Students get answers to questions about how planets form, how gravity works and what keeps the sun shining.


(Ota Lutz, NASA/JPL Education Specialist)
Teachers would often like their students to be able to ask questions of a scientist.
Today we have a teacher and some students in Glendale, Calif., with questions on the solar system.

Glendale, would you like to introduce yourselves?

(Mrs. Pascale-Parra, Teacher)
Hi, My name is Mrs. Pascale-Parra and I teach at Roosevelt Middle School in Glendale, Calif. I teach 8th grade science and some of my students have questions for a scientist.

(Ota Lutz)
Well we just happen to have in the studio with us today Varoujan, who is a scientist on the Spitzer Space Telescope. So, Roosevelt, hit us with your questions.

Hello, I'm Anaiah and my question to you is how were all the planets formed in the beginning?

(Varoujan Gorjian, Scientist, Spitzer Space Telescope)
Basically our solar system formed from a giant ball of gas. Part of it became a little bit denser and then that started collapsing. The gravity of it started bringing in more gas and in this gas, there's a little bit of dust in this thing. So the center part of that gas becomes our sun and then there's a disk of this dust that forms around it and slowly these little bits of dust hit each other and they become bigger dust grains and then they hit each other some more and they become little pebbles. And as it gets bigger and bigger, it starts attracting more and more pebbles so then it becomes boulders and the boulders hit each other and become bigger boulders and eventually that's how the planets formed.

Hi, my name is Gor and my question is how does the Earth move? What keeps it going?

(Varoujan Gorjian)
Everything in space moves and the Earth formed as part of this moving disk of dust and gas around our sun.  As it was contracting, like a skater pulling her arms in, it starts moving faster and faster and now the Earth is moving fast enough so that it doesn't fall into the sun. Basically it's going around the sun in its orbit and the reason why it doesn't slow down, you know if you roll a ball it'll slow down, that's because there's friction. But in space, it's a vacuum, there's nothing to rub against so there's nothing to slow the Earth down so there's nothing that needs to keep it going like a motor or an engine.

How come gravity never stops working?

(Varoujan Gorjian)
Well gravity isn't something that has to keep working. Gravity is a property of anything that has mass. A proton has gravity, it's one of the smallest particles around and you have gravity, a ball has gravity, anything that has mass, has gravity.

My name is Jessica and my question is what keeps the sun on fire?

(Varoujan Gorjian)
We get light and heat from the sun like we get from fire. The sun isn't on fire in the same way that we understand fire. Fire is what's called a chemical process, say you have wood on fire, it has carbon in it. The oxygen and the carbon combine and share electrons and that gives off the light and the heat. The sun is very different. It has a nuclear process. It takes elements and changes them by combining them. Their nuclei come together in a process called fusion and that process releases all that energy, which gives us the heat and the light from the sun.

Does the sun ever run of fuel?

(Varoujan Gorjian)
The sun can run out of fuel and it will run out of fuel. No worries, it's about 5 billion years from now. But the main thing is it's all about fuel and when a star runs out of fuel like any other kind of generation process, it will not be able to produce that energy anymore.

(Ota Lutz)
Well thank you guys again for your questions and we will see you around.

(Mrs. Pascale-Parra and students)
Bye, thank you.

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