Kepler Discovers Solar System's Ancient 'Twin'

astroengine writes: Astronomers have found a star system that bears a striking resemblance to our inner solar system. It's a sun-like star that plays host to a system of five small exoplanets — from the size of Mercury to the size of Venus. But there's something very alien about this compact 'solar system'; it formed when the universe was only 20 percent the age it is now, making it the most ancient star system playing host to terrestrial sized worlds discovered to date.

Comments

Re:How are they rocky?

[Solandri]

Depends on the composition of your "rocky" planet. Fusion reagents are energy-positive up to iron. So basically, elements heavier than iron requires multiple supernovae to generate a substantial quantity. Elements lighter than iron can be released in just 1-2 supernovae.

The elements which make up most of the "rock" on our rocky planet are oxygen, silicon, calcium, iron, potassium, aluminum, and sodium. Of these, oxygen, silicon, and iron are a regular product of stellar fusion, and can be distributed from a single supernova.