An often-asked question, repeated in Letters last week, is: 'Why don't we get rid of our waste products, including nuclear, into the sun?' The Sun's gravitational pull on the earth is balanced by centrifugal force as the earth circles in its orbit at a distance of about 90M miles. That is, the Earth travels about 285M miles in a year or 32,500 miles per hour along its orbit. Before any such waste matter in an earth orbit can 'fall' into the Sun, we have to kill the centrifugal force by slowing the orbital speed of the waste to zero.
That is the same thing as launching the waste from earth at a speed of 32,500mph, much greater than the effort of sending it to the Moon.
Anything less and the expelled waste will go into some intermediate solar orbit and add to the pollution of space, which is already a feature of low satellite orbits around the earth.
Provided such waste is launched from near the Equator, we do 'save' about 1,200mph by using the rotational speed of the earth about its own axis, so perhaps we should look to tropical countries for a lead here.
Chris May (M), Woodbine Farm, High Street, Chew Magna, Bristol BS40 8PW