Photo: Ann H

Who is the coolest planet?

Uranus holds the record for the coldest temperature ever measured in the Solar System: a very chilly -224℃.

hull.ac.uk - Curious Kids: what is the coldest planet in the Solar System?

Who were first to use the zodiac signs?

The Babylonians had already divided the zodiac into 12 equal signs by 1500 BC — boasting similar constellation names to the ones familiar today,...

Last updated Aug 9, 2018

What field produces the most millionaires?

finance The answer may surprise you: it's finance. In fact, according to Forbes magazine, finance is responsible for creating more millionaires...

Last updated Dec 13, 2018

Awaken your dormant DNA ability to attract wealth effortlessly

The simple yet scientifically proven Wealth DNA method laid out in the report allows you to effortlessly start attracting the wealth and abundance you deserve.

Learn More »

Promotion

The heat inside planets is left over from when they were formed. Planets are made when smaller chunks of rock smash together, building the full planet piece by piece over many millions of years. Every time these rocks smash together, the planet gains a little more heat. If you clap your hands together for a long time they will start to feel hot – the same thing happens with planets. Neptune wasn’t hit by a huge asteroid like Uranus was, so it has been able to hold on to more of its heat. You might also be surprised to learn that the closest planet to the Sun, Mercury, can also be extremely cold. While the side of Mercury facing the Sun is more than 400℃, the side facing away from the Sun is nearly -200℃. The reason for this is that Mercury does not have any atmosphere, unlike Earth. An atmosphere like ours acts like a blanket, holding heat in and spreading it all around. Because it does not have this blanket, the front side and the back side of Mercury can have very different temperatures.

Measuring temperatures in space

For some nearby planets like Mars, we can send probes to study the atmosphere directly from the planet’s surface. However, we haven’t been able to do this for distant planets such as Neptune and Uranus. Instead, we have to work out how cold they are by measuring their temperature from here on Earth. We do this by studying the light from the planet, which can tell us the types of atoms and molecules which make up the planet’s atmosphere. This information lets us know exactly what the temperature of the planet is: the atoms and molecules act as a kind of temperature “fingerprint” for the planet. While these planets in our Solar System are incredibly cold, there are even chillier places in the universe. The coldest of all is the Boomerang Nebula, a cloud of dust and gas 30 million billion miles away from us. There, the temperature reaches -272℃. Nothing in the Universe can be colder than -273℃, because at that temperature the tiny particles and atoms that everything is made of basically stop moving, and once that happens it’s impossible to go colder. This temperature is known as absolute zero. This means it is unlikely that we will ever find anywhere in the Universe colder than the Boomerang Nebula.

Article written by Professor Brad Gibson

Curious Kids is a series by The Conversation that gives children the chance to have their questions about the world answered by experts. If you have a question you’d like an expert to answer, send it to curiouskids@theconversation.com. We won’t be able to answer every question, but we’ll do our very best. This article is republished from The Conversation under a Creative Commons license. Read the original article.

What zodiac signs are rich?

Scorpio and Virgo lead the way When it comes to the most contributions made to the list, Scorpio and Virgo rank the highest. Billionaires with both...

Last updated May 18, 2020

Why do some people not work?

Structural barriers to employment include lack of jobs in a depressed area, a mismatch between employers' needs and workforce skills and...

Last updated Jul 24, 2021

Awaken your dormant DNA ability to attract wealth effortlessly

The simple yet scientifically proven Wealth DNA method laid out in the report allows you to effortlessly start attracting the wealth and abundance you deserve.

Learn More »

Promotion

Do we get money on 1k views?

On average, YouTube monetization for 1000 views (also known as CPM – Cost Per Mille) ranges from 0.5 to 6 USD based on the location of viewers and...

Last updated Jan 16, 2020

How do you attract God's favor?

One of the key things you greatly require to enjoy God's favour is, you must love God and do His will. In Genesis 39:4, the Bible says: “And Joseph...

Last updated Aug 23, 2021

Promotion

What does the Bible say about lavender?

It is believed that the lavender plant was taken from the Garden of Eden by Adam and Eve, however, it was not until the Virgin Mary laid the infant...

Last updated Aug 29, 2018

Awaken your dormant DNA ability to attract wealth effortlessly

The simple yet scientifically proven Wealth DNA method laid out in the report allows you to effortlessly start attracting the wealth and abundance you deserve.

Learn More »

Promotion

What does 888 stand for?

The number 888 is often symbolised within the international labour movement to symbolise the 8-hour day. Workers protested for 8 hours work, 8...

Last updated Sep 7, 2022