The sun that heats our planet and brings life to everything on Earth is a big ball of gas. Those gases are mostly hydrogen and helium, but the sun also contains small amounts of several other elements, including oxygen, carbon, nitrogen, magnesium and iron.

At its core, the sun burns millions of tons of hydrogen every second in a process called “nuclear fusion.” Fusion turns hydrogen into helium and releases incredible amounts of energy in the process. It’s fusion that creates the heat and the rays of light that eventually reach Earth.

How hot does it get where you live during the summer? Temperatures over 100° F are common in many parts of the United States during the summer.

Just think about how hot it would be, though, if Earth were closer to the sun. At 93 million miles away, the Earth is just far enough away from the sun to allow us to live comfortably all year long.

What’s the hottest thing on Earth? Many people immediately think of lava, the hot, molten rock that occasionally flows from volcanoes.

Lava is indeed very hot, reaching temperatures of 2,200° F or more. But even lava can’t hold a candle to the sun!

At its surface (called the “photosphere”), the sun’s temperature is a whopping 10,000° F! That’s about five times hotter than the hottest lava on Earth. But the photosphere isn’t even the hottest part of the sun.

The sun’s temperature gets even hotter as you move away from the photosphere — either inward toward the core or outward toward the sun’s outermost atmospheric layer.

This outermost atmospheric layer is called the “corona.” The corona is the bright halo of light you can see during a total solar eclipse.

The farthest point of the corona from the sun can be as hot as 3,600,000° F. That’s right — 3.6 million degrees Fahrenheit. Incredibly, though, the corona isn’t the hottest part of the sun either.

To get to the hottest part of the sun, you have to travel all the way to its core. In the core, the process of nuclear fusion creates temperatures of approximately 27,000,000° F. A temperature of 27 million degrees Fahrenheit is more than 12,000 times hotter than the hottest lava on Earth!

If the core is the hottest part of the sun, what’s the coolest part? Occasionally, cool, dark areas of magnetic disturbances erupt on the photosphere.

Scientists call these areas “sunspots.” Sunspots tend to be cooler than surrounding areas and are usually “only” about 6,700° F.


92 Join the Discussion

1 Star2 Stars3 Stars4 Stars5 Stars  (61 votes, avg. 4.49 out of 5)
    • Wow, Kerrick Elementary 2nd/EBD classroom! Thank you for sharing all the great things you learned from today’s Wonder about the SUN! That video sure had our toes tapping here in Wonderopolis! We think music is a great way to help us all learn! :-)

    • You’re right about that, Me! We’re glad the sun gives us just the right amount of heat and light. Thank you for visiting Wonderopolis today! :-)

    • That’s REALLY toasty, isn’t it, Akash? It’s hard to even imagine what temperatures that intense might feel like! Thank you for commenting today and for being a GREAT Wonder Friend! :-)

  1. Hi, I’m James from Mrs. Caplin’s class. We were assigned to do homework about this wonder and I really liked learning about how the sun works and how hot it gets. What I really found interesting is that the gas in the sun is mostly helium and hydrogen. Anyway I have to get to football practice soon, so bye and I’ll comment more soon.

    • It’s so nice to meet you, James-MC! We’re glad you learned some new things by visiting today’s Wonder of the Day®! We look forward to reading and sharing more AWESOME comments from you and your classmates throughout the school year! :-)

  2. Hi, I am also from Mrs.Caplin”s class. I really liked the video, it was funny and I learned the sun is a medium sized star. I thought the sun was a large sized star.

    • We thought that was an interesting fact about the sun, too, Srikar-MC! Can you imagine how warm and bright it would be outside on our planet if the sun was a large-sized star instead of a medium-sized one? Thank you for leaving us this great comment! :-)

    • Hi, Wyatt MC! We’re so glad that you learned something new today! Thanks for visiting Wonderopolis and for commenting on this Wonder! :-)

  3. Hi, I’m Samia from Mrs. Caplin’s class. This is such a cool wonder, I had no idea that the sun was so hot. That’s amazing! I can’t wait to see tomorrow’s wonder!

    • We love your enthusiasm, Samia MC! Thank you for letting us know how much you enjoyed this Wonder of the Day® about the sun! :-)

  4. Hi, this is Leah from Mrs. Caplin’s class. I just finished my homework on how hot is the sun, and I was just wondering how do you come up with this stuff?
    Well, have to go.
    I’ll try to comment tomorrow.

