# Mars as Second Earth

• A
I have been reading about Mars and planetary rotation and gravity. It seems to me Mars was in Earth's rotation at one time. Most likely it's first period. I want it back. I don't believe it's an impossible task. People exercise drilling and fracking and sending out satalites. How impossible is slowing down Mars orbit so it'll fall into ours using these methods? We only need to slow it about 4 light minutes.

Reposted under astrology

Drakkith
Staff Emeritus
I have been reading about Mars and planetary rotation and gravity. It seems to me Mars was in Earth's rotation at one time. Most likely it's first period.

It is extremely unlikely that Mars was ever in the same orbit as Earth.

I want it back. I don't believe it's an impossible task. People exercise drilling and fracking and sending out satalites. How impossible is slowing down Mars orbit so it'll fall into ours using these methods? We only need to slow it about 4 light minutes.

The amount of energy needed to move a planet into another orbit is staggeringly huge. More than the total sum we've ever used here on Earth. It would take about 1.8x1032 J of energy to move Mars into Earth's orbit. By comparison, humanity used about 5.67x1020 J of energy in 2014. That a difference of about 12 orders of magnitude. At that rate of energy use, it would take about 100 times the current age of the universe to use 1032 joules of energy.

tobyr65
Drakkith
Staff Emeritus
Reposted under astrology

We don't have an Astrology forum.

CalcNerd, tobyr65 and 1oldman2
The only things powerful enough to move planets, is another planet.

Also, once it was in our orbit, what would you do with it? You can't have two planets in the same orbit.

tobyr65
Also, once it was in our orbit, what would you do with it? You can't have two planets in the same orbit.
Um, you can. Earth has less than 1/27 the mass of Sun.
Would you want Mars to be a Trojan or an Achaean?

Um, you can. Earth has less than 1/27 the mass of Sun.
Would you want Mars to be a Trojan or an Achaean?
Dragging an asteroid and having a planet there seem to me like they're different sorts of things. Mars has millions of times the mass of a trojan asteroid. I'm quite certain the gravitational attraction between the two objects would cause them to drift towards each other and go into chaotic orbits.

tobyr65
Chronos
Gold Member
Moving mars, however implausible it may seem, would not remedy its habitability issues. Moving it closer to the sun would exacerbate the effects of the solar wind making it even more difficult to teraform. Without a significant magnetic shield it would be defenseless and giving it one would make relocating mars appear trivial by comparison. Like space travel, planetary engineering is immensely energy intensive. It's not just a matter of resources, we can't even imagine what might provide a sufficient energy source, much less how to harness it.

CalcNerd, tobyr65 and 1oldman2
Janus
Staff Emeritus
Gold Member
Dragging an asteroid and having a planet there seem to me like they're different sorts of things. Mars has millions of times the mass of a trojan asteroid. I'm quite certain the gravitational attraction between the two objects would cause them to drift towards each other and go into chaotic orbits.
One of the major factors determining the stability of a Trojan object is the mass ration between the planet and the Sun. Since the Sun is some 330,000 times more massive than the Earth, this allows a bit of leeway for the mass of the Trojan object. To text the idea as to whether Mars would be stable at as an Earth Trojan object, a ran a grav-sim simulation. Since perturbations from other bodies can effect the stability I added a Jupiter to the Simulation. after 15,000 simulator years, Mars still showed no signs of changing its relative position with respect to the Earth.

nikkkom and tobyr65
The only things powerful enough to move planets, is another planet.

Also, once it was in our orbit, what would you do with it? You can't have two planets in the same orbit.
Dragging an asteroid and having a planet there seem to me like they're different sorts of things. Mars has millions of times the mass of a trojan asteroid. I'm quite certain the gravitational attraction between the two objects would cause them to drift towards each other and go into chaotic orbits.[/QUOT

newjerseyrunner, Thank you for your response. No. You are right. Another massive satellite to earth would drag on Earth to do all sorts of wrong things. And there is no way to ensure Mars could orbit at same speed as Earth peacefully at the 180 of Earth. I think making Earth 2 (E2) would require moving Mars closer to the sun though. What I would do with it is let it self regulate ( terraform ) for many years. And then populate it. See other replies coming to below responses. Isn't it fun speculating tho![/QUOTE]

It is extremely unlikely that Mars was ever in the same orbit as Earth.

