Ready Jet Go
Gravity
Clip | 1m 31sVideo has Closed Captions
Astronomer Amy Mainzer talks about gravity and how we use rockets to get into space.
Why can't we just jump to get into space? Astronomer Amy Mainzer talks about Earth's gravity and how we use rockets and rocket fuel to get into space.
Problems playing video? | Closed Captioning Feedback
Problems playing video? | Closed Captioning Feedback
Ready Jet Go
Gravity
Clip | 1m 31sVideo has Closed Captions
Why can't we just jump to get into space? Astronomer Amy Mainzer talks about Earth's gravity and how we use rockets and rocket fuel to get into space.
Problems playing video? | Closed Captioning Feedback
How to Watch Ready Jet Go
Ready Jet Go is available to stream on pbs.org and the free PBS App, available on iPhone, Apple TV, Android TV, Android smartphones, Amazon Fire TV, Amazon Fire Tablet, Roku, Samsung Smart TV, and Vizio.
Do you think it'’ll work if I just jump?
- You'’re gonna have to jump a lot harder than that, I think.
- Oh, bummer.
- [laughs] - Hi, I'’m astronomer Amy Mainzer.
And I'’m here with Sandy Simmons at SpaceX.
Sandy, why can'’t I just jump to get into space?
- The Earth is very large, and it has a lot of mass, so we have very strong gravity that hold us to the surface of the Earth, so you can'’t just jump.
- I guess the Earth is really big, and that does mean it has a lot of stuff... - Exactly.
- Which means a lot of gravity.
- Mm-hmm.
If you want to get up into space, I would recommend using a rocket.
- Rockets are how we get into space, and we'’ve been using them for a long time.
Rocket fuel is ignited, which makes it burn.
The heat and flames push down, and the rocket goes up.
How big of a rocket would I need if I wanted to get something the size of, say, me into space?
- Even for something of very small size, we would actually need to send out tens of thousands of gallons of fuel to launch someone up into orbit into space.
- The fuel'’s heavy, too, isn'’t it?
- Exactly.
- If we have to burn fuel to get stuff up into space and the fuel'’s heavy, that means we have to add more fuel, right?
- Yep.
Essentially, we just bring a lot of fuel with us.
- I guess it gets a little easier as we go, right?
Because as we go up and we burn fuel, the rocket gets lighter, right?
- Exactly, it gets a lot lighter as you go up.
Unfortunately, we have to bring all of it with us at the beginning, because there'’s no gas stations on the way to space.
- It'’s a lot fuel, though.
Wow.
- Exactly.
- So the next time you'’re jumping up and down trying to launch yourself into space, you might want to consider using a rocket.
Sandy, do you think you could help me with that?
- Sure.
Why not?
- Okay, let'’s go.
Support for PBS provided by: