In space terms, 2013 is going to be a vintage year. Asteroids are flinging their way into our orbit, storm “detectives” are probing Earth’s magnetic field to uncover the mysteries of energy, and the Near Earth Object (NEO) folk at the Jet Propulsion Laboratory in California are thinking up ingenious ways to stop any large chunks of rock from coming too close to our doorstep.
Asteroids are first up – like this Friday night, just after dinner. That’s when a dark monster of rock, as big as a four-bedroomed house – as big as President Jacob Zuma’s dwelling – is destined to enter Earth’s orbit, lumbering its way towards the planet – a close encounter in space terms.
The asteroid will pass by satellites in geostationary orbit about 35 800km above the equator, reportedly putting a communications satellite at risk of being hit – and us Earthlings in the dark.
“It’s not likely, but we can’t rule it out,” says Paul Chodas, a planetary astronomer at Nasa’s Jet Propulsion. “The orbit for 2012 DA14 is currently very Earthlike, which means it will be very close to Earth on a regular basis.”
But don’t worry. It won’t hit us, well not this year anyway, assures fellow scientist Donald Yeomans, manager of the Nasa’s Near Earth Object Programme Office.
“A collision between Earth and asteroid 2012 DA14 (surely they could have thought of a better name – what about the Incredible Chunk?) is approximately one chance in 83 000,” he says.
Yeomans believes, however, that additional observations “especially this year” will allow a dramatic reduction in the orbit uncertainties.
“We’ll understand their behaviour better – that’s what we hope.”
This potentially dangerous space missile presence was discovered last year by an alert team of Spanish scientists who seemed to come upon it just by chance, while they were searching the heavens for something completely different.
“That is not as extraordinary as it sounds,” says University of KwaZulu-Natal space physicist, Andrew Collier. “Asteroids, by their rock or iron nature, emit no light, so they are not easily identifiable.”
The good news is that they move quite slowly, “so we would have time to make plans if a large one was coming our way. Although quite what we could do about it is another issue”.
Collier says he will be monitoring the progress of the asteroid with huge interest. “There are several million asteroids in the asteroid belt which lies between the planets of Mars and Jupiter.
“What is fascinating and unpredictable are the gravitational forces, the energy, which can randomly fling them off in different directions and on to different orbits. If they head in the sun’s direction, then they are coming closer to us.”
The asteroid, Nasa says, will be within range for small telescopes and solidly mounted binoculars, used by experienced observers who have access to appropriate stars charts.
The exact shape and size of the monster will be only known on Friday when it becomes more visible.
2012 DA14 will travel rapidly from the southern evening sky into the northern morning sky with its closest Earth approach occurring at about 8.30pm South African time, when it will achieve a magnitude of less than seven, which is somewhat fainter than naked-eye visibility.
About four minutes after its Earth close-approach, there is a good chance it will pass into the Earth’s shadow for about 18 minutes or so before reappearing from the eclipse.
When travelling rapidly into the northern morning sky, it will quickly fade in brightness.
Believe it or not, a surprise near- miss by an asteroid is not especially unusual. In June 2011, an asteroid estimated at about 9m in size passed by Earth and missed a direct hit by only 12 070km.
An even closer encounter occurred earlier in 2011 when another small asteroid missed Earth by just 5 470km.
Among the solutions being considered for near “invaders” by the NEO laboratory are deflecting the asteroid trajectory by nudging it with robot space vehicles, or destroying the asteroid with a nuclear-armed rocket.
One of the most intriguing ideas is to deflect an approaching asteroid with paintballs.
While this sounds pretty far out there at first, the approach formulated by an MIT graduate student recently won the top spot of a competition sponsored by the UN Space Generation Advisory Council
And that, for now, is the asteroid news. Even more interesting is that three solar storm satellites (known as Swarm because they all hang out together) have been launched into space to probe the Earth’s mysterious magnetic field, a radioactive cushion that protects Earthlings from solar storms.
Collier says: “This is a major interest for our research scientists in KZN, who will be tracking the data very closely.
“Understanding how the waves of energy and the particles behave at that level has a direct bearing on the weather conditions, ocean currents and even climate change on Earth.
“We know things are changing pretty fast, that the magnetic strength is waning, but what that change will mean, we don’t yet know.”
What we do know is that Collier’s research students stationed in the Arctic are developing a series of observation balloons that will provide information on the magnetic strength closer to Earth.
“Once we have these two co-ordinates in place, in space and on Earth, who knows what we will learn?”
Scientists developing the storm satellites say that the magnetic field is shifting at a faster rate than at any time in human history – more than 60km a year – which may mean the beginning of a complete pole reversal
The changes are already beginning to cause problems for aviation, navigation and migratory animals that use the Earth’s magnetic field to orient themselves.
Some airports have had to change the names of their runways to better correspond to their current direction relative to magnetic north.
Could we already be experiencing the effect of solar storms?
Could the compass point south?
Scientists say it has probably happened before.