Can a pair of identical twins help people travel to space? In recognition of “World Space Week”, Bruce Gulland and Liz Waid tell about an interesting study that shows the effect of space travel on people.

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Welcome to Spotlight. I’m Bruce Gulland.

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And I’m Liz Waid. Spotlight uses a special English method of broadcasting. It is easier for people to understand, no matter where in the world they live.

Click here to follow along with this program on YouTube.

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It is 2015. A rocket ship stands upright in a large field. The technicians inside have made sure it is safe. And now, a yellow flame begins to glow underneath the rocket. The ship rises from the ground.

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Inside, the astronauts prepare themselves for a difficult ride. The speed of the rocket is pushing them back against their chairs, so that they cannot move. Even the skin on their faces gets pushed back. But soon, the ship passes through the earth’s atmosphere and finally into space. There is less gravity here. So, the astronauts begin to float off their seats. Only their seatbelts hold them back.

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One of these astronauts is named Scott Kelly. Soon, he and the others will arrive at the international space station, or ISS. They are bringing supplies. And they will help run the station. But Kelly’s trip is special. Many of the others will be at the station a few months. But Kelly will be in space for an entire year. Today’s Spotlight is on Scott Kelly’s year in space and what that might mean for future space travel.

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Today, many people have been to space. Some have even lived there longer than Scott Kelly. Valeri Polyakov was a Russian Cosmonaut. He stayed at the ISS for almost 14 months! But still, scientists do not know much about what happens to a person’s body when they go to space. This is why Scott Kelly is so important. He is an identical twin.

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Scott Kelly has a brother named Mark Kelly. They look almost exactly alike – they are identical. But, most importantly, they have the same genes. Scientists examined the twins before Scott went to space. When he was in space, Scott sent the scientists genetic samples. And, when he came back, they examined both twins again. They could then compare the results. They could compare, scientifically, what space did to Scott’s body.

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Space is a very different environment than Earth. And human bodies are not very used to it. Most of this has to do with the lack of gravity. Living without gravity would be very strange for most of us. For example, you cannot drink from a cup in space. Water will not stay inside. Water floats in a ball in the open. Instead, you must drink from a pouch, or a straw. Using the toilet can also be a messy business. People on the ISS have special machines to capture their waste. Otherwise, it would float around, and contaminate the environment.

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But living in space means more than just changing your environment. It actually changes a person’s body. When Scott Kelly entered the ISS, there was no gravity pushing down his spine. So, his spine got longer. In space, he was about three centimetres taller than on earth. He also did not have to use his muscles much. In space, you can float in one direction just by lightly kicking a wall. Or you can guide yourself with your hands. This sounds very fun. But it also means muscles atrophy and lose their power to move. If a person were to go from space to earth, it would be very difficult for them to move. So, people living in space must exercise a lot. This also keeps their bones strong and healthy.

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But other changes happened to Scott Kelly that no one had seen before. The way his genes worked changed. People’s genes do not change. But a person’s environment can change what those genes do. Scientists call this gene expression. If a person is in a very stressful environment, different genes will express themselves. Scott Kelly was in a very strange environment. So his genes started expressing themselves differently. Christopher Mason is a professor at Weill Cornell Medicine. He also helped study Scott and Mark. He spoke about the study at a conference.

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“As soon as Scott got into space there was a huge change in over 1000 genes that are changing a lot. So clearly the body and cells were adapting to this new environment of space.”

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Few of these changes hurt Scott Kelly. Some even made his immune system stronger. But being in space for a year did have some negative effects. The shape of his eyes changed. His vision got worse. His blood vessels became swollen. He got greater risk of heart disease. Scott also encountered some radiation in space. This means he has a higher risk for cancer.

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After 340 days, Scott Kelly returned to earth. But even after he left space, scientists continued studying him. Most of the changes did not last long. Some of his DNA was damaged. And, he had a harder time thinking as quickly as before. But several months afterward, he reported feeling normal again.

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These results are very important for future space travel. Not everyone’s bodies will change like Scott’s. Space affects everyone differently. It even affects women differently than men. But Scott Kelly’s year in space will help predict things that might go wrong. And it can help prevent these problems in the future.

