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Posts Tagged ‘Astronomy’

Dawn probe reaches Ceres orbit!

Or as I like to call it, a Ceres circuit. Ba-dum-bum!

But Ceres-ly, folks…

This morning, at about 1239 GMT (or 7:39 AM where I am), the Dawn space probe successfully entered orbit around the dwarf planet Ceres. The NASA press release is here:

Nasa Spacecraft Becomes First to Orbit a Dwarf Planet

Unfortunately, Dawn is currently on the dark side of Ceres, and is orbiting slowly enough that it won’t come around to the light side until mid-April. So the best we get for a photo at the moment is this one from March 1:

Ceres March 1 2015

Image Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

 

This is historic as the first orbit of a dwarf planet (the New Horizons probe later this year will only fly by Pluto, I believe) and the first time a probe has orbited two different bodies. And it’s significant to me since it means Dawn has now visited both of the Main Belt protoplanets featured in Only Superhuman, first Vesta back in 2011 and now Ceres. With Vesta, the timing was right to let me incorporate a bit of what Dawn discovered into the novel during the revision process — but with Ceres I just have to hope nothing contradicts what I wrote. My main description of Ceres in the book was as follows:

The sunlit side of the dwarf planet was a dusty gray, except for the bright glints where craters or mining operations had exposed fresh ice beneath.

So far, so good, I’d say, given the other photo we got recently:

Ceres bright spots

Image Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

Scientists are speculating that those bright spots might be exposed ice, or maybe salt. Although you know what they kinda look like to me?

The on switch.

More news as it develops…

Thinking about other universes (or, the trouble with infinities)

December 8, 2011 8 comments

I’ve been mulling over another subject that was suggested by the recent NOVA miniseries “The Fabric of the Cosmos,” hosted by physicist Brian Greene based on his book of the same name.  I felt some of the ideas it put across were too fanciful, putting sensationalism over plausibility or clarity, and one of them was the topic of its concluding episode, “Universe or Multiverse?”

The premise of that episode was that, if the Big Bang happened as the result of localized symmetry-breaking in an ever-inflating realm of spacetime, then our universe could be just one “bubble” in a perpetually expanding cosmic foam, with other universes being separate “bubbles” with their own distinct physics and conditions, forever out of reach because the space (how many dimensions?) between us and them is forever expanding.  Now, that’s okay as far as it goes.  It’s a somewhat plausible, if untestable, notion given what we currently know.  But what Greene chose to focus on was a rather outre ramification of this: the idea that if the multiverse is infinite, if there’s an infinite number of other universes alongside ours, then probability demands that some of them will be exact duplicates of our universe, just happening by random chance to have the exact same combination of particles and thus producing the same galaxies, stars, planets, species, inviduals, etc. — kinda like how the famous infinite number of monkeys banging on an infinite number of typewriters will inevitably produce all great literature by chance.  Thus, so the claim went, there could be other universes out there that are essentially parallels to our own with duplicates of ourselves, except maybe for some minor variations.  (Or maybe universes where duplicate Earths and humans exist in different galaxies, or where a duplicate Milky Way coexists with a different configuration of galaxies, or all of the above.)

Note that this is entirely different from the concept of parallel timelines, the usual way of generating alternate Earths in science fiction.  Parallel timelines aren’t separate universes, despite the erroneous tendency of SF to use the terms interchangeably.  They’re coexisting quantum states of our own universe.  The idea is that just as a single particle can exist in two or more quantum states at the same time, so can the entire universe.  These alternate histories would branch off from a common origin, and thus it’s perfectly reasonable that they’d have their own Earths and human beings and the same individuals, at least if they diverged after those individuals were born.  And there’s at least the remote possibility of communication or travel between them if nonlinear quantum mechanics could exist.  What we’re talking about here is something else altogether, literal other universes that just happen by random chance to duplicate ours because it’s inevitable if there’s an infinite number of universes.  While parallel timelines would be facets of the same physical universe we occupy, and would thus essentially be overlapping each other in the same place, these duplicate universes would be unreachably far away, except maybe by some kind of FTL or wormhole technology if such a thing could ever exist.  And they might predate or postdate our own universe by billions of years.

But I think it was a flawed conceit to dwell on that aspect of the multiverse idea, and I have my problems with the reasoning employed.  For one thing, it’s purely an ad hoc assumption that the multiverse is infinite rather than finite.  If it’s finite, then there’s no guarantee that there would be other universes that exactly duplicate ours.  Certainly there could be ones with compatible physical laws, with their own stars and galaxies and planets and life forms, but odds are they’d be different planets, different species, different individuals.  No duplicate Earth, no duplicate Lincoln or Kennedy or Jet Li.