It is unlikely that Mars has been in its current position since its formation. Maybe its magnet field fell after it was knocked out of its original position. Maybe its was in the same orbit but it was tramatically 're-positioned' during its polar flip, thus not being able to recover the magnetic dynamo? Perhaps the moving of Mars would place enough stress to the core it already has to reform the magnetic shield?

Also I just found this so my uneducated opinion is being validated out there. :) https://www.newscientist.com/article/dn20160-two-planets-found-sharing-one-orbit/

The amount of energy needed to move a planet into another orbit is staggeringly huge. More than the total sum we've ever used here on Earth. It would take about 1.8x1032 J of energy to move Mars into Earth's orbit. By comparison, humanity used about 5.67x1020 J of energy in 2014. That a difference of about 12 orders of magnitude. At that rate of energy use, it would take about 100 times the current age of the universe to use 1032 joules of energy.[/QUOTE]

We would need 'smart guy' to figure out how to use the solar system's (ss) elements to act as a pulley. I know we are no where near to harnessing the ss energy much less how to direct that energy. But I think to terraform a dying planet is less sci-fi than traveling to a ready made planet.

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Dragging an asteroid and having a planet there seem to me like they're different sorts of things. Mars has millions of times the mass of a trojan asteroid. I'm quite certain the gravitational attraction between the two objects would cause them to drift towards each other and go into chaotic orbits.

Also I just found this: https://www.newscientist.com/article/dn20160-two-planets-found-sharing-one-orbit/

It is extremely unlikely that Mars was ever in the same orbit as Earth.

https://www.newscientist.com/article/dn20160-two-planets-found-sharing-one-orbit/

The amount of energy needed to move a planet into another orbit is staggeringly huge. More than the total sum we've ever used here on Earth. It would take about 1.8x1032 J of energy to move Mars into Earth's orbit. By comparison, humanity used about 5.67x1020 J of energy in 2014. That a difference of about 12 orders of magnitude. At that rate of energy use, it would take about 100 times the current age of the universe to use 1032 joules of energy.

Dragging an asteroid and having a planet there seem to me like they're different sorts of things. Mars has millions of times the mass of a trojan asteroid. I'm quite certain the gravitational attraction between the two objects would cause them to drift towards each other and go into chaotic orbits.

I
Um, you can. Earth has less than 1/27 the mass of Sun.
Would you want Mars to be a Trojan or an Achaean?

I can't answer that yet. I get the Trojan asteroid reference but I haven't read up on Achaean yet. I'll try to reply tomorrow....that was easy reading. Achaean. Two planets in one orbit forming at the same rate yet one with a slight difference in velocity so that in 500 million years or so the smaller less protected planet got ever so gently pushed away.

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One of the major factors determining the stability of a Trojan object is the mass ration between the planet and the Sun. Since the Sun is some 330,000 times more massive than the Earth, this allows a bit of leeway for the mass of the Trojan object.

To text the idea as to whether Mars would be stable at as an Earth Trojan object, a ran a grav-sim simulation.

It is crazy to me you can sim that information. Love it. Do you have access to predicted bodies coming into contact with Mars in a way that might push it our way? Seriously, I agree the amount of force needed would be to great for humanity to harness in the next few thousand years. My only realistic hope would be a large body to zoom through the solar system and graze Mars. And I do not believe mars would have to become a Trojan in Earth's orbit.. Once I believe it likely it was Achaean with us but considering the physical nature of Mars currently... I think it would need to orbit slightly closer to the Sun than we are. C/2013 A1 appears to be to far off to have a wake that could move it. Also if the asteroid is moving outward instead of inward that's no help

Since perturbations from other bodies can effect the stability I added a Jupiter to the Simulation. after 15,000 simulator years, Mars still showed no signs of changing its relative position with respect to the Earth.

