Build Our Own Star?

OK, so Cecil is pretty skeptical about insterstellar space travel. This planet’s sentient population, though, in a few billion years, will be needing to find new digs.

What if we chucked the whole ‘pack up and fly to a new star’ idea, and build our own damn star?

If we slammed a bunch of brown dwarves together, would some of that star-making magic happen? How many brown dwarves would we need to build a new star? Would we need a yellow star, or would a red suffice? What could we use to start attracting brown dwarves to where we need them? How far away would we have to keep the star while we were building it?

Is this whole idea more feasible or less feasible than insterstellar travel?

If we could move some brown dwarves from wherever they happen to be in order to put them together, it’d be easier to build a ship and go elsewhere.

Well, I guess I wasn’t clear - if we built the star, “we” wouldn’t actually have to go out and get them. Interstellar travel for a space ship isn’t so tough, it’s just taking the humans along that’s the problem.

I’m imagining we’d fling a Jupiter out there, or something, to slowly affect the path of a brown dwarf, so that in a few million years, it’d be where we want it.

I obviously haven’t thought through all the details, but let’s say it’s a solution that doesn’t require humans leaving the planet, or earth leaving its orbit, until the relatviely nearby star is ready and waiting.

Probably the best method would be to bundle a few dozen pairs of black dress slacks together and place them in space at the desired location of the new star.

If the rate of lint accumulation is anywhere close to the levels that I see at home, the new star would reach critical mass and combust in only a few thousand years.

I wouldn’t recommend using more than 3 dozen pairs, though. We don’t want a black hole on our hands.

Nothing like having a T Tauri flare star on our hands, which is what we’d get if we actually managed to pull off accumulating enough material to make a new star.

You do realize that the smallest brown dwarf is about 3,000 times the mass of Earth as a whole, and that’s insufficient for any nuclear fusion to occur, right? Anybody happen to know how many times the mass of the Earth the mass of the Sun is? That’s what you’re looking at moving.

Interstellar migration of a few billion people is simple by comparison. Just hollow out and fit to taste a few thousand asteroids, and set up stable ecologies inside them. Plus, of course, a power source for both interior power needs and motive power.

On the other hand, the Solar System has three components radiating internally generated energy – the Sun, Jupiter, and Saturn. The latter two produce only enough to raise them from cryogenically cold to extremely cold, but it’s better than nothing! (I forgot precise figures, but Jupiter-heated-only-by-insolation is 100 degrees Fahrenheit colder than its actual temperature, which is somewhere around -100 Celsius, all in round figures.) In 2010 Clarke had the Monoliths cause an implosion of Jupiter’s core sufficient to cause fusion to begin; whether this is theoretically possible is something I leave to the resident astrophysicists. (It’s certainly not technologically possible today!)

However, we do have an approximately five billion year period in which to refine our techniques for stellar creation, interstellar flight, etc. And probably sometime in that period the Solar System will approach another, younger G star closely enough that we could (with new technology, of course) cause Earth to move from a Solar orbit to an appropriate orbit around the younger star with sufficient speed to avoid total freeze-over.

i would rather shut the sun down before it burns out, then use its energy slowly by running thermonuclear reactors. should last pretty much forever since the fraction of sun’s energy that we get on earth is vanishingly small now and would be 100%.

now you just figure out how to do that :slight_smile:

This presumes there will be a sentient population on this planet in a few billion years. But sure, let’s run with the idea.

Brown dwarf stars vary in mass, not least because no one quite agrees on a clear definition for them. However, you need about a thousand Jupiter masses to make a star like the Sun, and brown dwarves range from about 10 to 80 Jupiter-masses.

So, you’d need somewhere between a dozen and a hundred brown dwarves smushed together to make a replica of the Sun — presuming that would even work. The Sun, like other stars, formed from a collapsing gas cloud, not the collision of large extant bodies. Seems to me offhand that the physics of such a collision might not allow hydrogen fusion to start. (Too high a temperature; too much hydrogen would escape?) But perhaps someone else can better answer that question.

You pretty much need a class G “yellow” (actually white) star, because life on Earth has evolved under the Sun’s spectrum. A low-mass star has both the wrong luminosity and wrong spectral distribution of light.

You can compensate for the lower luminosity by moving your planet (a hapless Earth?) to a smaller orbit, but then you’ll have tidal lock between the planet’s rotation and revolution. That certainly would make you unpopular back home, assuming there’s anyone still alive to complain. Moreover, the incorrect spectral distribution you can’t do anything about, without adding enough mass to the star to completely change its spectral class.

In other words, making it like the Sun.

We have no technology that could even begin to aspire to push stellar and quasi-stellar objects around like they were augies in a marble game. Sorry to be a wet blanket here.

Far less, I’m afraid. Far more feasible to find a newly born class-G star and then move everybody there. And then move everyone again when it burns out, and again when the third one burns out, and so on.

It’s a pain, I know, having to move every ten billion years like clockwork. No doubt some people will still have unpacked boxes lying around from the last move. But we all have to roll up our sleeves and do our part.