    • That’s a GREAT question, Leah-MC!

      Everyone in Wonderopolis wonders all the time! We wonder about the world around us, about history, about things we eat…we just wonder, wonder, wonder! That’s how we come up with the ideas for each Wonder of the Day®. We also get AMAZING ideas from kids and adults, too! Did you know that YOU can submit an idea for a Wonder of the Day® anytime one pops into your head? Just click on the “nominate” link at the top of every page at and let us know what you’re WONDERing! :-)

  5. Hi! I’m Wyatt from Mrs. Caplin’s class. I learned so much about the sun! I did not know that the sun’s core is 27 million degrees. I also did not know that the sun was just a medium sized star and many Earths could fit inside it.

    • What an AWESOME comment, Wyatt MC! It’s pretty neat to think about all those little Earths fitting inside that HUGE sun, isn’t it? The video sure helped us understand that idea better (plus, we liked the song a lot, too)! :-)

  6. This is Alex from Mrs.Caplin’s class. I had a lot of fun learning about the sun. The thing that struck me the most was that the sun’s core is about 27,000,000 degrees F. That’s incredible!

    • Hi, Alex-MC! We think it’s a pretty incredible fact, too! We’re happy we get to study the sun from very far away where the temperature is comfortable! :-)

  7. Hi Wonderopolis! I thought the video was so cute. I wonder if the sun disappeared, would it get really cold and never stop snowing? Then humans would not be able to go outside and would become extinct.

    Maddy M.

    • Wow, Maddy! We’re so proud of you for wondering even more about the things you learned in this Wonder of the Day® about the sun! We need the sun for so many things (like warmth and light), so it’s hard to imagine life without it. Thank you for leaving such a great comment! :-)

  8. Wow, that’s a cool Wonder of the Day!!!! And by the way, the song is funny!! But I still like it! Thanks, Wonderopolis!

  9. Hi, I am Harshitha from Mrs. Caplin’s class. I really didn’t know that the sun has elements like nitrogen, carbon dioxide, magnesium, iron
    and oxygen. I also didn’t know that earth is ninety-three million miles away. Thanks for your information!

    • We’re so glad that you learned some new facts about the sun from visiting this Wonder of the Day®, Harshitha! We hope you are having a great school year so far in Mrs. Caplin’s class! She is an AWESOME teacher! :-)

  10. Hey this is Betty from Mrs.Caplin’s class. This wonder is really cool. I did NOT know that the sun is a middle sized star and it holds a million earths in it. I am wondering how many earths can the largest star have? I also learned a lot of new stuff but I can’t name them all because there are so many.

    • Hi, Betty! We’re so glad you left us a comment about this Wonder of the Day®! It’s awesome that you are doing some WONDERing of your own after learning about the sun! We’re not sure how many Earths could fit inside the largest star, but we bet it would be A LOT! Thanks for being a great Wonder Friend…keep WONDERing! :-)

    • Hello, Barbie! We’re sorry, but we don’t have any worksheets or puzzles for this Wonder of the Day® about the sun. Do you know what would be really AWESOME? If YOU made a puzzle or worksheet about the sun and shared it with US! Creating your own fun puzzle or worksheet will help you test what you learned about the sun.

      If you decide to make one, you can send it to us at: Wonderopolis HQ, 325 West Main Street, Suite 300, Louisville, KY 40202-4237. We’ll post your puzzle or worksheet to our Wonderopolis Facebook and Twitter pages so that ALL Wonder Friends can see it and try it out! :-)

    • We’re glad you learned some new facts about the sun by exploring this Wonder, Chris! Thanks for leaving us this comment to let us know you were here! :-)

  11. That is really hot! By the way, I knew that the suns surface is 9,900 degrees Fahrenheit not 10,000 degrees Fahrenheit. The sun is really big, too! It’s 100 times bigger than the earth! Now that’s hot and big! Jacob out.

    • Thanks for sharing what you know about the sun and adding something SUPER to this Wonder of the Day® with your comment, Jacob! You are a GREAT Wonder Friend! :-)

    • We’re so glad you think we’re doing a good job and that you like exploring Wonderopolis, Timothy! Thanks for letting us know you enjoyed the video for this Wonder of the Day®! :-)

  12. Hey wondeopolis I was reading part of the sentence about lava being the hottest thing on earth. I don’t know if this is something with my computer or the website, it doesn’t happen on any other site, so can you just tell me the whole sentence?

