Does a spaceship float or fly?

[RB Will]

Had this thought while walking the dog.
I was thinking they are not really flying as in creating lift with wings

[ewenm]

Neither. As you say flying suggest creating lift and floating suggest being bouyant in a fluid.

[RB Will]

So what does a space ship do?

[Odie]

RB Will said:

So what does a space ship do?

Beats the living st outa gravity using explosives

[ewenm]

RB Will said:

So what does a space ship do?

Most of our spaceships orbit something (Earth, Moon, other planets, the Sun).

Edit: I don't know what the term is for something moving in a relatively weak gravitational field. Gliding? Drifting? Inertia-ing?

Edited by ewenm on Thursday 14th June 13:37

[rhinochopig]

Odie said:

Beats the living st outa gravity using explosives

[VernalEquinox]

RB Will said:

So what does a space ship do?

Falls.

[Hugo a Gogo]

ewenm said:

RB Will said:

So what does a space ship do?

Most of our spaceships orbit something (Earth, Moon, other planets, the Sun).

Edit: I don't know what the term is for something moving in a relatively weak gravitational field. Gliding? Drifting? Inertia-ing?

Edited by ewenm on Thursday 14th June 13:37

falling

[ewenm]

Hugo a Gogo said:

falling

Yeah, I thought that (and it certainly applies when orbiting the Sun for example) but on a hypothetical interstellar trip well outside the significant gravitational influence of stars, is it still falling?

[RB Will]

Odie said:

Beats the living st outa gravity using explosives

I like this best but I guess falling it is.

What if it were to be travelling across the galaxy under its own power rather than using other masses as a slingshot?

[KrazyIvan]

Depends, is it in a conveyor belt or not?

I am going with floating when outside of any external gravity field, so all forces acting on it are equal or 0.

And Falling when in orbit

....so erm both

[annodomini2]

ewenm said:

Yeah, I thought that (and it certainly applies when orbiting the Sun for example) but on a hypothetical interstellar trip well outside the significant gravitational influence of stars, is it still falling?

Yup, the sun orbits the galactic centre which is estimated to be between 25,000-28,000 light years away.

Gravitational influence decreases with the square of distance, but it's still there, the gravitational influence of the Sun extends for about 4.5 Billion light years as it propagates at the speed of light.

[deeen]

So does that mean a bullet is not flying? If you shoot upwards, it's not falling, to start with...

[ewenm]

deeen said:

So does that mean a bullet is not flying? If you shoot upwards, it's not falling, to start with...

It is falling - it is accelerating towards the ground as soon as you fire it upwards.

[ewenm]

annodomini2 said:

ewenm said:

Yeah, I thought that (and it certainly applies when orbiting the Sun for example) but on a hypothetical interstellar trip well outside the significant gravitational influence of stars, is it still falling?

Yup, the sun orbits the galactic centre which is estimated to be between 25,000-28,000 light years away.

Gravitational influence decreases with the square of distance, but it's still there, the gravitational influence of the Sun extends for about 4.5 Billion light years as it propagates at the speed of light.

Of course, so falling is the best description, orbiting can be useful and lets not get into "warping"

[Odie]

deeen said:

So does that mean a bullet is not flying? If you shoot upwards, it's not falling, to start with...

It has more force imparted on it than the force of gravity, with an explosion.

[Munter]

annodomini2 said:

Yup, the sun orbits the galactic centre which is estimated to be between 25,000-28,000 light years away.

Gravitational influence decreases with the square of distance, but it's still there, the gravitational influence of the Sun extends for about 4.5 Billion light years as it propagates at the speed of light.

I didn't ever think about gravity "propagating" and therefore having a distance at which it no longer affected other things. I just assumed it got weaker to the point that local conditions massively overwhelmed the effect of the star in the furthest reaches of the universe.

If we created a universe that consisted to just 2 atoms. And put them stationary 4.5 million light years apart. It would take 4.5 million years before they are attracted to each other?

[annodomini2]

They would each have to be travelling towards each other at a relative C for them to reach each other in 4.5m years.

1 lightyear is the distance travelled by something moving at the speed of light for 1 year.

[ewenm]

He said "attracted to" rather than "meet".

[Munter]

annodomini2 said:

They would each have to be travelling towards each other at a relative C for them to reach each other in 4.5m years.

1 lightyear is the distance travelled by something moving at the speed of light for 1 year.

Yes but if they pop into existence stationary, 4.5 million light years apart, and the effect of gravity spreads at the speed of light. It would be 4.5 million years before they start to accelerate towards each other?

The time it takes to collide being another thing I guess could be worked out. But wasn't what I was thinking of.