How to increase gravity...???

[xelasnave]

This is not a case of only ask a question if you know the answer by the way...so I expect to make Mars suitable for us..er some of us;) we need a few things and I have become somewhat focused on the need for an atmosphere which cant be that hard to make but keeping it would mean we would need more gravity to hold on to it I imagine...wanting to help I started thinking about how we could increase gravity..add more mass no doubt but that may not be necessary if we could increase rotational speed..but would that do it?.. intuitively I am torn between gravity increasing on the one hand or stuff being thrown off into space on the other...my limited understanding of GR does not equip me to work out the math but does anyone have any ideas?

No doubt Elron has it worked out ..does he I wonder.

alex

[Hodur]

Lack of a magnetosphere is the driving issue

[ChrisD]

It's believed that Mars lost the majority of its atmosphere not because of a lower gravity compared to Earth, but because Mars lacks a magnetic field.

The Sun emits a continuous stream of charged particles called the solar wind.
Earths molten iron core produces a magnetic field that mostly deflects the solar wind, but some leak through at the Earths poles cause the aurora. Without this magnetic field the solar wind would slowly strip the atmosphere from a planet.

Mars' iron core cooled fast, likely because of its small size, and its magnetic field shut down around 3 billion years ago. Before the core cooled it's believed that Mars had an atmospheric pressure similar to Earth. The NASA MAVEN probe determined that Mars is currently losing atmosphere at at rate of 6kg per minute.

Interestingly, the solution to the Mars atmosphere problem may come from Venus. Venus has an atmosphere but no core generated magnetic field. ESA Venus Express indicated that a magnetic field was being generated by an interaction between the solar wind and the Venus' ionosphere. Maybe we could make this happen on Mars.

Chris

[xelasnave]

Interesting observations but we are yet to address the question I hid in my post.
Will increasing rotational speed increase gravity?

alex

[Startrek]

My thoughts on ways to increase gravity on Mars would be possibly a catastrophic event like another celestial body ( moon ) inadvertently colliding with Mars on a specific angle of trajectory at immense velocity thus forcing the planet to rotate faster and at the same time increasing the relative mass.
An atmosphere ( similar to Earths ) could possibly be created by a such an event as Mars has the necessary ingredients within its terrestrial make up. Also due to the event a more favourable orbit might be achieved closer to the Sun which might have positive outcomes for gravitational stability and atmospheric environments.
This process could take millions if not billions of years. Unfortunately our dinky little planet Earth doesn’t have time to wait for that to happen, that’s probably why Elon wants to habitat Mars over the next 1000 years using self contained habitat type environments in his future Martian City’s

Just my initial thoughts …..

[ChrisD]

Put simply, no, increasing the rotation rate of a planet will not increase the gravity.

Chris.

[glend]

A number of solutions have been put forward to create an artificial magnetosphere.

[mura_gadi]

By the time we can eat out a planet and replace the core with iron and correct a spin at that sort of scale...

Things like the "ring world" will be common.

[glend]

https://www.researchgate.net/publication/355198821_How_to_create_an_artifici al_magnetosphere_for_Mars

[JohnF]

But Mars shows us aurora. That requires a magnetic field does,not it ?? Iron core rotating planet gives a magnetic field doesn't it ??

Am not a Physisist. so not ex[pert. but that is what I thought.

[ChrisD]

Hmm, I should have said global magnetic field.

For a full explanation see:

"We now know how aurora might form on mars without a global magnetic field"
https://www.sciencealert.com/we-now-know-how-aurora-might-form-on-mars-without-a-global-magnetic-field