    • Hi there, Wonder Friend A! Thanks for joining us as we took a trip to outer space!! We’re sorry to learn that you couldn’t enjoy the entire Wonder, but we hope this helps!

      “To get to the hottest part of the sun, you have to travel all the way to its core. In the core, the process of nuclear fusion creates temperatures of approximately 27,000,000° F. A temperature of 27 million degrees Fahrenheit is more than 12,000 times hotter than the hottest lava on Earth!” :)

  13. OK…well…that By that I mean SUPER RIDICULOUSLY BOILING HOT!!!!! I can imagine just getting within about thousands of miles from the sun and it will probably be about 1,000 degrees Fahrenheit.

    • You’re right, it’s one hot place to be, Tyler! The sun feels hot even from Earth, so it’s important for those studying space to keep their distance from the sun! Thanks for sharing your comment! :)

  14. Special greetings to you, Wonderopolis. To get started with my response, I founded that after analyzing the blazing question of the day I became extremely intrigue and interested in the facts and details of the paragraphs. Especially the fact that the sun’s center core can reach up to inferno temperature of about 27,000,000 degrees!!! I am really satisfied at the abundance amount work you put into every single question that appeared.I also appreciate this website progress and evolution. Every day I would still be eager and enthusiastic to read your videos even when I am uninterested in them.Keep up the good quality questions!!!

    • Hello there, Calvin, thanks for WONDERing with us today! We’re so glad you shared when you learned about the heat of the sun- way to go, Wonder Friend! We are super excited that you enjoy all the Wonders we have to offer, it’s lots of fun to learn cool new facts at Wonderopolis! Who knows what Wonder will be next, but it sure will be fun! See you soon, Calvin! Thanks for sharing your comment today! :)

  15. This topic relates to the topic we are learning about in science. I WONDER how hot the earth’s core is compared to the suns core? How do the scientists find out how hot the sun really is, or do they just predict?

    • Hi Tyler! Thanks so much for WONDERing with us today! We imagine the sun’s core is much hotter than the earth! Keep WONDERing! :)

  16. We would like to know how the sun gets so hot? We learned that it is very hot on the sun. We also learned the sun is made of gas. We learned the sun has different colors besides yellow. We saw red, yellow, and orange!

    • WONDERful WONDERing from Ms. Phillips’ Class! We are so glad that you learned something new today! Thanks for WONDERing with us! :-)

    • Hi there, Wonder Friend Jordan! We don’t think the sun is going to blow up. Thanks for visiting Wonderopolis today! :)

    • We agree, the sun sure is hot, Tyler! Nuclear fusion is the reason the sun is SO hot! Thanks for joining us to WONDER today! :)

    • Thank you for all your NICE words, Wonder Friend Ermis! They’ve made our day her in Wonderopolis! We’re SO glad you spent time with us today WONDERing! :)

    • Thanks for letting us know that this song reminded you of a song, Calub! We hope you WONDER with us again soon! :)

    • We think learning about the sun and space is a favorite part of science, too, Werd. What did you like learning about the sun while reading today’s Wonder? We hope you have a WONDERful week! :)

    • Hello, Wonder Friend Logan. We think that’s AWESOME that you spent time WONDERing and thinking about what it would be like to be close to the sun. We hope you join us to WONDER again soon! :)

    • Welcome back, Wonder Friend Kevin! Indeed the sun is EXTREMELY hot. We wouldn’t want to get anywhere near it! Thanks for visiting Wonderopolis today! :)

    • FANTASTIC question, Wonder Friends in Mrs. Noffke’s Summer School Class! :) We checked out several sources and they estimate that the inner core of the Earth is between 9,000 and 13,000 degrees Fahrenheit. So… We ask you, how does that compare to the sun? Happy WONDERing! :)

  17. As usual a good posting. One comment though: it would be useful to have the temperatures also listed in Celsius. Although I realize this is an U.S. site, teachers from other countries are less willing to use it if the most commonly used temperature scale is not included (even in brackets?).
    Don’t view this as a negative comment, just a suggestion.

