What are the similarities between Uranus and Neptune?

Uranus and Neptune are the two furthest planets from the Sun, and they’re often lumped in together with each other, much like Jupiter and Saturn are. And the main reasons for this is that there are a lot of similarities between the two planets, as they’re more alike than they are different.

This is probably best exemplified by their eventual re-classification from gas giants, like both Jupiter and Saturn which are both primarily made up of gas, to ice giants instead. Obviously, this is due to their composition – but what exactly are the main similarities between the seventh and eighth planet from the Sun?

What are the similarities between Uranus and Neptune?

One of the biggest similarities between the two planets is that they’re a very similar size to one another, with a similar mass too. They’re also both pretty well known for being the blue planets, though they do have a distinctive difference in blue-ness.

The size

Right, as mentioned probably the biggest similarity between these two planets is their size. It’s well known that the four Jovian planets – Jupiter, Saturn, Uranus and Neptune – are much bigger than the four terrestrial planets – Mercury, Venus, Earth and Mars.

However, out of the four planets that are further out from the Sun, Neptune is the smallest – it has a radius of 24,622 km. In comparison to this, Uranus has a radius of 25,362 km. So although it’s a little larger in size, there’s actually not much between the two here.

Now, despite Uranus being the bigger of the planets in size, it’s actually less massive than Neptune. Uranus has a mass of 8.681 × 10^25 kg, whereas Neptune has a mass of 1.024 × 10^26 kg. So, this is another similarity that the two have, though Neptune is the more massive of the two.

Finally, Uranus has the greater volume of the two, but not by much. Neptune has a volume of 6.3 x 1013 cubic kilometers, meaning that it could fit approximately 57 Earths inside, whilst Uranus has a volume of 6.83×1013 cubic kilometers, meaning you’d be able to fit 63 Earths in the planet. So, very similar in terms of size, mass and volume.


Another key reason why these two planets are often compared with one another is that they’re both made up of a lot of the same materials. This includes their atmosphere, which is primarily made from hydrogen and helium, with a little methane mixed in for good measure.

But underneath the atmosphere and gas is where these two are more likely than anything, as they’re both covered in water and ice. Obviously, this is down to their far distance from the Sun, but it’s still just one interesting fact about Uranus.

Internal temperature

One similarity between the two planets that is often missed is that they have a very similar internal temperature to each other. Although you may think this is to be expected because of their same composition, we need to remember just how much farther from the Sun Neptune is.

Uranus is approximately 20 AU away from the Sun, whilst Neptune is 30 AU from the Sun – so another ten AU for the Sun’s heat to travel. For context, they’re both reaaaally far from the Sun in comparison to Earth, which is only 1 AU.

Uranus at the core can heat up to around 5,000°c, whilst Neptune’s core can reach temperatures of 7,000°c – despite being much further out. This suggests that the planets probably have some internal heating system that gets them to these temperatures.


Although these two are both blue planets, they’re both pretty different colors to one another, so it’s not the greatest of similarities. You can check out this article if you want to know why Uranus and Neptune are both blue. However, though they are similar to one another, there are some differences between them too.

The number of moons that orbit each one is vastly different, with Uranus having almost double the amount of Neptune; Uranus also has more rings that its “twin brother” too, and this is just the start of the differences between them.

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