The meaning of getting to Mars? Your view?

Hopefully by the time we need to make the trip we'll be capable of going fast enough to take advantage of time dilation. That should make the journey much more bearable.

Loosening our orbit to 1.15 astronomical units is enough to keep the Earth from being engulfed by the red giant. That can be achieved by sending asteroids whizzing by the Earth (sending them around Jupiter first so the gravity assist gets them moving really fast). When each one buzzes by the Earth, it will tug our position a little bit. If we calculate the trajectory correctly, that tug will pull our orbit outward.

Maybe it won't be worth the effort since the sun will die after the red giant phase. But it's doable.

What is much more worth the effort is keeping the Earth habitable over the next 5.4 billion years before the red giant phase begins.

The growing heat of the sun is going to render Earth uninhabitable in only 500 million years. Mirrors should be able to counter that for a few billion years, and maybe even for the entire 5.4 billion year period before the red giant phase begins.

Shielding Earth from the heat of the red giant phase would definitely be technically demanding.

But difficult doesn't mean impossible. Think of it as an inverse of a Dyson Swarm. Instead of a bunch of orbiting structures intercepting most of the light output of a star, it would be a bunch of orbiting structures intercepting most of the light that would otherwise fall on a planet.

The biggest issue will be "will it be worth the effort" since at that point the sun will soon dim forever. We'd be doing quite a lot just to prolong the life of the Earth by a small amount.

Shielding the Earth during the 5.4 billion years before the red giant phase, on the other hand, is much more worth the effort. And it will also be much less technically demanding.

There is no reason for us to have to flee the Earth before the red giant phase begins.

I could not agree less.

Why not protect the earth for the next 5 billion years, then leave shortly before the red giant phase begins?

Because in just a billion alone the temperature of the Sun will increase its output by 10% and the Oceans will boil...

The existence of a danger to the planet isn't a reason for not protecting the planet from that danger.



Not if we protect the earth and prevent that excess sunlight from reaching the planet.

The problem is that you have to first grasp that Earth is a mechanical system that has an established feed of solar energy, which it has evolved in tandem with for as long as it has existed.

You also have to realize that you can't just put a bunch of solar shields in orbit around Earth and have them stay there permanently and not break down due to bombardment by xrays, cosmic rays, dust/debris, and other exposure to energy that's they're not shielded from the way they would be if they were closer to sea level.

Chlorophyll has evolved to reflect energy abundantly. It does so to retard/slow the rate at which energy is absorbed by leaves/trunk/branches/soil because everything has to stay hydrated to survive.

Trees and plants also absorb latent heat from their surroundings and warmer cells transport nutrients and grow at a faster rate. So trees/plants are designed/evolved to use the latent waste heat of the environment to grow leaves/canopies that reflect sunlight.

So when you talk about building and launching solar shields around the planet, you are talking about huge quantities of energy that have to be somehow harvested/mined from Earth's energy budget and then used to make and deploy a huge number of artificial solar shields that would need to cover an area greater than that of the Earth at sea level (which is already enormous).

And you can't just build and deploy these shields once and forget about them; you'd have to maintain them the same as you'd maintain a roof or solar array that breaks down and needs repairs and replacement that costs lots of effort, energy, and materials.

I think you should put some effort into thinking about how a forest canopy, whether it's a rain forest or a deciduous forest or a northern boreal forest or an established agricultural orchard maintains itself by growing/dropping seeds, which automatically/naturally sprout and grow to replace their aging parents.

You can't engineer a system that automatically builds and deploys orbital solar shields by absorbing some of the solar energy they are reflecting, so that the net effect of systemic entropy doesn't affect Earth's energy budget.

For argument's sake, let's say you could design such a system and then just 'seed' an automated solar-shield-factory that flies itself around the solar system using only solar power, gathers materials it needs to reproduce itself, and then brings the solar shields back to Earth orbit so that the overall solar shield maintains itself indefinitely without polluting the Earth with unmanageable debris OR depleting the Earth of energy/resources needed to maintain various aspects of the system.

I find that about as likely as the prospect of building a fleet of self-driving cars and automated infrastructure machines that reproduce themselves while maintaining a sustainable infrastructure that keeps humans in harmony with restored/natural climate.

I'm not saying they both aren't interesting prospects to theorize and critically plan/assess; but I think you have to proceed from the restriction that you don't allot Earth's energy to achieving them; because the moment you invent a project/process that taps into Earth's energy budget, you're initiating a pattern of dependency that will be difficult if not impossible to reform over time.

