Bill Napier, Chandra Wickramasinghe, and his daughter, Cardiff University student Janaki Wickramasinghe have proposed that thousands of undetected comets could be hiding in our Solar System.
The Solar System could be teeming with almost invisible comets, according to some astronomers' calculations. If they are right, such extra comets would significantly increase the risk of a catastrophic impact with Earth.
These objects have never been observed, but the astronomers argue that 'dark comets' provide a likely explanation for an astronomical puzzle: we can only see a tiny fraction of the comets that theory predicts.Astronomers think that many comets come from the Oort cloud, a field of billions of icy objects that lies up to 100,000 times farther away from the Sun than the Earth does and marks the outer boundary of our Solar System. The icy objects are sometimes driven towards the Sun by gravitational tides generated by the shifting masses of stars in our Galaxy. When this happens they become comets, orbiting the Sun every 20 to 200 years on paths that lie at an angle to the planets' orbits.
Given the size of the Oort cloud, astronomers have calculated that there should be about 3,000 comets in these orbits, 400 times more than are actually observed.
Looks like we'll be able to test the hypothesis shortly-
Earlier this month, NASA announced that it would launch an orbiting infrared telescope called the Wide-field Infrared Survey Explorer (WISE) in 2008, which will map much wider areas of the sky. Given enough time, it should be able to detect the dark comets, says Napier.Ugh. I hate that "given enough time" part. Yes, let's cross our fingers and hope that we get enough time. Wonderful.
NASA has been spending $3-4 million a year to find and characterize the estimated 1,100 large-sized NEOs, a goal it set in 1998 under pressure from Congress. This is is a pittance in relation to the overall trillion dollar NASA budget. We absolutely must divert funds from the current NASA budget towards expanded search and mitigation research.
Not much use in having a space station in orbit when there is no one left on the ground to visit it.
Maybe not in my lifetime, or in the next few generations lifetimes, but this is going to happen to the earth again one day. Not if, but when...