    • Thanks for joining us to WONDER today, Locksloy. We have Wonder Friends all over the World! We are always trying to improve and this is something we will take into consideration in the future. We appreciate your feedback and suggestion. :)

  18. I never knew that. I wish I can feel it. Is it fluffy. Why is it changes the colors when you look at from the earth?


    • We’re so happy you’re here today with us, Wonder Friend Bria!. Thanks for visiting us and learning something new! :)

    • HOORAY, Sanela! That makes our day here in Wonderopolis to know that you enjoy reading our Wonders! We hope to see you back here soon and be sure to leave us a comment! :)

    • Thanks for another AWESOME comment, Brandon! The sun is the hottest thing in the solar system. We LOVE having you WONDERing with us! :)

  19. Hi, Wonderopolis! We think it is weird that all lava is cooler than the sun! We think it is weird because lava is very hot and so is the sun. So why can’t they be the same? Another reason is the hottest lava on Earth is a whopping 10,000 degrees Fahrenheit! But, you’ve taught us that the hottest part of the sun is 3.6 million degrees Fahrenheit! In conclusion, thanks for the new information!
    Thanks! -C + H

    • Thanks for visiting Wonderopolis and sharing your comment with us, C + H! It’s fascinating to think about the immense heat of both lava and the sun! We’re glad you learned some new things with us! :)

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Have you ever wondered…

  • How hot is the sun?
  • What is the sun made of?
  • Where is the hottest part of the sun?

Wonder Gallery

the sun_shutterstock_69675613Vimeo Video

Try It Out

Whew! Today’s Wonder of the Day really heated things up, didn’t it? Well, we say pour it on! Let’s get things even hotter as you explore one or more of the following activities with a friend or family member:

  • So how hot is hot? You’ll need a thermometer for this fun exercise. Learn to gauge the temperature of various items from your own personal experience. You’ll need samples of a few different liquids of different temperatures. You may want to get help from an adult, too, as this will be more fun if you use the stove and microwave to heat up some water. Find samples of various liquids, such as tap water at room temperature, milk from the refrigerator, the coldest water you can get from the tap, the hottest water you can get from your shower, some water that has been microwaved for 10, 20, 30 or more seconds, and some boiling water. Make a list of all of these items and your guess as to what temperature they are. Then use your thermometer to measure their exact temperatures. How accurate were your guesses? What was the coldest liquid? What was the hottest? How does the hottest liquid compare to the heat of the sun’s core?
  • Now that you have a good idea how hot the sun is, it’s time to think about how to protect your body from the sun’s harmful rays. You should also know what to do if you do happen to get a sunburn. If you’re going to be out in the sunshine, you should wear sunglasses and use sunscreen. This is especially true if you’re going to be out in the sun for a long time, such as a day at the beach. Make sure you lather up with plenty of sunscreen and put more on every two hours. If you’re exercising or sweating a lot, you’ll need to apply sunscreen more often. Sunscreens come in many different varieties. There should be a Sun Protection Factor (SPF) number listed on the bottle. Try to use a sunscreen with an SPF of at least 15. The higher the SPF number, the more protection from the sun the sunscreen provides. If you’re prone to sunburn, you might want to consider taking other steps to protect your skin. Wearing long-sleeved shirts, hats and sunglasses can help reduce your exposure to the sun. If you do happen to get a sunburn, there’s not much you can do to make your skin heal quickly. The best thing you can do is treat your symptoms and give your skin time to heal. Keep your sunburned skin cool with damp towels or by taking cool baths. You should also keep sunburned areas moist by using moisturizing creams with aloe. Most drugstores carry special lotions to use for sunburns. If you find that you have a severe sunburn, you should consult a doctor. Signs of a severe sunburn include multiple blisters, as well as headaches and nausea. If you have just a few blisters, you probably don’t need to see a doctor. Just don’t break them. Breaking blisters slows the healing process and increases your risk of infection.
  • Up for a challenge? Earth is a comfortable place to live in our solar system, because of its distance from the sun. But what about life on those planets closer to the sun? Do some Internet research on your own to find out what life would be like on Mercury and Venus. What is their weather like compared to that on Earth? How hot and cold does it get? Could a human survive on those planets? Why or why not? Share your findings with your friends and family members.

Still Wondering

Check out Science NetLinks’ The Warmth of the Sun lesson to learn more about the sun’s critical role in warming the land, air and water around you.


Test Your Knowledge

Wonder What’s Next?

Ever wonder what life would be like on a spaceship? Find out tomorrow in Wonderopolis!

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