According to current scientific evidence, all planets in our solar system were created around the same time. The nebular hypothesis (sometimes referred to as the nebular theory depending on which scientist you ask, and how they view the validity of the mountain of supporting evidence) outlines the creation of all planets in a solar system takes place at roughly the same time; however it's been noted that the planets behind the 'snow line' (the threshold between rocky planetesimals and debris and where solid ice can form) form much later than the planets in front of the snow line.
In our solar system, it would appear that the asteroid belt between Jupiter and Mars was approximately where the snow line formed in our solar system, meaning the inner planets formed slightly earlier than the outer planets.
Using archeological data collected from our own planet, we've estimated the creation of Earth to be anywhere between 4.5 - 5 billion years of age.
Because of Uranus' and Neptune's common lack of mass compared to other gas giants, it's believed that their formation took place later than that of Saturn's and Jupiter's, at a point in which there was little matter left for accretion discs to form around the two planets, making them rather failed gas giants. This means that the planets are likely younger than Earth, yet their exact age is clearly unknown. They are estimated to be anywhere between 4 billion and 4.5 billion years old; however even that is a considerably rough estimate.
Unmanned probe missions to these planets and their rocky moons may reveal more interesting information, narrowing down the period of formation of these planets.
In our solar system, it would appear that the asteroid belt between Jupiter and Mars was approximately where the snow line formed in our solar system, meaning the inner planets formed slightly earlier than the outer planets.
Using archeological data collected from our own planet, we've estimated the creation of Earth to be anywhere between 4.5 - 5 billion years of age.
Because of Uranus' and Neptune's common lack of mass compared to other gas giants, it's believed that their formation took place later than that of Saturn's and Jupiter's, at a point in which there was little matter left for accretion discs to form around the two planets, making them rather failed gas giants. This means that the planets are likely younger than Earth, yet their exact age is clearly unknown. They are estimated to be anywhere between 4 billion and 4.5 billion years old; however even that is a considerably rough estimate.
Unmanned probe missions to these planets and their rocky moons may reveal more interesting information, narrowing down the period of formation of these planets.