Are we losing the Sahara to space? No, is the simple answer to that. The Earth has a trail of dust behind it but the dust is interstellar dust which is already present in the solar system. This interplanetary dust comes from the fragments of comets and asteroids that have collided. As the Earth travels through this dust the dust is disturbed and leaves what looks like a trail are behind it.
There is another way of looking at the formation of the dust tail. The Earth leaves behind it an area of almost suction like quality that sucks the dust in from the edges giving the appearance of a dust tail. The dust tail is pulled along by gravity and leaves a trail around the sun.
The Spitzer telescope found the dust tail a few months ago as it went straight through it. This has allowed the dust tail to be mapped and shows how the tail can give an indication of a planet. Distant exoplanets around stars many light years from our own can be indicated by strange features drawn in the dust tail by these planets. These features can be bumps, warps, rings and offsets.
The dust has already been followed in other planetary systems other than our own. About 20 dust discs have been seen and have led to a few planets already being found. One of these was found around a star called Formalhaut.
These dust tails will help the future James Webb space telescope to hunt for extra solar planets and hopefully find them quicker.
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