Drakkith
Staff Emeritus
To text the idea as to whether Mars would be stable at as an Earth Trojan object, a ran a grav-sim simulation. Since perturbations from other bodies can effect the stability I added a Jupiter to the Simulation. after 15,000 simulator years, Mars still showed no signs of changing its relative position with respect to the Earth.

I loaded up my Universe Sandbox (find it on Steam), loaded up the Solar System, and put Mars a little ways behind Earth and in a very similar orbit. After 1100 years there's no sign of any obvious drift.

It is unlikely that Mars has been in its current position since its formation.

Indeed. But that is not what I claimed.

Also, tobyr, it would be very, very helpful if you could read up on PF's reply and quote system. You're mangling it right now and it makes your posts hard to read.

The "Reply" button will quote the post, pasting it into the reply box immediately. The "+Quote" button will add the post to a que, and you can quote several posts and then scroll down and click on "Insert Quotes" at the bottom left of the reply box to insert all the quoted posts into the reply box. (Don't put your own text in between the the quote tags, which are the "quote" and "/quote" you see at the beginning and end of each quoted post, except they have brackets instead of quotations around the words)

In saying perhaps Mars had just been re-positioned I was trying to be politic. I still believe it developed along side Earth. I do not know physics but I know co incidences rarely are. Did you read the link? Cool huh?

I'll read the PF's reply and quote system as soon as I locate it and before I reply to anything else.

Drakkith
Staff Emeritus
I'll look around when I get the chance and see if I can find the info. I know it's around here somewhere.

Mars sits firmly in the trend of density geting lower with higher distance from the sun, suggesting it is where it was. The result is the same when you analyze some isotope ratios. Moving planets around would cause crazy climate variations unlike anything deductible from surface properties. There is a great debate whether Mars was ever really much warmer in the past, or it just had much denser atmosphere and warm-based glaciers feeding most of the fluvial activity.
Despite what you may think or simulate the Lagrange points are not stable for any mass of the 'Trojan' object. There is a very popular hypothesis that once there was a Mars-sized planet near the Lagrange point on Earth's orbit.... And thats why we now have the Moon. Do you want to crash Mars into 'Earth-1'? Very bad idea.

And did you read the update on KOI-730 system? (BTW it is now known as Kepler-223) It is much more plausible there is a chain of resonant orbits instead of coorbital planets.

tobyr65
I have been reading about Mars and planetary rotation and gravity. It seems to me Mars was in Earth's rotation at one time. Most likely it's first period. I want it back. I don't believe it's an impossible task. People exercise drilling and fracking and sending out satalites. How impossible is slowing down Mars orbit so it'll fall into ours using these methods? We only need to slow it about 4 light minutes.
It has been suggested that Jupiter formed ~3.5 AU from the sun, then migrated inward towards the sun during the formation of the early solar system, to a distance of approximately 1.5 AU (where Mars sits today). When Jupiter and Saturn achieved an orbital resonance of 2:3, both Jupiter and Saturn began migrating outward until they reached their current orbits.

This means that Jupiter would not only have crossed the region of the asteroid belt, twice, but it also would have deprived Mars of much of its building material. It is because of Jupiter's suggested migration inward that Mars may be as small (0.107 M) as it is. While I could find no specific reference of Mars moving in its orbit, if it is being suggested that Jupiter moved as close as 1.5 AU away from the sun before moving back out to 5.2 AU, then Mars would have had to either be closer than it is currently, or formed from the material left over after Jupiter began its migration outward.

