportunity and Curiosity rovers may well have the best seats in the house, although a dust storm on Mars could obscure the view.

“We certainly have fingers crossed for the first images of a comet from the surface of another world,” said NASA program scientist Kelly Fast.

Spacecraft farther afield, including the Hubble Space Telescope, already are keeping a sharp lookout, as are ground observatories and research balloons.

“We’re getting ready for a spectacular set of observations,” said Jim Green, head of NASA’s planetary science division.

Named for the Australian observatory used to detect it in January 2013, Siding Spring will approach Mars from beneath and zoom right in front Sunday afternoon, Eastern Time.

On Earth, the best viewing, via binoculars or telescope, will be from the Southern Hemisphere — South Africa and Australia will be in prime position. In the Northern Hemisphere, it will be difficult to see Siding Spring slide by Mars.

The comet — with a nucleus estimated to be at least a half-mile in diameter — hails from the Oort Cloud on the extreme fringe of the solar system. It formed during the first million or two years of the solar system’s birth 4.6 billion years ago and, until now, ventured no closer to the sun than perhaps the orbits of Jupiter, Saturn, Uranus or Neptune. It comes around every one or more million years.

It will be the first Oort Cloud comet to be studied up close in detail.

For comparison, the flyby distance of 87,000 miles is about one-third of the way from here to the moon. Siding Spring’s tail could extend from Earth all the way to our moon. Its gaseous coma, the fuzzy head surrounding the nucleus, might stretch halfway to the moon.

No comet has come anywhere near this close to Earth in recorded history.

“We can’t get to an Oort Cloud comet with our current rockets … so this comet is coming to us,” said Carey Lisse, senior astrophysicist at Johns Hopkins University’s applied physics laboratory.

By studying Siding Spring’s composition and structure, scientists hope to learn more about how the planets formed, according to Lisse. Scientists also are keen to spot any changes to the comet or Mars due to the close approach. NASA’s newly arrived Maven spacecraft, for instance, will compare the upper atmosphere before and after it passes.

“Think about a comet that started its travel probably at the dawn of man and it’s just coming in close now,” Lisse said. “And the reason we can actually observe it is because we have built satellites and rovers. We’ve now got outposts around Mars.”

Scientists initially worried the spacecraft orbiting Mars would be at considerable risk from the comet’s massive trail of dust.

The nucleus itself poses no danger of impact. But the particles in the tail, hurtling through space at 126,000 mph could fry electronics, puncture fuel lines, or destroy computers, transmitters or other vital spacecraft parts.

As Siding Spring’s path became clearer, the threat level was deemed minimal. Still, space agencies are taking no chances. They’re employing the “duck and cover” strategy.

NASA’s three orbiters — Mars Odyssey, Mars Reconnaissance Orbiter and newcomer Maven — will be behind the red planet at the time of peak danger. That’s a 20-minute-or-so period approximately 1½ hours after the closest approach by the comet’s nucleus.

The European Space Agency also shifted the orbit of its Mars Express as did India for its Mars Orbiter Mission, or MOM, the country’s first interplanetary spacecraft that, like NASA’s Maven, arrived last month.

The precautions are prudent, said University of Maryland senior research scientist Tony Farnham, who led a hazard-analysis team.

“Comets are complex beasts and don’t always live up to our predictions,” Farnham said in an email Wednesday. “If you don’t want surprises, then don’t study comets.”

It will take at least a few days to obtain and analyze the best spacecraft data; but images made from Earth should be forthcoming pretty quickly.

Siding Spring should pass closest to the sun six days after its Mars flyby, then swing back out, bidding goodbye, for at least another million years.

