If an asteroid is found to be on a collision course with Earth, it could be deflected, a scientist from the European Space Agency (ESA) said at the Johannesburg Planetarium on Saturday.
An asteroid called Apophis, which means ”the destroyer”, was detected in 2004 and was initially projected to collide with the Earth in 2029, with potentially catastrophic results. This is no longer a certainty, though, said the ESA’s Dr Sima Adhya.
The asteroid, currently moving at a speed of 30km a second, would have to pass through a 400m-wide region in space, called a gravitational keyhole, in 2029. If this happened, it would collide with Earth seven years later, in 2036, said Adhya.
Meanwhile, in the past year, Adhya has been working on the first phase of an asteroid-deflection project called Don Quixote. It involves two spacecrafts being sent into space to deflect another 300m-wide asteroid.
The first spacecraft will launch in 2011 and orbit the asteroid to take accurate measurements of the object and its exact positioning in space.
The second spacecraft, about the size of a fridge, will be launched afterwards and collide with the asteroid at a relative velocity of 10km per second, deflecting its course. ”It will act as a ballistic missile,” she said.
The first spacecraft will remain in orbit to measure the deflection. According to Adhya, a mere 100m deflection is sufficient to change an asteroid’s course.
Adults and children were also treated to a mini-tour of the universe. ”The next 20 years in space are going to be a very exciting time,” said Adhya.
Starting with the Big Bang explosion that created the universe 14-billion years ago, Adhya described how humans are made up of cosmic dust; how the Earth is being orbited by more than 10 000 stars; that 30 years after its launch, the Voyager spacecraft is ”just reaching the edge of the solar system”; and that plans are afoot for a human-inhabited village on the moon by 2025.
After the presentation, Adhya was flanked by a number of children asking how big the universe was, how a planet was made and whether she thought unidentified flying objects and aliens were real — and she had an answer for all of them.
Adhya is touring the country as part a two-week Sasol SciFest road show that aims to bring the flavour of the festival, which takes place in Grahamstown in March, to the rest of the country. — Sapa