A large asteroid, which was expected to pass extremely close to Earth, may now hit the blue planet in 2068 due to a phenomenon called Yarkovsky effect, which has eventually accelerated its flow and changed its path. However, astronomers closely studying the asteroid believe that chances of any impact are very low, but still a possibility. They "will know well before 2068 if there is any chance of an impact".
Discovered in 2004, asteroid Apophis is equal to the size of three football field -- around 300 meters. Its orbit has been disturbed by the heat from the Sun, reports said.
According to a report in Space.com. the sun can heat an asteroid in a non-uniform way, causing the space rock to radiate heat energy asymmetrically. This can cause a thrust or a tiny push in a certain direction, sometimes changing the path of the asteroid. This effect is called the Yarkovsky acceleration.
"All asteroids need to reradiate as heat the energy they absorb from sunlight in order to maintain thermal equilibrium, a process that slightly changes the orbit of the asteroid," a press release said.
Before the discovery of Yarkovsky effect, the possibilty of the collision was impossible. "The detection of this effect acting on Apophis means that the 2068 impact scenario is still a possibility," it read.
As per the new calculations by astronomers at the University of Hawaii at Manoa, asteroid Apophis, which will also be extremely close to Earth on April 13, 2029, is deviating from its actual orbit and may crash into Earth in 2028.
Lead author David Tholen said in a press release on October 26, "We have known for some time that an impact with Earth is not possible during the 2029 close approach."
"The new observations we obtained with the Subaru telescope earlier this year were good enough to reveal the Yarkovsky acceleration of Apophis, and they show that the asteroid is drifting away from a purely gravitational orbit by about 170 meters per year, which is enough to keep the 2068 impact scenario in play," he said.
"Basically, the heat that an asteroid radiates gives it a very tiny push... The warmer hemisphere [of the asteroid] would be pushing slightly more than the cooler hemisphere, and that causes the asteroid to drift away from what a purely gravitational orbit would predict," David Tholen was quoted as saying during a press conference.
He said that some astronomers found asteroid Apophis quite troublesome with "numerous impact scenarios" predicted and then largely ruled out since it was first discovered in 2004.
APOPHIS'S FLYBY ON FRIDAY THE 13TH
Asteroid Apophis, named after the Greek God of Chaos, will be visible to the unaided eye as it is expected to harmlessly zip past Earth on April 13, 2029, which fall on Friday, the release said.
"The Apophis close approach in 2029 will be an incredible opportunity for science," said a scientist at Nasa's Jet Propulsion Laboratory in Pasadena, California.
During its 2029 flyby, Apophis will first become visible to the naked eye in the night sky over the southern hemisphere and will look like a speck of light moving from east to west over Australia. It will get brighter and faster as it will zoon past Earth.
According to Nasa, during its 2029 flyby, "asteroid Apophis will first become visible to the naked eye in the night sky over the southern hemisphere". It will look like "a speck of light moving from east to west over Australia".
Apophis will then cross above the Indian Ocean, and continuing west, it will cross the equator over Africa, Nasa said.
Apophis is a 1,120-foot-wide (340-meter-wide) asteroid. That’s about the size of three-and-a-half football fields, Nasa said.