May 7th, 2008
Things man will never do 1: Rebuild the Sun
There are certain themes that arise in Astronomy Cast comments and fanmail. Most of the themes are happy, good, warm fuzzies. There are also your typical cranks. There are also, in the humorous category, a regular stream of well-meaning, highly hopeful people saying my mind isn’t open enough who accuse me of not talking to the right experts.
I actually laughed loudly enough to scare the dog when I read the following earlier today from here:
Please! Get your facts straight, people!
Your original assumption is faulty, the Sun does not need to heat up and expand in a billion years, it will not “run out of fuel” in a billion years.The reason the Sun is predicted to heat up and expand in a billion years, is not lack of fuel, but the interference of the ash products, iron and silicon, with the internal fusion processes. There will still be 95 percent of the current amount of Hydrogen in the sun then, as there is now. Please talk to a knowledgeable Solar Physicist.
Removing those ash products so they will not interfere with the normal operation of the Sun, is merely an engineering problem.
Any person who uses a fireplace realizes that occasionally you need to remove the ash products.
Please talk to a knowledgeable Solar physicist before you go making simplistic unthinking fearmongering statements for the sake of entertainment. Yes, it is a danger. No, it is not an inevitability. Currently we don’t know how to fix it, but in 1910, we didn’t know how to make manned Moon landings, either. We know about the problem, we can work on the engineering solutions.
Let me say, it is not my habit to laugh out loud at comments. Nor is it my habit to share my dog scaring laughter publicly. This comment was posted publicly however, and I have to admit that the idea that we over hyped the eventual expansion of the Sun for the sake of entertainment is hilarious.
No, um, we weren’t fear mongering. Sorry.
So here’s the facts of physics. The Sun is a plasma gas. As it creates heavier elements, they fall to the center. Currently, in the center of the Sun there is a region that is of sufficient density and temperature that hydrogen is fusing into helium. The helium, weighing more than hydrogen, has no desire to leave the core. When this region of burning is completely filled with helium, burning will stop, the Sun will collapse a bit, and a shell of hydrogen will end up burning around the core (causing the Sun to expand back out).
Now, in the above comment the idea is put forward that we should be able to clear this “ash”, the helium, out of the way to keep the Sun on the main sequence burning hydrogen. Let’s just disregard the fact that you can’t exactly fly a spacecraft into the center of a star even in the Star Trek universe. Ignoring the problem of building something that will function under pressures and temperatures that turn everything into plasma, my question is, move the helium to where? This is like saying you’re going to swim to the 10ft deep bottom of a swimming pool (that is undergoing nuclear reactions), and pick up all the rocks some little kid threw in and just leave them 3 feet up from the bottom of the pool. Yes, you can pick them up and hold them there, but when you let go, they kind of fall straight back down to the bottom. Now, in general I would tend to carry the rocks up from the bottom and just set them on the side of the pool, but the Sun doesn’t exactly have an edge and it seems very silly to remove the helium all together. This helium is a non-trivial amount of mass, and the energy requirements to move it (F=ma, and W=Fd, even in the future) are HUGE. If you have this kind of energy and technology, wouldn’t it be easier to just move Earth? (Which after all weighs less then all that helium). And if you’re tired of Earth, if you have that much energy, you can probably grab a few asteroids or a small moon, hollow them out, and make them a colony vessel that can just go somewhere else altogether.
I do firmly believe their is a bright technological future of unimaginable wonder in front of us. I also believe in particle physics and know that things (like space craft) tend to melt in the centers of stars. So… I vote for taking Earth to Alpha Centauri.
If wormholes turn out to be anything more than a mathematical curiosity in some of the stranger corners of physics, it could be possible to drain excess helium out of the Sun by dropping a wormhole mouth into it. The engineering aspects of creating a very small wormhole, dropping one mouth into the center of the Sun, accelerating the other mouth to beyond solar escape velocity, and then expanding the wormhole it to a large enough size to have a meaningful effect on solar chemistry are left as an exercise for the implementer.
Yoinks Scoob. I always get amazed at the lengths that the human imagination can go and then claim that because we can imagine it, then it’s inevitable. Some things are wildly behind comprehension, even in a million years. Not to mention the basic misunderstanding of physics.
Good explanation Pam.
I think we should use the helium to float Earth to Alpha Centauri- maybe in a really big balloon.
Love the podcast. Keep up the good work.
The solution is simply using a high tech version of a chimney sweeper. Like the giant robot cleaning lady in the movie ’spaceballs’. It’s very doable..If i could just get my hands on one of those NASA charge cards i could get the R&D completed in no time. ( plus i need a replacement iPod )
Re: using a wormhole to shovel out the He: no need to accelerate the other end, the He shooting out under *extreme* pressure should do the job rather nicely.
In fact, we could use that as the rocket engine to move other things, like a habitat or small planet.
Of course, before we do that, we’ll make a similar wormhole bridge to move a bunch of Venus’ atmosphere to Mars.
Ah, planet-scale engineering. I look forward to it.
That was so funny [LOL]. I like your explanations.
No, no you’re wrong alternative scientific theories guy. You’re not even a good paranoid conspiracy theorist. We NEVER actually went to the moon. It was filmed on a Hollywood back lot, next to the set of “I dream of Jeannie”. Neil Armstrong is a Freemason, NASA is controlled by the Freemasons, therefore, we never actually got there. However, they actually did orbit the moon in “Apollo 13″, which starred Tom Hanks and Kevin Bacon. And if you do your research, then you can trace Neil Armstrong back to Kevin Bacon through his mother’s grandmother’s sides cousin twice removed…..
Invader ZIM has the solution! Mars is really a giant space ship. Zim was going to destroy the Earth by rolling Mars all over it, but he was stopped by his nemesis Dib! Dib realized that Mercury was also a giant space ship and used it to defeat Zim’s plan!
Since Mars will survive the solar holocaust, I say we hijack it and fly it to a new star! Bring blankets because the trip will get cold. Go to the bathrooom before we leave, I am not stopping along the way for bathroom breaks!
Hi Pamela, great post, very well explained.
I read about your blog in Physics World (super magazine), had to check it out.I like the way the log is aimed at a lay audience, can’t understand why so few physics blogs do this…
I’m encouraged to hear you’re not afraid to tackle the boundary between science and religion - I’ve been getting some stick from colleagues for reporting on a theology conference on my effort(www.coraifeartaigh.wordpress.com). To *hell* with it - I heard John Polkinghorne give an excellent talk at a conference last year and it really got me interested in the area (not that I entirely agree with him).
Have I been here before? the fields seems to remember me…Cormac
Apologies - no should be no www in the address I gave above (you can tell I’m new to this, any comments welcome)..Cormac
You silly astronomer, it’s “turtles all the way down”. *wink*
professor R:
Have I been here before? the fields seems to remember me…Cormac
That’s the funniest line of the day on so many levels..
I tried that once in class and almost got flunked.. Yet you pulled it off without a hitch..
ps. I’ll check your blog out
The solution is obvious.
We’ll have to move all the helium to Earth. We’ll all sound like the MGM Munchkins for the rest of our lives but we get a few more billion years for our planet. Seems like a decent trade off don’t you think?