What Is The Hottest Planet In The Solar System?

The solar system is a big place. And with such a vast amount of space and celestial bodies, comes a whole range of incredible environments that would be unthinkable on Earth.

Whether it is the never-ending storm that clouds Jupiter. The frozen, dusty wastes of Mars. The rings of Saturn, or all the other incredible moons and planets that dot our little corner of the cosmos.

What Is The Hottest Planet In The Solar System?

With such a system of extremes, questions naturally start to arise about these extremes.

Take Venus, for example. Named after the Roman god of love and beauty, this is one of the most extreme places in our solar system.

It’s insanely hot, and it has one of the most crushing atmospheres out there in the cosmos. This is a planet that pretty neatly fits into a classic image of Hell.

But why exactly is it like this? What makes this planet tick? And why is it that a planet, so like our own in so many ways, and not even the closest to the sun, is still so incredibly hostile?

Well, that’s what this article is here to help answer! We’re going to go into a little detail as to what makes Earth’s closest cosmic neighbor the way it is, what makes it the hottest planet in the solar system, and why it is that other planets that might seem to be contenders for the hottest spot in the solar system simply aren’t.

So let’s dive right in!

Venus: A Hot Spot Amongst The Stars

First things first, we need to talk about Venus. As we mentioned at the beginning, Venus is the closest planet to us in terms of distance.

It orbits the Sun once every 224.7 days, compared to the Earth’s comparatively sluggish time that takes 365.

This means that when it comes to planetary distances from the Sun, Venus ranks as the second-closest planet, behind Mercury. But while Mercury is closer than Earth, it isn’t much hotter than Earth.

So how can Venus be so much hotter than its neighboring planet?

It turns out that Venus’ atmosphere is made up of 96% carbon dioxide, 3% nitrogen, 2% argon, 0.9% oxygen, and traces of other gases.

These make up an extremely dense atmosphere, which is one of the reasons that makes Venus so distinct from so many other planets, especially amongst the rocky planets that inhabit the inner part of the solar system.

Because of this, the surface temperature of Venus is around 864 degrees Fahrenheit (462 degrees Celsius).

Compare this to the surface temperature of the Earth, which hovers around 57 degrees Fahrenheit (14 degrees Celsius). In terms of pure heat, there is no comparison between these two planets.

The surface of Venus is constantly being baked by the intense heat coming from the sun.

As well as this, the thick atmosphere also plays a huge role, acting as a greenhouse gas that traps the heat inside, making the surface temperature rise higher and higher.

Why Does Venus Have Such An Intense Atmosphere?


Now, you may have noticed something else about Venus. If you look closely, you’ll see that it appears to be surrounded by a ring of clouds.

Those clouds, as well as the atmosphere that Venus has, are the reason behind its hellish landscape. Those aren’t normal clouds that we see here on Earth, those are clouds composed purely of sulfuric acid!

It has been speculated by scientists that, hundreds of millions, maybe even billions, of years ago, Venus very much resembled Earth in many ways. They are roughly the same size and have a similar geological composition and mass.

So what made Venus the way it is today?

Well, part of that is likely due to the loss of Venus’ water content over time. When Venus was originally formed, it is believed that it had a lot more water on its surface.

However, within roughly the last billion years, something caused the atmosphere of Venus to start building up higher levels of carbon dioxide, which was causing the amount of heat radiation that it could release to get smaller, causing the surface temperature to rise uncontrollably.

This caused most of the water to eventually evaporate, which only exacerbated the heating effect on the planet.

The result was a runaway greenhouse effect, where the entire planet began heating up rapidly, with temperatures on the molten planet today reaching around 932 degrees Fahrenheit (500 degrees Celsius) on average.

Many have pointed to the fate of Venus as a potential worst-case scenario for Earth’s own greenhouse effect as a result of modern global warming, but thankfully, our planet’s warming hasn’t yet reached the point where Venus has.

Life On Venus?

So, with such a drastic loss of control over its surface, you would think that Venus is simply a toxic volcanic wasteland, with no chance of life existing anywhere on the planet at this point, after hundreds of millions of years of global warming and crushing pressure.

But that might not be the case.

Whilst the surface of Venus is an unlivable landscape, the higher from the surface of the planet you travel, the atmospheric pressure, heat, and toxicity drop quite quickly.

In fact, it has been speculated and theorized that, approximately 30 miles up in Venus’ atmosphere, because the temperature sits around 86 to 176 degrees Fahrenheit, or 30 to 80 degrees Celsius, there is the potential for some type of life form to exist, even if it is just at a microbial level.

Even here, however, the acidity of the atmosphere would make life difficult for virtually any kind of life form, and without physical proof, we can never know for sure whether anything lives out there.

That said, there is one thing that we do know: Venus is far too hot for human beings.

The conditions are simply too extreme for humans currently to visit it, with its myriad of killer conditions on Earth-based biology. Any future exploration will have to be done by machine drones and robot explorers for us.

What About Mercury?


With all this talk of Venus being the hottest, many people might be wondering why Mercury hasn’t been mentioned as a potential candidate for the title of the hottest planet in the solar system.

Certainly, this little rocky planet has a strong case for being one of the hottest planets in our celestial neighborhood.

Being the closest planet to the sun, Mercury’s surface can get incredibly hot, with temperatures reaching as high as 800 degrees Fahrenheit (427 degrees Celsius), which puts it within a hair’s length of the hottest planet in our solar system, right behind Venus.

The reason for this, however, is actually the total opposite of Venus. Whereas the latter’s heat is due to the intense atmosphere, Mercury’s is due to its lack of it.

With no atmosphere to protect its surface from the much closer sun’s rays and heat, the surface of Mercury has no natural defense mechanism to stop the sun’s heat from bathing the planet’s surface in temperature hot enough to melt tin!

However, this lack of atmosphere also means that any heat that Mercury receives has no way of being retained.

Nights on Mercury can get as cold as -280 degrees Fahrenheit (-173 degrees Celsius) at night, making it one of the coldest places in the solar system, outside the outer reaches of our planetary neighbor Pluto.

It also gives Mercury the title of the greatest range of surface temperatures in the solar system.


So, who is the king of the solar system when it comes to the hottest planet? Well, it seems that it’s going to be a tie between Venus and Mercury, but in the end, Venus takes the top hotspot over Mercury.

Why? Because, unlike Mercury, Venus has an atmosphere that stops heat from escaping.

This atmosphere traps heat next to the surface, giving it the power to reach extremely hot temperatures. If you wanted to go looking for life elsewhere in the solar system, then we’d steer clear of Venus!

Gordon Watts