Is our solar system weird? Most others are different (Introduction)

by David Turell , Wednesday, July 05, 2017, 00:09 (2698 days ago) @ David Turell

The Kepler studies so far find other solar systems are not like ours:

https://www.newscientist.com/article/mg23531324-100-planets-in-other-star-systems-fit-a...

"EXOPLANETARY systems are like peas in a pod, whatever type of star the planets orbit. This challenges our ideas about how such systems form.

"A team led by Lauren Weiss at the University of Montreal in Canada has looked at 909 planets discovered by the Kepler space telescope in 355 systems. All planets in a given system seem to be close in size and similarly spaced in their orbits when compared with planets in other systems. “We see this pattern happening again and again,” says Weiss – regardless of what kind of star these planets are orbiting.

"That’s not what we’d expect, given how we think star systems are born: that stars form from a cloud of gas and dust, pulling it into a thick disc as they rotate. Denser clusters of gas and dust within the disc condense into planets, suggesting there should be a link between planets and their star.

"The team thinks something other than stellar mass must influence how protoplanetary discs give rise to planets, such as the total mass of the disc, the solid mass within the disc or what happens to the disc after a planet’s initial formation.

“'There’s probably something related to the physics of the disc that the planets are forming in that is determining how big the planets grow and how far apart from each other they end up,” says Weiss. “But this idea has yet to be tested.”

"It’s also possible that these patterns are just a fluke created by our limited data. Kepler can only find planets with short orbital periods – those that crossed in front of their star during the four years of the spacecraft’s mission. That’s like only looking at Mercury, Venus, Earth and Mars in our own system.

"So can we really build theories on Kepler’s limited observations? “That’s the question that keeps me and many other people up at night!” says Weiss."

Comment: It is possible our system is unique in order to have life on Earth, but the thought that the Keppler system cannot see systems like ours must be considered.