Sources:
Compositional evolution during rocky protoplanet accretion - The Astrophysical Journal, Volume 813, Number 1, October 29, 2015 (arXiv free reprint)
Jupiter’s decisive role in the inner Solar System’s early evolution - Proceedings of the National Academy of Sciences, Volume 112, Number 14, February 11, 2015, DOI: 10.1073/pnas.1423252112 (arXiv free reprint)
http://www.nature.com/nature/journal/v475/n7355/full/nature10201.html - Nature 475, July 14, 2011, DOI: 10.1038/nature10201https://arxiv.org/ct?url=http%3A%2F%2Fdx.doi.org%2F10%252E1038%2Fnature10201&v=821657cc[/URL]([URL='https://arxiv.org/abs/1201.5177']arXiv free reprint[/URL])[/SIZE]

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tobyr65
sophiecentaur
Gold Member
The amount of energy needed to move a planet into another orbit is staggeringly huge. More than the total sum we've ever used here on Earth. It would take about 1.8x1032 J of energy to move Mars into Earth's orbit. By comparison, humanity used about 5.67x1020 J of energy in 2014. That a difference of about 12 orders of magnitude. At that rate of energy use, it would take about 100 times the current age of the universe to use 1032 joules of energy.
Looks to me as if those figures signify 'end of' this conversation. If we had a fraction of that amount of energy, we could take a heater and air con over to Mars, harvest the water from several comets / asteroids or whatever and get Mars into a condition suitable for living on as long as we could want. Why bother to bring Mars closer to us?

we could take a heater and air con over to Mars, harvest the water from several comets / asteroids or whatever and get Mars into a condition suitable for living on as long as we could want. Why bother to bring Mars closer to us?

To make it a bit warmer? I would be okay with that :D
BTW, you can "harvest the water from several comets" and "bring Mars closer to us" at once. Find a suitable comet and nudge its orbit so that it impacts Mars' leading hemisphere while Mars is at the perihelion. This "only" requires that you can move comets slightly.

Whacking Mars with comets or, preferably, rocky asteroids won't shift the orbit significantly unless they're big enough to leave a hemispheric crater. Sadly that would barely affect the orbit, but it would blow off a tangential chunk of the already-thin atmosphere, cause a LOT of property damage and potentially waste much permafrost. { "White Gold, Homesteads' Key..." } Also, it would probably scatter Martian meteorites across the inner Solar System, creating a unwelcome 'Hazard to Navigation'.

IIRC, if you did get Mars into Earth orbit, it had better be at 'Leading' or 'Trailing' Trojan position, as the 180º / 'Far Side of the Sun' scenario beloved of sloppy Sci~Fi writers is meta-stable. Between Venus' and Jupiter's influence, it would become 'incoming' in geological time.

Could you trade it for the Moon ? Well, it would have to be further out to keep month and tides the same. { 'Exercise for Student' stuff ;-) }

Much, much easier, after an initial 'under-ground base' phase, to roof over some of Valles Marineris' side canyons, then extend them to meet...

sophiecentaur
Gold Member
I find it hard to think of a scenario where it would be worth using an extra planet. By the time humans could do that sort of thing, I am sure they would have 'dealt with' the population problem (humanely) and the reason for moving home would have to be some horrific predicted event in the Solar System. That would require moving to another Star.
Anyone ever watch Space 1999?. Now that really was an interesting scenario. Taking your own planet with you.

sophiecentaur
Gold Member
Find a suitable comet and nudge its orbit so that it impacts Mars' leading hemisphere while Mars is at the perihelion.
I guess you must have been watching the Championship Snooker on UK TV.

Looks to me as if those figures signify 'end of' this conversation. If we had a fraction of that amount of energy,
How much energy was needed to move Jupiter?

Whacking Mars with comets or, preferably, rocky asteroids won't shift the orbit significantly unless they're big enough to leave a hemispheric crater. Sadly that would barely affect the orbit, but it would blow off a tangential chunk of the already-thin atmosphere, cause a LOT of property damage and potentially waste much permafrost. { "White Gold, Homesteads' Key..." } Also, it would probably scatter Martian meteorites across the inner Solar System, creating a unwelcome 'Hazard to Navigation'.

You assume that people who can move a comet are too stupid to vaporize it shortly before impacting Mars. :D

Drakkith
Staff Emeritus