Whenever an industrial/economic pattern is launched and established, eventual reform prospects get thwarted and/or suppressed in the interest of protecting the economic interests that would be interrupted by reforms.

Humans struggle to preserve status quo and avert change, so it doesn't make sense to begin projects that are unsustainable with the intent of reforming them later to become sustainable. New projects should already be sustainable when they are initiated, and otherwise it should be 'back to the drawing board' to make them permanently sustainable and non-harmful from the start.

Trouble is, as Ive said, SCience Fiction often is just as full of **** as its not.Perhaps More. My concern is that the sun, as it grows in intensity and size, will gradually grow out of its condition as a "point source of just heat energy" .Thats gonna be difficult to overcome. While Im really not trying to dump on your sci-fi option, I must demand that, as someone whose got an invested interest in my own genomes continuity, I say we should be futzing with several, maybe 10 or more concepts.
Secondly, If you look up the reactions involved (there are four, involving H to H2 and One H2 to He3and He4, and He4 to energy and Li and Be). As each GROWS in intensity, it doesnt just exude heat, It gives off increasing ionizing radiation (think gamma ). Any shield system must be able to address the ionizing radiation. I think these shield system may hav a really short product life. Thats why a real intensive proof- of- concept, followed by study is needed and it needs to be shared with the world for critique

However, It is good that we are actually addressing this aspect of our solar systems life and beginning to think about our responsibilities to our descendents .

We could maybe do a better job in engineering for a "quality of life" to future generations by considering actual terraforming of an outer planet's satellite. We could maybe get a few billion yers out of thi concept , all before our ring of planets goes on a "brown out"

Since Jupiter is essentially a mini sun, there was a short sci-fi story about stoking jupiter into becoming a H1/He2 /proton furnace, (like out nascent sun was ). and the only problem woul be the shape of the orbital "neighborhood" wed be enjoying (unless we could move the Jovian satellite out of reach)

It too sounds extreme, but, like anything, I expect that future generations will be invested with much more advanced technologies than we have now. (Like sub-light travel perhaps)

Actually, the concept of a Dyson ring actually seems to be a bit easier to engineer. Wed accept the conditions but we would "point our living space away from the growing ball" All itd be required to do is to gradually away from the sun at each critical point in a rings rotation and orbit around th earth. Just a sloppy guess but maybe wed be living on a Dyson Space Station ring.
Water would be a challenge, itd be busy boiling off on earth

Best summary of near term climate mitigation I’ve seen is Isaac Arthur on YouTube a day or so ago. Once you stop laughing at the sound of Elmer Fudd narrating a scientifically accurate script, you realize he knows what’s what.

Some of the solutions might involve H bombs.

can you find that one? I was wondering whether we could even "Gravity lock" something like a bunch of deflection gizmos or "Dyson rings" so they wouldnt turn into space junk whcich could leave us a critical "hole in our safety net" if something bumps into just one.

I can’t get this damn device to capture urls. He’s pretty well known so googling his name will get you there.

Web browsing on PS4 sucks.

Oh my gosh you have a PS4 and you are a gamer!!! I would never ever think you would have one...prejudice and mea culpa!

We could build a ring world in this star system. Even so, the lease expires with the star in about eight billion years.

But why not make an effort to protect the Earth for the next five to six billion years, and then leave when the red giant phase starts?

Keep in mind that mirrors can defect light that comes from multiple directions at once. So long as the light bounces in a direction away from the Earth, it is successfully deflected.

Also, I keep getting the feeling that everyone is missing my main point. It's probably not worth it to go to all this effort when the sun will be about to extinguish its fire at that point no matter what we do. It's like racking up ten million dollars in medical bills to extend the life of a 98 year old man by a couple weeks.

My main point is that we should make an effort to keep Earth habitable in the period BEFORE the sun starts expanding.

I didn't see a link to a video about climate migration, but I did see a bunch of other interesting videos from him that I am now downloading.

I'll do a more in-depth search a bit later, and will post the link if I think I've found the video that you are referring to.

"mirrors wont capture any more light than thesurface is able to acquire. ALso, youve missed the point that, as the sun expands it becomes more like a solar flare and generates waay more gamma radiation which will NOT reflect in mirrors at all.
The sci fi writers keep missing that point totally.

OK, but what about the 5.4 billion years before the sun starts expanding?