More dumbness: How does 'gravity assist' work?
- Rum
- Absent Minded Processor
- Posts: 37285
- Joined: Wed Mar 11, 2009 9:25 pm
- Location: South of the border..though not down Mexico way..
- Contact:
More dumbness: How does 'gravity assist' work?
Was thinking of this as I was watching a Youtube on one of the probes out there.
They use the gravity of a planet to 'slingshot' around and give the probe a boost in speed.
BUT - where does the energy come from? You can't get something for nothing energy wise. To me it seems logical that the acceleration increase as the probe is 'pulled' into the planet should be lost as it escapes the gravity and is 'slowed'.
What am I missing - other than the brain cells for maffs?
They use the gravity of a planet to 'slingshot' around and give the probe a boost in speed.
BUT - where does the energy come from? You can't get something for nothing energy wise. To me it seems logical that the acceleration increase as the probe is 'pulled' into the planet should be lost as it escapes the gravity and is 'slowed'.
What am I missing - other than the brain cells for maffs?
- Seabass
- Posts: 7339
- Joined: Sun Jan 30, 2011 7:32 pm
- About me: Pluviophile
- Location: Covidiocracy
- Contact:
Re: More dumbness: How does 'gravity assist' work?
That the planet is moving. Energy will be gained or lost depending on whether the probe moves with or against the planet's orbit.
"Those who can make you believe absurdities, can make you commit atrocities." —Voltaire
"They want to take away your hamburgers. This is what Stalin dreamt about but never achieved." —Sebastian Gorka
"They want to take away your hamburgers. This is what Stalin dreamt about but never achieved." —Sebastian Gorka
- laklak
- Posts: 20984
- Joined: Tue Feb 23, 2010 1:07 pm
- About me: My preferred pronoun is "Massah"
- Location: Tannhauser Gate
- Contact:
Re: More dumbness: How does 'gravity assist' work?
You just ask gravity nicely for a little help.
Yeah well that's just, like, your opinion, man.
- L'Emmerdeur
- Posts: 5709
- Joined: Wed Apr 06, 2011 11:04 pm
- About me: Yuh wust nightmaya!
- Contact:
Re: More dumbness: How does 'gravity assist' work?
Seabass covered it. The spacecraft 'steals' or adds a minuscule percentage of the planet's kinetic energy (orbital velocity) to either speed up or slow down. For a much more long-winded explanation, see 'Gravity assist'.
- pErvinalia
- On the good stuff
- Posts: 59357
- Joined: Tue Feb 23, 2010 11:08 pm
- About me: Spelling 'were' 'where'
- Location: dystopia
- Contact:
Re: More dumbness: How does 'gravity assist' work?
Cool! I've never actually bothered to think about how gravity assist might work.
Sent from my penis using wankertalk.
"The Western world is fucking awesome because of mostly white men" - DaveDodo007.
"Socialized medicine is just exactly as morally defensible as gassing and cooking Jews" - Seth. Yes, he really did say that..
"Seth you are a boon to this community" - Cunt.
"I am seriously thinking of going on a spree killing" - Svartalf.
"The Western world is fucking awesome because of mostly white men" - DaveDodo007.
"Socialized medicine is just exactly as morally defensible as gassing and cooking Jews" - Seth. Yes, he really did say that..
"Seth you are a boon to this community" - Cunt.
"I am seriously thinking of going on a spree killing" - Svartalf.
- Clinton Huxley
- 19th century monkeybitch.
- Posts: 23739
- Joined: Mon Mar 02, 2009 4:34 pm
- Contact:
Re: More dumbness: How does 'gravity assist' work?
Gravity assist is theft. Like tax.
"I grow old … I grow old …
I shall wear the bottoms of my trousers rolled"
AND MERRY XMAS TO ONE AND All!
http://25kv.co.uk/date_counter.php?date ... 20counting!!![/img-sig]
I shall wear the bottoms of my trousers rolled"
AND MERRY XMAS TO ONE AND All!
http://25kv.co.uk/date_counter.php?date ... 20counting!!![/img-sig]
- laklak
- Posts: 20984
- Joined: Tue Feb 23, 2010 1:07 pm
- About me: My preferred pronoun is "Massah"
- Location: Tannhauser Gate
- Contact:
Re: More dumbness: How does 'gravity assist' work?
Illegal earth immigrants stealing Jupiter's gravity. They should build a wall.
Yeah well that's just, like, your opinion, man.
- Hermit
- Posts: 25806
- Joined: Thu Feb 26, 2009 12:44 am
- About me: Cantankerous grump
- Location: Ignore lithpt
- Contact:
Re: More dumbness: How does 'gravity assist' work?
And an illustration/explanation needing no words at all, courtesy the Wikipedia.L'Emmerdeur wrote: ↑Fri Jun 29, 2018 6:32 pmSeabass covered it. The spacecraft 'steals' or adds a minuscule percentage of the planet's kinetic energy (orbital velocity) to either speed up or slow down. For a much more long-winded explanation, see 'Gravity assist'.