ad-high_impact_4
News
Vegas Homeless Remembered
Las Vegas vigil remembers 179 homeless people who died over the past year in Clark County. (David Guzman/Las Vegas Review-Journal)
A look inside Tesla’s Nevada Gigafactory
Tesla's Gigafactory east of Reno produces the batteries that fuel the company's electric cars. Production has created more than 7,000 jobs, and the campus that includes one of the largest buildings in the world is expected to triple in size by the time it is completed. Tesla Vice President Chris Lister leads a tour of the facility. (Bill Dentzer/Las Vegas Review-Journal)
Garnet Interchange Ribbon Cutting
The Nevada Department of Transportation celebrated the completion of the $63 million I-15-US 93 Garnet Interchange project. The project includes a modified diverging diamond interchange and a 5-mile widening of US 93.
State Foresters Hunt for Record Trees
Urban foresters from the Nevada Division of Forestry hunt for record setting trees.
Rick Davidson directs NFR satellite feed
Rick Davidson directs the Wrangler NFR's live satellite feed from a production trailer outside the Thomas & Mack Center. (Patrick Everson)
Scott Boras, Bryce Harper's agent, speaks to media at baseball's winter meetings
Baseball agent Scott Boras updates media on the contract negotiations of his client Bryce Harper during baseball's winter meetings at Mandalay Bay in Las Vegas, Nevada, on Dec. 12, 2018. (Ron Kantowski/Las Vegas Review-Journal)
Achievement School District
The achievement district faced strong opposition from traditional schools back in its beginnings in 2016. But with schools like Nevada Rise and Nevada Prep, it's slowly and steadily growing. Amelia Pak-Harvey/Las Vegas Review-Journal
Fresno State QB on record-breaking receiver
Fresno State quarterback Marcus McMaryion talks record-setting receiver KeeSean Johnson. Video by Mark Anderson/Las Vegas Review-Journal
The annual 'Shop with a Cop' event at Target
This year’s "Shop with a Cop" event gave about 40 children the chance to shop at Target alongside a North Las Vegas Police officers. Bizuayehu Tesfaye/Las Vegas Review-Journal @Bizutesfaye
Melvin Dummar dead at 74
Melvin Dummar has died at 74. Dummar was famous for claiming to have saved Howard Hughes in a Nevada desert in 1967. Dummar claimed to have been left $156 million in Hughes’ will. The will mysteriously appeared after Hughes’ death in 1976. It was dismissed as a fake two years later. Dummar never saw a dime of the billionaire's fortune. Dummar died Saturday in Nye County.
Officer-involved shooting in Nye County
The Nye County Sheriff's Office gives information about a shooting in Pahrump on Thursday night after a man began firing shots outside of his home. (Nye County Sheriff's Office)
Law Enforcement Active Shooter Training Exercise
Multiple Las Vegas Valley law enforcement agencies held an active shooter drill at the Department of Public Safety’s Parole and Probation office on December 6, 2018. Officials set up the training exercise to include multiple active shooters, a barricaded suspect and multiple casualties. (Katelyn Newberg/ Las Vegas Review-Journal)
Public memorial service for Jerry Herbst
Archiving effort hits milestone at Clark County Museum
The Clark County Museum catalogs the final item from the bulk of Route 91 Harvest festival artifacts. (John Przybys/Las Vegas Review-Journal)
Pearl Harbor survivor Edward Hall talks about his memories of Dec. 7, 1941
U.S. Army Corps Edward Hall, a 95-year-old survivor of Pearl Harbor talks about his memories of that horrific day. Bizuayehu Tesfaye/Las Vegas Review-Journal @bizutesfaye
Final Route 91 Harvest festival remembrance objects catalogued at Clark County Museum
The last of the more than 17,000 items left at the makeshift memorial near the Las Vegas sign after the Oct. 1 shootings have been catalogued at the Clark County Museum in Las Vegas. The final item was a black-and-white bumper sticker bearing "#VEGASSTRONG. An additional 200 items currently on display at the museum will be catalogued when the exhibit comes down. (K.M. Cannon Las Vegas Review-Journal)
Dozier execution timeline
Scott Dozier was set to be executed July 11, 2018, at the Ely State Prison. Judge Elizabeth Gonzalez delayed the execution.
Grand Jury Indicts Constable for theft
A Clark County grand jury indicted Henderson Constable Earl Mitchell. A Las Vegas Review-Journal investigation prompted the criminal probe. The newspaper found Mitchell wrote himself thousands in checks, took out cash at ATMs and traveled on county funds. He faces four felony counts of theft and a county of public misconduct. Mitchell and his attorney could not be reached for comment.
93-year-old WWII veteran arrested during visit to VA hospital
Dr. S. Jay Hazan, 93, a World War II veteran, talks about his arrest during his visit to VA hospital on Friday, Nov. 30. (Erik Verduzco Las Vegas Review-Journal @Erik_Verduzco_
Pearl Harbor survivor struggles in her senior years
Winifred Kamen, 77, survived the attack on Pearl Harbor as an infant, works a 100 percent commission telemarketing job to make ends meet. (K.M. Cannon Las Vegas Review-Journal)
Las Vegas Metropolitan Briefing 18th street gang
Las Vegas Metropolitan briefs the media on the recent arrests made regarding the 18th street gang.
Man shot in Las Vegas traffic stop had knife, police say
Police said the man fatally shot by an officer during a traffic stop in downtown Las Vegas had a “homemade knife.” Demontry Floytra Boyd, 43, died Saturday at University Medical Center from multiple gunshot wounds after officer Paul Bruning, 48, shot him during a traffic stop. Bruning pulled Boyd over on suspicion of driving recklessly at 7:41 a.m. near Sunrise Avenue and 18th Street.
Catahoula dogs rescued from home in Moapa Valley
Catahoula dogs were brought to The Animal Foundation after being rescued from home in Moapa Valley.
Intuitive Forager Kerry Clasby talks about losses in California wildfire
Intuitive Forager Kerry Clasby talks about losses she suffered in California's Woolsey Fire in Malibu in November. (Al Mancini/Las Vegas Review-Journal)
Benefit dinner for Kerry Clasby, the Intuitive Forager
Sonia El-Nawal of Rooster Boy Cafe in Las Vegas talks about having a benefit for Kerry Clasby, known as the Intuitive Forager, who suffered losses on her farm in California’s Woolsey Fire in Malibu. (Al Mancini/Las Vegas Review-Journal)
Former President George H.W. Bush dies at 94
Former President George H.W. Bush has died at the age of 94. He died Friday night in Houston, about eight months after the death of his wife, Barbara.
Las Vegans Celebrate Big Snowfall
Las Vegans celebrate big snowfall at Lee Canyon.
Exploring old mines for denim jeans and other vintage items
Caden Gould of Genoa, Nev. talks about his experiences looking for vintage denim jeans and other items in old mines and other places areas across Nevada and the west.
Officers share photo of dead gunman after Las Vegas shooting
A little over an hour after SWAT officers entered Stephen Paddock's suite at Mandalay Bay, Las Vegas police officers far from the scene were already sharing cell phone photos of the dead Oct. 1 gunman.
TOP NEWS
News Headlines
Add Event
Home Front Page Footer Listing
Circular
You May Like

You May Like