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The ices that formed the Jovian planets were more abundant than the metals and silicates that formed the terrestrial planets, allowing the giant planets to grow massive enough to capture hydrogen and helium, the lightest and most abundant elements. [11] Planetesimals beyond the frost line accumulated up to 4 M E within about 3 million years. [38]
The universe is supercooled from about 10 27 down to 10 22 kelvin. [3] c. 10 −32 seconds: Cosmic inflation ends. The familiar elementary particles now form as a soup of hot ionized gas called quark–gluon plasma; hypothetical components of cold dark matter (such as axions) would also have formed at this time.
These satellites were the first celestial objects that were confirmed to orbit an object other than the Sun or Earth. Galileo saw Io and Europa as a single point of light on 7 January 1610; they were seen as separate bodies the following night. [11] Callisto: Jupiter IV o: 8 January 1610 p: 13 March 1610 Io: Jupiter I Europa: Jupiter II 1650s
However, Pierre-Simon Laplace refuted this idea in 1796, stating that any planets formed in such a way would eventually crash into the Sun. Laplace felt that the near-circular orbits of the planets were a necessary consequence of their formation. [8] Today, comets are known to be far too small to have created the Solar System in this way. [8]
The Karin family, formed 5.8 million years ago, and the Koronis family, formed 7.6 million years ago, account for a class of meteorites called H chondrites that represent 33% of known Earth ...
During this epoch, the temperature and average energies within the universe were so high that subatomic particles could not form. The four fundamental forces that shape the universe—gravitation, electromagnetism, the weak nuclear force, and the strong nuclear force—comprised a single fundamental force. Little is understood about physics in ...
Pluto likely acquired large moon Charon in a “kiss and capture” collision billions of years ago. It may have created a subsurface ocean on the icy dwarf planet.
Counting them among the planets became increasingly cumbersome. Eventually, they were dropped from the planet list (as first suggested by Alexander von Humboldt in the early 1850s) and Herschel's coinage, "asteroids", gradually came into common use. [139] Since then, the region they occupy between Mars and Jupiter is known as the asteroid belt.