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What makes gravity, gravity?

Lars

By Lars
in Physics

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Lars

Lars

Posted
Posted

Im not too sure how to word this so hang with me :rolleyes:

 

Well, my year. 8 science teacher is not the brightest bulb in the box, but he absouloutly stumped me with a question today; "Why is gravity there?". Is there even an answer for this? If I dont get a good answer by monday I have a lunch time clean up (long story). Am I crazy or is that an impossible task to set (especially for an 8th grader). :confused:

swansont

swansont

Posted
Posted

From a Newtonian perspective, it's caused by mass (The general relativity explanation is more complicated). But why mass causes gravity isn't something that has been answered, AFAIK. We just know that it does.

the tree

the tree

Posted
Posted

An awnser (not the awnser, because no-one is anywhere near sure) involves one hell of a stupid word: gravitons which as far as I understand is held by the "strong force" (another insanely stupid word, QM is full of them) around particles that have mass and subsequently bring others in. Or at least that is one model.

 

At most peoples level, even that of a physics teacher, it's fairly easy to say that things that have mass just do exert a on, other things (that don't have to have mass themselves, this confuses me as well).

 

Anotherother fun questions that a lot of teachers wont the awnsers to is: "If I shake this string then I get a wave of string but, what is light a wave of?", the awnser is that it isn't. Which really amuses me for some reason.

cpwmatthews

cpwmatthews

Posted
Posted

What if gravity was not a downward pull but a downward force? Say that particles from our atmosphere are attracted to the centre of the earth and exert some downward motion, crazy maybe,

Lars

Lars

Posted
  • Author
Posted

That is what I was thinking last night, But where does the force come from? Gravity is stupid :-(

cpwmatthews

cpwmatthews

Posted
Posted

There are particles, and you must forgive my idiousy, that are constantly falling on our planet, the hell if I can remember the name, Nutrinos?? Any way what we do know about gravity is that it acts all around the earth but do we know if gravity exerts the same force at every point around the earth i.e. north south e.t.c.? We know gravity is less in space so from that we can concur that our atmosphere also plays a part in increasing it's effects. but the one fact that is obvious is that it is always connected to the centre of what ever planet you are on, what do you think?

the tree

the tree

Posted
Posted
What if gravity was not a downward pull but a downward force?
Ignoring the "downward" thing, gravity is a force.
Say that particles from our atmosphere are attracted to the centre of the earth and exert some downward motion
What makes you think they aren't/don't? Why wouldn't they?
But where does the force come from?
You want something more precise than "from gravitons"?
Gravity is stupid
Without gravity, there'd be much less to prevent the increase of energy and the universe would be drawn to it's heat-death much sooner. Basically, the whole would just be damn boring. We wouldn't even have stars.
Any way what we do know about gravity is that it acts all around the earth
We know an awful lot more than that.
but do we know if gravity exerts the same force at every point around the earth i.e. north south e.t.c.?
No it doesn't.
We know gravity is less in space so from that we can concur that our atmosphere also plays a part in increasing it's effects.
WHAT THE HELL?!?!? Where oh where is your logic there? Our atmostphere is prone to exactly the same rules as all other matter and there is no reason why it shouldn't be.
but the one fact that is obvious is that it is always connected to the centre of what ever planet you are on, what do you think?
That gravity isn't, and never was confined to planets?
ajb

ajb

Posted
Posted

Physics cannot put and answer to "why", but tells you "how". Gravity is observed in nature, falling apples, the motion of planets etc..

 

What coures gravity is mass/energy. It plays the same role as electric charge does in electrostatics. If things have no net charge then their is no electric force between them. The same is true of gravity, no mass or energy then no gravitational force.

 

Or are you really asking "why gravity is not just electromagnetic in nature"?

bascule

bascule

Posted
Posted
That is what I was thinking last night, But where does the force come from? Gravity is stupid :-(

 

The answer in general relativity is that objects with mass bend/warp the space around them, causing nearby objects to be attracted to them.

  • 4 weeks later...
KaiduOrkhon

KaiduOrkhon

Posted
Posted
Im not too sure how to word this so hang with me :rolleyes:

 

Well' date=' my year. 8 science teacher is not the brightest bulb in the box, but he absouloutly stumped me with a question today; "Why is gravity there?". Is there even an answer for this? If I dont get a good answer by monday I have a lunch time clean up (long story). Am I crazy or is that an impossible task to set (especially for an 8th grader). :confused:[/quote']

 

Perhaps you've answered your science teacher's doubletalking question best in commenting that he's not the brightest bulb in the box. His question translates to the question of 'Why?', squared, applied to FILL IN HERE, squared? You might try asking him to rephrase his question, or, perhaps reply with 'Why do you ask?' ('Why' tends more toward theology than hard science)

  • 1 year later...
Lars

Lars

Posted
  • Author
Posted

Haha, sorry to bring back an old thread, but I posted this last year, I didnt end up getting a clean up detention, but what's funny is I didnt even realise I had this account until I tried to sign up again :D

ironizer

ironizer

Posted
Posted
If gravity is a result of an attraction resulting from mass, then why aren't fat girls more popular than thin girls?

 

Because thin girls make guys more horny (usually). The gravitational force between a guy and a fat chick is greater, but most of us have the ability to escape it.

insane_alien

insane_alien

Posted
Posted
Because thin girls make guys more horny (usually). The gravitational force between a guy and a fat chick is greater, but most of us have the ability to escape it.

 

In my experience it is usually a matter of taste than of gravity, or the horniness of the woman.

 

for instance, really skinny is just as disgusting and off putting as really fat. a happy medium is best.

  • 2 months later...
Ashish

Ashish

Posted
Posted

Anotherother fun questions that a lot of teachers wont the awnsers to is: "If I shake this string then I get a wave of string but, what is light a wave of?", the awnser is that it isn't. Which really amuses me for some reason.

 

really thats the question which has disturbed my mind. And I'm to satisfied with you. And i'm in search of it.....................

CaptainPanic

CaptainPanic

Posted
Posted

Since nobody seems to know what gravity exactly is (has anyone ever measured a "graviton" or something like that?), and why it's there... It might be a safe conclusion to say that gravity is merely a model that seems to fit our observations very well.

 

I cannot think of a reason why there shouldn't be another model, without gravity included, that can describe the reality that we measure and see with our eyes. However, such model has not been developed yet, so we assume gravity to be real. It also feels very real when you go head first to the pavement.

 

There are some people who have interesting arguments that say the gravity model is incomplete (they don't seem to disagree with the concept of gravity). They have grouped themselves in a movement (if you can call it that) called "the electric universe". I have read some electric universe webpages (just google it)... and hardcore models seem hard to find on websites. However, in more conventional websites, I also have never seen a good explanation why Saturn's rings don't condense into some spheres (moons). A ring seems to defy gravity. Electric forces can explain rings quite well, since it includes both attraction and repulsion. Gravity, to my knowledge, only includes attraction. If anyone has a good explanation about Saturn's rings, I'm interested.

 

Disclaimer: I have not studied the subject to a great detail. Before stating things I wrote here as a fact, please study the subject, and doublecheck everything. (Ha, quite proud of myself for adding a disclaimer here ;) ).

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