Cosmology: our unususal solar system (Introduction)

by David Turell , Saturday, April 04, 2015, 20:41 (3522 days ago) @ David Turell

Describes the theories of how our system formed and it doesn't fit the pattern seen around other stars:-https://medium.com/starts-with-a-bang/how-special-is-the-solar-system-bc6ecdb5a1ab-"Our solar system follows a clear pattern. Small, rocky planets close to the Sun, large gas planets farther out, and a belt of astroids between them. On a broad level that would seem to make sense. As the Sun formed, the intense energy of its newfound solar wind would tend to push lighter elements such as hydrogen and helium toward the outer solar system, leaving only rocky material behind. It's tempting then to imagine that most solar systems would follow a similar pattern of close rocky planets and more distant gas giants. But as we've discovered more exoplanetary systems, we find that isn't the case. In fact it increasingly looks like our solar system might be the exception rather than the norm.-"When we look at other star systems, we find that a gas planet far from its star is rather unusual. One way to categorize planets is by the energy they receive from their star. Hot planets, such as Mercury and Venus in our solar system, warm (possibly habitable) planets such as Earth and Mars, and cold planets such as Jupiter and beyond. The cut-offs for a particular system depend upon the energy produced by a particular star, but it gives a good idea of near, mid-range and distant planets. In our own solar system, all the gas planets are “cold” planets. But among all confirmed exoplanets, less than 20% of gas planets are cold. The most common type of gas planets are “hot jovians.” These are large, Jupiter-mass planets close to their star."