It’s a point that both science superfans and science sceptics miss: none of our observations are perfect

My friend Larry Lebofsky has been studying asteroids since we first met as students, more than 50 years ago. Now approaching 80 years old, he still spends a few days every month or so at our telescope in Arizona, searching the skies to “recover” asteroids that pass near the Earth.

Near-Earth Objects (Neos) are generally small rocks or piles of rock – a few metres to a few kilometres across – that pass within about 45 million kilometres to Earth’s orbit – close indeed by astronomical scales. These Neos are the ones that are easy to send a spacecraft to, whether to study it scientifically, exploit its mineral resources, or shove it out of the way if it gets too close to Earth. The latter are called potentially hazardous asteroids: those bigger than about 140 metres across whose orbits could bring them within about 7 million kilometres of Earth’s orbit. The European Space Agency counts 1,906 Neos in that category as of last week.

Get Instant Access

Continue Reading

Register for free to read this article in full

REGISTER

Subscribe for unlimited access

SUBSCRIBE NOW

From just £37.50 quarterly

  Print copy of The Tablet delivered directly to your door.
  Complete access to all Tablet website content including all premium content.
  Access to the weekly digital copy of The Tablet.
  Full access to The Tablet’s archive – over 180 years of back issues.

Already a subscriber? Login