小编摘要：Falling star很唯美，但这回坠落的不是star而是satellite，6吨重，巴士大小，坠落地球，会不会有点恐怖。这颗卫星预计于今天下午坠地，你能否躲避一颗falling satellite呢。
导读：正向地球袭来的这颗美国失控卫星，6吨重，巴士大小，预计于9月23日下午坠地。据悉，卫星将分解成26个小碎片坠落，最重的一块将达158kg，相当于一名体格庞大的人类。碎片包括三块电池、四枚钢圈和四只油箱，坠落的速度会因着地点是陆地或海洋而不同。不过专家说，人们不必太担心是否会被卫星砸中，因为这个概率只有三千二百分之一。至今有记载的人类被卫星砸中事件，只有1997年美国俄克拉荷马州的一名叫Lottie Williams的女子在家附近散步时，被火箭Delta II的碎片击中肩膀，但其并未受伤。
The UARS was launched in 1991 by the Space Shuttle Discovery
A six-tonne satellite is expected to crash land in the next 24 hours, scattering debris over an area of the planet's surface up to 500km (310 miles) wide.
Nasa, which owns the Upper Atmosphere Research Satellite (UARS), estimates it will break into about 26 parts, the heaviest weighing about 158kg, which is equivalent to a very large person.
The debris will include three batteries, four wheel rims and four fuel tanks, and their speed when they hit the ground or the ocean will vary.
The rims, for example, could reach speeds of 107 metres per second (240mph), which is faster than one of France's high-speed TGV trains and 10 times quicker than Usain Bolt.
So is it possible for humans to ensure they don't get hit?
"Potentially, you could get out of the way," says Richard Crowther of the UK Space Agency, which is a member of a global network of agencies that monitors space debris.
"But if you're going to spend all the time looking up then you're at greater risk of an accident bumping into something than something coming down on you."
Equally, if you want to avoid the risk of being hit completely, he says, then you need to go beyond 57 degrees latitude north (Scotland or Quebec) or south (further south than the southern tip of Argentina).
"But travelling there will involve a greater risk than the risk of being hit by this."
Even if it is coming to your neighbourhood, you won't get much notice.
Nasa is tracking the object in orbit and said on Thursday that it was expected to re-enter the atmosphere on Friday afternoon on the US east coast (evening in the UK, which is five hours ahead).
But Nasa doesn't know where it will land, partly due to continuous changes in the atmosphere caused by the Sun. And the uncertainty surrounding the satellite's final destination will continue until its final minutes.
In 1979, when the Skylab space station fell to Earth, it missed the expected landing in South Africa and crashed in Western Australia.
The US Military and Iridium Satellite LLC both confirmed that, according to US East Coast time, at 11:55 a.m. on 10th, a commercial Iridium communications satellite collided with a