Astronomers did not discount the possibility that a new comet, C/2013 A1, discovered early this year by Robert McNaught at the Siding Spring Observatory in New South Wales, may hit planet Mars in October 2014.
While their calculation said the closest approach of the newly discovered comet would be a distance of 109,200 kilometres from the Red Planet, astronomer Ian O'Neill from Discovery Space said it is too early to foretell the course of the comet.
He said the comet has been observed so far for only 74 days, so it is hard for astronomers to make a precise forecast of its movements within the next 20 months.
Mr O'Neill estimated the comet would have a breakneck speed of 35 miles per second. Leonid Elenin, a comet specialist, said that as a hyperbolic comet, C/2013 A1 moves in a retrograde orbit with a very high velocity.
"With the current estimate of the absolute magnitude of the nucleus M2 = 10.3, which might indicate the diameter up to 50 kilometres (30 miles), the energy of impact might reach the equivalent of staggering 2x10^10 megatons!" Mr Elenin was quoted by NBC News.
The discovery of the comet by Mr McNaught led astronomers at the Catalina Sky Survey in Arizona to go over their observation and found pre-recovery images of the comet as far back as Dec 8, 2012.
Based on their observations, they forecast the orbital trajectory of the comet to go through Mars's orbit on Oct 14, 2014.
Amateur astronomers are bracing for a spectacular galactic display whether the comet hits or misses Mars. Some want to test if the orbit could be captured as high-resolution images when the flyby happens.
In 1994, the comet Shoemaker-Levy 9, which was 15 kilometres in diameter, hit planet Jupiter and the space spectacle was seem from Earth orbit by the Hubble Space Telescope.
News of the possible comet hit on Mars comes at a time that there is much interest on missions to the Red Planet.
On Thursday, Dennis Tito, the first space tourist who is organising a private mission to Mars by 2018, said he plans to include an elderly male and female couple in the trip expected to last 501 days. The lucky pair would have their expenses covered by Mr Tito.
He explained the male-female elderly couple spec to being representatives of both genders should they encounter other inhabitants on Mars, preferably being married to a proof of their ability to withstand each other's company for a prolonged period, and the age factor to the radiation exposure risk which could affect the reproductive ability of younger couples still in their childbearing years.
"When you're out that far and the Earth is a tiny, blue pinpoint, you're going to need someone you can hug . . . What better solution to the psychological problems you're going to encounter with that isolation?" The Register quoted Mr Tito.
"Clearly there are risks associated with the mission, as is true of every space exploration mission. But these are exactly the kinds of risks that America should be willing to take in order to advance our knowledge, experience and position as a world leader. We believe the risks and challenges we have identified are well within the scope of our collective experience and can be overcome to achieve a safe and successful mission," he added.