Travelers In The Night

The large dangerous asteroids that we don't know about are what keep asteroid hunters going to the telescope.

As the Earth orbits the Sun at 18.5 mi/s it sweeps up about 100 tons of micrometeorites and space dust every day of which some 14 tons eventually makes it to the ground. You can even find some of these particles of space dust by using a magnet on material in the rain gutters attached to your roof.

Tonight, even though the chances are extremely slim, an asteroid hunter could find a sizable asteroid on a collision course with planet Earth. If we have decades warning, the potential impactor's arrival time could be changed by impacting the dangerous object with a high velocity mass or if we have less time we will need to nuke it which will either blow it to bits or give it a rocket like push.

When accurately recorded historical observations do not agree with what we what we see today it is often very rewarding to find out why. In modern telescopes we see Theta Eridani to a be pair separated by about 425 times our distance from the Sun orbiting a common center of gravity. Detailed observations of the spectrum of one of these show it to be itself a pair of stars orbiting each other every 4.1 days. One of this very close pair, as it is aging, dumps matter onto its companion causing it to brightened significantly. In the past this mass transfer rate was much higher than it is today and the naked eye brightness of Theta Eridani is fainter to us than it was long ago.

In the future one can envision a space mining family boarding a descendent of the SpaceX Falcon Heavy Launch Vehicle for a trip into low Earth orbit. A few hundred miles above the Earth's surface they would rendezvous with their asteroid mining spacecraft which will be their home for the next five years or so.