In the far distant future, as we all know, the sun runs out of fuel,expands to a red giant and incinerates the earth. We need to plan NOW to prevent this catastrophe. My plan would be to move the outer planets, with the exception of jupiter into the sun. I realise such an undertaking would be impossible for the forseeable future, but in a few billion years who knows?
Assuming the sun had a few thousand years of fuel left and we gently dropped the gas giants into it, how much additional time would this give the sun? (They’re pretty big).
Here’s another suggestion. What if we built some type of giant scoop/storage machine that flew into interstellar space scooping up hydrogen and then when full, set a course for the sun and crashed into it, adding tons of additional hydrogen. Imagine thousands of them, scooping up hydrogen for thousands of years.
Some might say it would be easier for such an advanced race to just pack up and move to a nice new solar system. I agree, but think Earth is special and should be preserved if possible. Aside from the formidable(to put it mildly) engineering problems involved in saving the sun, could it conceivably be done? Approximately how much hydrogen is used each day to power the sun? From what i understand its not all that much (relatively speaking) which is why the sun can burn for billions of years.
Been out in the Sun again without your hat and sun screen, eh?
Been out in the Sun without your hat and sun screen again, eh?
Looks like I got too much sun with the double post!
IANA physicist, nor have I been out in the sun without a hat yet today, but it seems to me that if you dropped a few gas giants into the middle of an already-guttering sun, that it would drop the temperature, same as when you’re barbequing, and you throw another handful of charcoal briquettes onto a pile that ain’t doing too well to begin with, and it promptly puts the kibosh on the whole proposition and you have to go inside and cook the burgers on the stove.
I dont think so. The fusion reactions take place due to the intense pressure at the center at the center of the sun. The earth isn’t heated in the same way as a person standing in front of a fire. The space in between is a vaccuum. You just gotta keep that nuclear reaction going…
Solar system data here.
If you add together Jupiter, Saturn, Uranus, and Neptune, you’ll see that their combined mass is only 0.13% that of the sun, which is probably not enough to make much of a difference. But, you’re probably thinking, the sun would be much more of a lightweight in the future, but I’d argue that by then the Earth would be roasted to an uninhabitable environment already. I’m neither an astronomer nor an environmental scientist, though, so the pros may disagree with me.
It is not just the total available mass, it is the total available Hydrogen that matters. So, much of what is in the mass of the gas giants would be things other than Hydrogen, and some of it might well be heavier elements that would have a negative net effect on the duration of the sun’s natural cycle of life.
And, the gaseous envelopes of the planets would have to get down into the depths of the sun, as well, to have any prolonged effect on the hydrogen fusion rate. Most of it would be evaporated, and ionized, and driven away by the heat and solar wind, as the planets moved into range. That effect would be strongest on the hydrogen, and then on Helium, etc, as the atomic weight goes up, precisely the opposite sort you want.
That same ablative effect will work on any mass of Hydrogen you bring to the sun. The stellar engine only starts after the accretion of Hydrogen is sufficient to begin the process of fusion, and lasts only if the mass of the star is sufficient to maintain the pressure of Hydrogen against the explosive energy of a billion hydrogen bombs a second. Nothing you could do to bring that much Hydrogen to the sun would fail to destroy the Earth.
Tris
I suspect this would have the opposite effect you want.
The fusion occurs in the Sun’s core, where pressure and temperature are high enough. Outside this region, fusion doesn’t occur. Now, the region outside the core is still loaded with hydrogen, even after the core itself runs out of fuel. It’s like having a gas can in your car trunk; your main tank can still run out. You would have to somehow get the fuel into the core of the star, and that’s not really possible.
Worse, by adding mass to the outer layers, you are basically adding to the compression in the Sun’s core. The fusion reactions in the core are extremely sensitive to pressure and temperature, so adding mass will actually increase the fusion rate, bringing the inevitable that much closer.
To make the Sun last longer, you’d want to remove mass. I’m not sure how you could do that. 
Yes, getting rid of solar mass will allow us to keep the sun around for a much longer time. Lower mass stars burn happily at a slower pace for a longer time. Higher mass stars have shorter lifetimes and burnout in a flashier, red-giant fashion.
In any case, you’re fighting a losing battle. No energy source lasts forever and the sun is no exception. Even if you engineer a way to avoid Red-Giant baking of our Earth, you’d have to keep moving Terra Firma in closer and closer to the sun to get the an equivalent amount of flux (energy per unit time per unit area) to the Earth’s surface to keep it habitable as the star slowly dies. Eventually it wouldn’t matter how close you got, there just wouldn’t be enough energy.
All good things must come to an end. The Sun and Earth being no exception.
I wouldn’t worry it. I’d say there’s a pretty good chance human beings won’t be around to deal with the issue when the time comes. Better to worry about things that directly effect the survival of humanity in the short term rather than looking at billions of years down the road.
To wit, look out for them rogue asteroid and comet planet-killers!
…I’d venture to say that if human beings (Or whatever had evolved from us) were still around by the time the sun starts running out of fuel, we’d have the technological ability to rectify the situation. If we even cared, that is.