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Some people want to go even farther into space – maybe to distant planets or other solar systems. But there may be some danger in going to space. It is difficult to understand how the body might change even farther from earth. People traveling to other planets would be in space even longer. And they would encounter a lot of radiation. But probably, this will not stop the next generation of explorers. Space is just too strange. And what you might find there is too interesting. Scott Kelly has retired from NASA. But he still wants to go to space. John Logsdon is a historian. He studies the history of space travel. He spoke to Scott Kelly in 2018 about what it is like in space. Kelly said:

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“Space is the most joyous and magical place I could think of.”

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Would you go to space if you could? Why, or why not? Do you think people should travel into space? You can leave a comment on our website at You can also find us on YouTube, Facebook, Instagram, and Twitter.

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The writer of this program was Dan Christmann. The producer was Michio Ozaki. The voices you heard were from the United Kingdom and the United States. All quotes were adapted for this program and voiced by Spotlight. This program is called: A Year in Space.

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Visit our website to download our free official app for Android and Apple devices. We hope you can join us again for the next Spotlight program. Goodbye.


Do you dream of going to space? Do you think people should travel to space? Why or why not?

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Join the discussion

  • Thanks for giving this interesting information about the space.
    My 8 year old son often asks me where the space ends and what there would be outside the solar system.
    I answer him the space never ends and maybe there would be another solar system outside ours. Is it right?

    • That’s right! According to NASA, “Our planetary system is the only one officially called “solar system,” but astronomers have discovered more than 3,200 other stars with planets orbiting them in our galaxy.”

  • Thank you for this interesting episode!
    To be honest, before a listen to you I would like If I could go to the space. It’s seems a big adventure and impressive!
    But now I feel a bit afraid about the negative effects. Yes, I know, like you said It doesn’t mean that It happens to everyone, but generally I don’t have a strong desire to try It. I just curious about It.

    Thanks again.
    Your podcast my favorite, keep going!❤️

  • oh! i do not know the reason why i can not open the video to listen to as normal
    i try by my computer and phone but fail
    who else look like me?

  • Of course I would travel to space, because I have wanted to be an astronaut since I was a little girl, space is a strange place but there are many things to discover, as Scott Kelly said, it is a magical place, that always makes us wonder what is out there, I would like to make more discoveries and help NASA as Scott Kelly did, maybe I can find a way to not be so affected by the lack of gravity in space.

  • I would surely would, it’s a magical, wide and extensive space VERY EXTENSIVE. Iam not really a fan of thinking what’s the purpose of life, but I think human were created to explore what wouldn’t cross people’s minds. No one knows what they would find there, and that’s what makes it interesting ☄️

  • Humans evolved on Earth. Space is not a natural place for man. There are negative effects of being in space – muscle wasting, radiation , DNA damage. Our science is undeveloped. Travel to other planets outside our solar system is not possible due to the large distances. We need to build a ship that travels at the speed of light. Now that’s impossible. I do not think we will colonize our galaxy in our lifetime.

  • I would visit space but I’m worrying about changing my genes if they have some way to save my genes I will do ,because I think it’s something interesting

  • absolutely, I think it would be an interesting experiment and you would be a special person in your country, and I see the people who want to go to space should not stay a lot because it is a risky experience

  • Distances in the universe are measured in light years and the speed of light cannot be exceeded. Man too has limits that cannot be overcome. It is true that every four years at the Olympics we see old records crumble, but the time will come when performance records can no longer be broken by the human body, instead the forces of the mind have no limits. The desire for knowledge is part of man and cannot be erased, therefore we cannot predict the future. Traveling in space is very uncomfortable, it goes slowly and you can’t go too far, but luckily we have the thought machine which is faster and can go much further. It is thought that makes things exist. When thought is turned off, the world disappears into darkness. All the beauty in the world is in the thoughts of those who see things. With the wings of imagination you can go where no spaceship can go.

  • Yes, I would like to go to the space to see how it looks , to see the planets and stars around me , and most importantly to experience the movement without gravity, it would be pretty amazing and joious experience .

  • Yes I would to travel to speace and being with an astronet I would to being without gravity and see the things flying , it is nice experiment to spend several of days above the erthe insid the speace .

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