Neptune is one of the most fascinating planets in the Solar System. Not only is it the farthest planet from the Sun, but it also has the strongest winds in our planetary neighborhood and many other characteristics that make it captivating.
But there is a common question about Neptune that can be tricky to answer and can have multiple answers, and that is what is the temperature of Neptune? Is it hot or cold?
In this article, we are finally going to solve this puzzle and will tell you why it can be hard to answer with just a simple number.
What factors determine Neptune’s temperature?
There are multiple factors that affect a planet’s temperature. These include its distance to the Sun, composition, and the density and reflectiveness of the atmosphere.
Let’s take a look at these factors specifically for Neptune.
Distance from the Sun
Neptune is the eighth and farthest planet in the Solar System. It is located, on average, 4.5 billion kilometers (2.8 billion miles) away from the Sun. For comparison, it is approximately 30 times farther away from the Sun than Earth.
This means that Neptune receives significantly less sunlight than our planet, and usually that means it is going to be an extremely cold planet.
Composition
Neptune is an ice giant. This means it has a different composition than gas giants like Jupiter and Saturn, with a higher proportion of “ices” such as water, ammonia, and methane. Neptune has a thick, dynamic atmosphere surrounding a mantle of ice and a relatively small rocky core.
On one hand, this means that there is no solid surface that absorbs or retains heat from the Sun. It also means that a lot of the sunlight is reflected by Neptune’s blue methane clouds and doesn’t penetrate to the inner layers of the planet.
On the other hand, it also means that heat generated within the planet doesn’t escape easily. Similar to how Venus traps heat with its thick atmosphere, Neptune’s dense layers help contain internal heat.
So, that brings us back to our original question.
Is Neptune hot or cold?
The answer is both. And it depends on what part of Neptune you mean when you ask the question. The atmosphere and outer layers of Neptune are extremely cold. The average temperatures in this area reach −214°C (−353°F), making it one of the coldest places in the Solar System. However, the inner layers get hot rather quickly. It is estimated that the temperatures near Neptune’s core can reach 7,000°C (12,632°F).
Is Neptune hotter or colder than Earth?
The short answer is that Neptune is colder than Earth. The average temperature on Earth’s surface is 14°C (57°F) and the average temperature on Neptune’s outer layer is −214°C (−353°F). Remember Neptune doesn’t have a defined surface so that’s the closest we can make to a fair comparison.
However, that doesn’t tell the whole story.
The lowest temperature recorded on Earth’s surface is -89.2°C (-128.6°F), on Antarctica. It is also estimated that the temperature of Earth’s inner core is about 5,200°C (9,392°F).
So, in a way, you could say that Neptune is both colder and hotter than Earth depending on where you are measuring.
Summary
- Neptune is 30 times farther away from the Sun than Earth. This means it receives very little sunlight.
- Neptune’s atmosphere is extremely cold, with an average temperature of −214°C (−353°F). That is much colder than Earth.
- Neptune’s inner layers and core, however, are quite hot, reaching temperatures of 7,000°C (12,632°F).
