Anonymous
Anonymous asked in Science & MathematicsAstronomy & Space · 8 months ago

# Should we classify planets by weight?

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• 8 months ago

Weight my friend is a concept easily construed as Mass

On Earth we have Mass

We also have an extra force added on to that, called Gravity

Gravity plus Mass equals weight

I am 87 Kg

In the ISS I would still have the same Mass but without Gravity

I would be in Orbit, a state of falling, but at a Velocity of Orbit that Keeps me at the same Altitude constantly

In order to Change any of that we need external force

To slow up or speed up

Less Velocity will lower our Altitude, more, the opposite

It is Newton's Third Law of Motion at work

Anyway I diverge

In orbit, bodies are considered weightless

So Planets have Mass

They would only have weight if you could add gravity to weightless objects

So it doesn't make sense

• 8 months ago

There is no "weight" in zero gravity. Only mass.

• Tom S
Lv 7
8 months ago

Planets by definition need to be in orbit of a star, objects in orbit are in a state of free-fall, so weightless.  Planets are weightless.

• 8 months ago

You do know that mass and weight aren't the same thing, right ?

• 8 months ago

The weight of a planet is not its mass but a function of its diameter and mass.  It would be entirely feasible for a "puffy planet" orbiting close to its star to have the same weight as a rocky planet further out.  They would have very little else in common.

• Anonymous
8 months ago

Sure. Why not. Break out the scale.

• 8 months ago

No, we should not, since the mass

of a planet already gives us a guesstimate of its weight.

• Lôn
Lv 7
8 months ago

No, by mass. .

• ?
Lv 7
8 months ago

And how exactly do we weigh them?

• 8 months ago

We more or less already do .  That's why Pluto was a planet, then wasn't (because it was considered too small), and then was again (because people were attached to it and complained).  There are thousands, maybe millions, of objects orbiting our Sun, we just call the large ones "planets".