Because they all condensed out of the same cloud of spinning dust and gas.
Jupiter Neptune
The planet that most extrasolar planets resembles Jupiter.
Jupiter(apex)
Most of the confirmed Exoplanets are larger gaseous planets with large masses. These are easier to detect and confirm due to their size. They most resemble Jupiter, although many are thought to be much larger than our largest planet.
An explosion disturbs the gas and dust in the nebula.
They were formed in supernovae.
That is called a "black hole".
The Oort cloud
White dwarf
Light from the stars they orbit makes it difficult to see them.
Stars like our sun and hydrogen bombs produce energy through nuclear fusion.
star of one stellar mass, red giant, planetary nebula, white dwarf
They don't understand how redshift affects stars.
Pressure and gravity