If we are able to even contemplate building a star by moving near-stellar , I can’t see why we would need to.
a) Clearly, it would be much easier to simply move the Earth to more a hospitable area than to move starstuff here. Take the moon along if we’ve grown attached to it, but it would probably be more cost effective to get a new one later.
b) Why would we need a star, anyway? It’s very wasteful, all that energy radiating away into space, only a tiny fraction of it being intercepted by the Earth. Build something smaller that shines a tight beam on just the Earth.
c) Skip it all… build something like Niven’s “Ringworld,” which if you think about it could have done nicely without the star in the center, provided one added suitable lighting and power sources.
d) The underlying problem was that it was too difficult to move people across stellar distances. This will be untrue long before we could do any of the above.

Also remember that eventually Earth is going to grow cold because our own radiactivity in the core and the heat generated therefrom will eventually run out. I have no idea how long that will take. But I think by the 3rd or 4th sun, we’d have to make a whole new earth.

Why not just make a bunch of Battlestar Galactica ships and tell them to find some lost colony of humans out there. Eventually they’ll give up and settle a nice planet. Or they’ll turn into Cylons and kill us all.

so nobody likes my idea of shutting down the sun and then mining it for hydrogen ?

Not until the canary stops coming back well-done.

OK, that’s useful information. Is that what you get whenever you put brown dwarves together, or just in a crude crash 'em together way?

Well, one point I should have raised in the beginning, that I did not, is that there are probably a whole bunch of brown dwarves within close proximity, relatively speaking, to our solar system - they’re a lot more abundant than true stars. So I was thinking it’d be smaller distances, and people wouldn’t need to go there personally - until the new star was ready, a few light months, or whatever was a safe distance, away.

Also, I’d like to point out that getting the first brown dwarf moving would be the toughie. If you aimed it right, then you could use it to start tugging on the other dwarves you want to collect. And I’m assuming you’ve got a several-million-year plan
in place - which is still waiting until the last minute in cosmological time.

Of course I do- it is part of the long term strategy for existing in our universe; every brown dwarf and every star will eventually have a colony of some sort if civilisation does not collapse before humanity reaches the stage where leaving the solar system is an option.

Many bright stars will need their mass decreased by star lifting in order to use the hydrogen and other elements more efficiently.
A protortion of the energy of the stars will be needed to propel ships outward to new territory; but most hydrogen will be best used in controlled reactions to power the colonies;
whether there will be any living beings in these colonies or simply electronic entities is open to debate.


SF worldbuilding at
http://www.orionsarm.com/main.html

The colliding brown dwarf scenario might come in useful a long way down the line, when there is little hydrogen left;
we will perhaps be able to gain energy from collisions between the burnt out cinders of stars (mostly cold white dwarfs or whatever takes their place after billions of years of stellar engineering).

I’m sorry if I didn’t understand something but I don’t see the reason here. Why would we need another star?

becasue in a few billion years the sun is going to swell to such a giant size that it engulfs the earth.

That would be a bad thing in case you are still confused.

From what I’ve been given to understand, whenever enough mass to form a star comes together (whether it be normal accretion in an interstellar cloud or the merger of two or more substellar masses), what results is a body that begins heating up, starts hydrogen fusion, and becomes a red star. Because “its stellar engine is just revving up,” it is subject to regular pulsations accompanied by flares. But, unlike Solar flares which increment the Sun’s luminosity by a fraction of a precent while active, these can be 10-50% increases in the baby star’s luminosity – not a healthy way to run a life-bearing solar system! These almost-new flare stars are called T Tauri stars after the prototype in Taurus.

On the main sequence, the brightest stars – O’s, B’s, and A’s – are very luminous, with too much ultraviolet, and extremely short-lived in the bargain. The lower half of the next range, F, the G range, and the upper few divisions of the orange K range, are suitable for supporting planets with terrestrial ecospheres. The remainder of K, along with the very common low-mass red M stars, are very long-lived but produce very limited light and heat, meaning a close-in ecosphere where any planet is probably tidally locked and hence unlikely to have life. (The sun is a G0 star, at the top of the G range.)

Suppose instead of creating a new star, we revive an old dying star…we start pumping in some hydrogen from a gas giant.

If our sun was on its last thousand years before supernova and we could siphon off hydrogen from Jupiter, Saturn, Uranus, and Neptune, how many more millenia/eons would that buy us?

Furthermore, lets suppose we have the ability to draw off the post-fusion byproducts (carbon, iron) that’ll eventually choke the sun…would that help?

Red dwarfs aren’t actually a problem. You just put a Jupiter close to the star, and then make your “planet” a moon of that gas giant. Lock to the planet, and you’ll still rotate relative to the star. The spectrum would be off, but that’s hardly insurmountable.

And Enola, given that the Sun is, as mentioned above, a thousand times more massive than Jupiter, I can’t see that it would make any difference to dump Jupiter in.

Well, I don’t think the last thousand years is the time to start talking about this. I think 500 million years is maybe time to get a plan started.

Pumping more hydrogen into the sun would help after we left the planet - the first problem is going to be that the earth gets way too hot as the sun increases in size (I don’t think the sun will actually engulf the earth - when sombody claimed that they forgot to take into account that the sun is constantly giving off mass, and will be much less massive at the time it grows).

For a while, we can live with a swelling sun by slowly increasing orbit (which is accomplished by buzzing the planet with an asteroid in a carefully planned orbit that gives us a slight tug with each pass).

I still think my idea might be a good one if it turns out that interstellar travel isn’t impossible, but just really, really sucky.

So we have the technology to go out to a new star, but would rather build one a few light months away.