4
votes
2answers
116 views

Why don't planets and asteroids have (cometary) tails?

Comets have tails. We all know that, and a lucky few have seen the better known. So why don't the planets (e.g. Earth, Mars) have tails? Why don't asteroids don't have tails?
-2
votes
1answer
176 views

Is it possible the Nebular Hypothesis and Planetesimal Theory are not correct? [closed]

For almost 3 centuries now the Nebular Hypothesis and Planetesimal Theory have become the preeminent explanations for how the Solar System and Planets evolved. Yet there is still no explanation for ...