I am, somehow, less interested in the weight and convolutions of Einstein’s brain than in the near certainty that people of equal talent have lived and died in cotton fields and sweatshops. - Stephen J. Gould
- pErvinalia
- On the good stuff
- Posts: 59357
- Joined: Tue Feb 23, 2010 11:08 pm
- About me: Spelling 'were' 'where'
- Location: dystopia
- Contact:
Re: More dumbness: How does 'gravity assist' work?
That doesn't really answer his question, unless you can discern a speed difference after the object passes the planet.
Sent from my penis using wankertalk.
"The Western world is fucking awesome because of mostly white men" - DaveDodo007.
"Socialized medicine is just exactly as morally defensible as gassing and cooking Jews" - Seth. Yes, he really did say that..
"Seth you are a boon to this community" - Cunt.
"I am seriously thinking of going on a spree killing" - Svartalf.
"The Western world is fucking awesome because of mostly white men" - DaveDodo007.
"Socialized medicine is just exactly as morally defensible as gassing and cooking Jews" - Seth. Yes, he really did say that..
"Seth you are a boon to this community" - Cunt.
"I am seriously thinking of going on a spree killing" - Svartalf.
- Rum
- Absent Minded Processor
- Posts: 37285
- Joined: Wed Mar 11, 2009 9:25 pm
- Location: South of the border..though not down Mexico way..
- Contact:
Re: More dumbness: How does 'gravity assist' work?
I think the first one does, even if the increase in speed is not all that apparet - gives the idea well enough though.pErvinalia wrote: ↑Sat Jun 30, 2018 5:32 amThat doesn't really answer his question, unless you can discern a speed difference after the object passes the planet.
- pErvinalia
- On the good stuff
- Posts: 59357
- Joined: Tue Feb 23, 2010 11:08 pm
- About me: Spelling 'were' 'where'
- Location: dystopia
- Contact:
Re: More dumbness: How does 'gravity assist' work?
I can't see any speed increase. And I really want to push Hermit's buttons too.
Sent from my penis using wankertalk.
"The Western world is fucking awesome because of mostly white men" - DaveDodo007.
"Socialized medicine is just exactly as morally defensible as gassing and cooking Jews" - Seth. Yes, he really did say that..
"Seth you are a boon to this community" - Cunt.
"I am seriously thinking of going on a spree killing" - Svartalf.
"The Western world is fucking awesome because of mostly white men" - DaveDodo007.
"Socialized medicine is just exactly as morally defensible as gassing and cooking Jews" - Seth. Yes, he really did say that..
"Seth you are a boon to this community" - Cunt.
"I am seriously thinking of going on a spree killing" - Svartalf.
- JimC
- The sentimental bloke
- Posts: 73101
- Joined: Thu Feb 26, 2009 7:58 am
- About me: To be serious about gin requires years of dedicated research.
- Location: Melbourne, Australia
- Contact:
Re: More dumbness: How does 'gravity assist' work?
Velocity includes both speed and direction. A change in velocity without a change in speed still counts - without a planet's gravity assist, a change in direction would require a fuel-using burn.
Speed increases, as described earlier, borrow some of a planet's kinetic energy.
Speed increases, as described earlier, borrow some of a planet's kinetic energy.
Nurse, where the fuck's my cardigan?
And my gin!
And my gin!
- pErvinalia
- On the good stuff
- Posts: 59357
- Joined: Tue Feb 23, 2010 11:08 pm
- About me: Spelling 'were' 'where'
- Location: dystopia
- Contact:
Re: More dumbness: How does 'gravity assist' work?
Still counts as what? Rum's OP is talking about speed, not velocity.
Sent from my penis using wankertalk.
"The Western world is fucking awesome because of mostly white men" - DaveDodo007.
"Socialized medicine is just exactly as morally defensible as gassing and cooking Jews" - Seth. Yes, he really did say that..
"Seth you are a boon to this community" - Cunt.
"I am seriously thinking of going on a spree killing" - Svartalf.
"The Western world is fucking awesome because of mostly white men" - DaveDodo007.
"Socialized medicine is just exactly as morally defensible as gassing and cooking Jews" - Seth. Yes, he really did say that..
"Seth you are a boon to this community" - Cunt.
"I am seriously thinking of going on a spree killing" - Svartalf.
- JimC
- The sentimental bloke
- Posts: 73101
- Joined: Thu Feb 26, 2009 7:58 am
- About me: To be serious about gin requires years of dedicated research.
- Location: Melbourne, Australia
- Contact:
Re: More dumbness: How does 'gravity assist' work?
Velocity would be a better term in the OP - we are talking about rocket-powered spacecraft, and any change in velocity (speed and/or direction) without gravity assist uses up reaction mass. In finding a path from Earth to the future position of a planet or moon, one wants that path to use the minimum amount of reaction mass. Some paths of that nature use multiple fly-bys of planets, using each encounter to either change direction without using fuel, or to increase the speed (relative to the Sun) by stealing KE from a planet. I gather calculations of such paths are very intricate, taking much computer time...pErvinalia wrote: ↑Sat Jun 30, 2018 7:58 amStill counts as what? Rum's OP is talking about speed, not velocity.
Nurse, where the fuck's my cardigan?
And my gin!
And my gin!
Who is online
Users browsing this forum: No registered users and 13 guests