We Don’t Know Everything Yet
Posted by hyperpat on November 17, 2006
Looks like yet another accomplishment for the Hubble Telescope. Analysis of some of its images of very distant supernovae is giving credence to the idea of dark energy, and that it’s been around a long time, exerting its repulsive force between objects for that entire period. Now dark energy, along with dark matter, is a pretty strange beast. The only way we can even infer its existence is the observable effect it has on the amount of gravitational force between objects. Apparently it doesn’t interact with anything else that’s ‘normal’. And yet the supposition is that over 70% of the universe is actually composed of this stuff.
One of the competing theories to explain the observed accelerating expansion of the universe is that the gravitational force is somehow changing over time. I don’t think the current observations have knocked out this hypothesis yet. And, given our poor understanding of just what gravity is, why it exists, how it propagates through ’empty’ space, and how it fits in with the strong, weak, and electromagnetic forces, (grand unified field theories have so far not been totally successful), this hypothesis appeals to me rather than the invoking of an otherwise unobservable ‘dark energy’. Of course, I’m only an engineer, not an astrophysicist, so what do I know? But at the very least, it appears that there is some method of producing a negative gravitational force. Which means that all those SF stories with anti-gravity thingies running around may not be that far off-base.
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Peter said
Hi, I was sure I would find a tribute to Jack Williamson here this past week. Did you enjoy his works? I always loved ‘The Humanoids’ and ‘The Humanoid Touch’, and if the truth be know…I still enjoy the various Legion of Space stories (especially Giles Habbibula as a character). As a ‘Patrone’ of Sc-fi on Amazon, I would be interested to read your comments.
Thanks and Happy Thanksgiving
Pete from Doylestown, PA
hyperpat said
Never did read much of Williamson’s stuff. His Legion never grabbed me (just too 30ish for my tastes), and the few collaborations he did with Fred Pohl struck me as poor.
Nimish Batra said
Pat… http://news.bbc.co.uk/2/hi/uk_news/6158855.stm
I think it was due for him to say it. We knew he was thinking it for a long time.
What about his suggestion of matter/antimatter propulsion drives. How do we store or control antimatter? *eep*
hyperpat said
I certainly agree that we need to establish our presence on some other planet than Earth. Too many potential disasters are just waiting to happen out there. I don’t agree that we necessarily have to do so in another star system, though. Mars isn’t great for humans right now, but it looks like it would be possible to terraform it at reasonable cost, effort, and time (depending on what your point of view about ‘reasonable’ is). The only disaster that would wipe out both Mars and Earth at the same time would be the sun going nova (which reminds me of Heinlein’s short story “The Year of the Jackpot” – but the real probability of this happening before the next four billion years have gone by is next to nil).
And Hawking apparently either dismisses or didn’t consider the idea of multi-generation star ships. Given hundreds of years to reach other star systems, all kinds of other star-ship drive mechanisms become available, from solar sails to standard nuclear engines.
As far as storing anti-matter, the only real possibility is a magnetic bottle, and then only for those particles that have a charge.
Nimish Batra said
I think Hawking dismisses multi-generation starships simply because there are many MANY holes in our technology for now.
The size of such crafts would mean that lift off is impossible off the Earth’s surface. They’d have to be assembled in orbit or on the moon. We don’t have the tech for that. Heck, the first major in-orbit project – The ISS – is proving so damn tough!
There must be other things, but at 7 am, they escape me. Awful how my early mornings are beset by a lack of alertness. Stupid college routines.
Plus if I’m not mistaken, the only antimatter we’ve successfully generated is anti-gamma-particles. I don’t remember exactly, but I think they’ve been around for 20 years or so.
Mars is a bit too cold, a bit too sandy and there’s too much magnetism everywhere for our tech to keep working for sufficient periods. Notice that we can’t even get the rovers working properly. And even satellites have failed. Whether it’s incompetence or it’s a mysterious agent, either way, if we can’t get a passive probe to Mars, human beings are a totally diffferent matter. It’ll take us a full 200 years, and without political will, maybe more, just to get started with this idea.
hyperpat said
Any method of getting to the stars is quite a ways off, and just about all methods will require a large amount of in-space assembly, regardless of what type of propulsion system is used. Which just means that we need to get started now, before all our resources run out, or any of 14 different major disaster scenarios occurs.
The first anti-matter particle to be observed was the positron (the anti-electron) in 1932. There’s no such thing as an anti-gamma particle, rather gamma rays are most of the end product of the annihilation of a particle and its anti-mirror. You’re correct, however, that it wasn’t until the mid-nineties that we managed to created entire atoms composed of anti-particles.
Yes, Mars is cold, with way too little atmosphere right now. But it doesn’t have a magnetic field to speak of (in fact it’s be theorized that that’s why its atmosphere is so thin, as there’s no magnetic field to deflect the solar wind from stripping the atmosphere away). Yes, we’ve had some of the probes to that planet fail, but there are also several successful ones (the current score is six successful orbital insertions, two failures). Two hundred years is probably just to get started on terraforming this world, the actual process could easily take a thousand years. One of the best books I’ve read that uses this idea as a main premise is Kim Stanley Robinson’s Red, Blue, and Green Mars set.
And interstellar exploration and terraforming Mars are not mutually exclusive goals. Probably a lot of what is learned from getting to and trying to change our neighbor planet would help in the design and building of any star-traveling vehicle.