And if the multiverse is infinite, then sure, you could argue that with an infinite number of tries, it’s inevitable that our universe would be exactly duplicated somewhere.  But the flip side to that argument is that if there’s an infinite number of universes, then the odds that any given universe would duplicate ours would be n divided by infinity, or effectively zero.  In practical terms, if we found a way to visit other universes via wormholes or something, then we could search for an infinite amount of time before finding one that had its own Earth and human race and history duplicating ours except for having more goatees or whatever.  Thus, by any realistic standard, such duplicates would be effectively nonexistent. (This is the problem with infinity as a concept in science — it tends to lead to absurdities and singularities.  Physicists generally try to avoid infinities.)  So while that result (the existence of duplicate universes) might be a logically sound consequence of the premise of an infinite multiverse, it’s also a trivial result, one that has no practical meaning and can’t be proven or falsified.  So it’s not science, just sophistry.  It’s angels dancing on the head of a pin.  And that makes it a waste of time to focus on in a program that’s supposed to be about science.

Besides, it’s boring.  The show presented us with the prospect that there could be an infinite number of possible forms for universes to take, whole other sets of physical laws, an unlimited range of possibilities… and all they wanted to talk about was duplicates of the world we already know?  What a staggering failure of imagination — or what a staggering triumph of self-absorption.  I would’ve been far more interested in hearing about the endless variety of universes that weren’t just like ours.  Why not dazzle the viewers with some discussion about what physics would be like in a universe with more than three spatial dimensions?  Or one with a higher or lower speed of light?  That would’ve been so much cooler and more enlightening than the silly, dumbed-down examples they gave, like Earth with a ring around it or Brian Greene with four arms.

I suppose the one appeal of the infinite-monkeys premise is metafictional: You can use it to argue that if every remotely possible combination or interaction of particles is inevitable, then every fictional universe really happens somewhere.  So, for instance, I could claim that my various fictional universes — my default/Only Superhuman universe, the Hub universe, the “No Dominion” universe, whatever else I might eventually get published — all coexist in the greater multiverse, and their different physical rules, different principles of FTL and whatever, could be explained by subtle variations in the laws of physics of their distinct universes (and yet somehow don’t prevent the fundamental interactions, dark energy, and so forth from having the exact same values so that stars and planets and life can form the same way).  And it’s handy for fans who want to believe that, say, a crossover between Star Trek and Transformers, or Star Wars and Firefly, or whatever might be possible despite the huge differences in those universes’ histories and physics.  But I’m not sure I find it desirable.  To me, if there’s some planet in some unreachably distant universe that exactly duplicates Earth’s evolution and history, and has a duplicate of myself who’s writing this post at this equivalent point in his Earth’s orbit (which might be billions of years in the past or future relative to my “now,” if such a thing could even be meaningfully measured), I wouldn’t really think of him as me, or his Earth as being my Earth.  So it wouldn’t really feel to me that those other fictional universes connected to my world’s history, and that would make them less meaningful.

Or would it?  I mean, just going in, I know these fictional universes don’t have the same physical laws as our universe, that the specific characters or alien races or whatever that exist in them don’t exist in our world.  So I know going in that they’re already separate realities from my own.  Their versions of Earth and its history may correspond almost exactly to ours, yet they’re still separate entities.  So maybe it’s no worse to think of my various written worlds (blog name drop!) as coexisting realms in an infinite multiverse than it is to think of them simply as independent fictional constructs.

And sure, sometimes I think it would be nice to have some sort of grand unified theory linking my universes together.  I already tend to think of “No Dominion” as being in a parallel quantum timeline of my Default universe, because it has no visible discrepancies in physics or cosmology and has a lot of similar technological and social developments; it’s just that some technologies develop decades too early to be compatible with my published or soon-to-be-published Default-universe fiction.  That won’t work for something like the Hub, though, since it has distinct differences in physical law.  And yeah, I admit I’ve tried to think of a way to fit my universes together into a unified multiverse, at least in passing.  I suppose the “infinite monkeys” idea could give me a means to do that.

But I don’t think I find it appealing, because it just multiplies the variables to such an insane degree.  If these universes are just infinitely separated samples of an infinitely expanding metacosmos, then that doesn’t really unify them in any way, does it?  They’re so far apart, so mutually unreachable, that the “connection” doesn’t really count as a connection at all.  (After all, given the underlying physical premise, there’s no realistic chance of any kind of wormhole link or inter-universe crossover anyway.)  It’s a trivial and useless result fictionally for the same reasons it is physically.  And if they’re specks in an infinite sea of universes, it makes them all feel kind of irrelevant anyway.  So why even bother?  It’s simpler just to treat them as distinct fictional constructs and not bother trying to unify them.  Besides, even if I know intellectually that the humanity and Earth and Milky Way of my fictional universes aren’t the same as my own, it’s more satisfying to pretend they are, to construct a satisfying illusion for the readers that they’re reading about an outgrowth of our own reality, than to pretend that they’re some totally separate duplicates in universes unreachably distant from ours.  No point going out of my way to create a premise that alienates me and my audience from the universes they’re reading about.  Granted, judging from some conversations I’ve had in the past, there are some people out there who wouldn’t have a problem with that.  But it doesn’t really work for me.

Red dwarfs have wider habitable zones than we thought?

From Centauri Dreams:

Widening the Red Dwarf Habitable Zone

A new paper has revised our estimates of how wide the habitable zone would be around a red dwarf star.  This comes from taking into account the difference in spectrum between a red dwarf and a Sunlike star.  Compared to the Sun, red dwarfs give off a higher percentage of their EM radiation in longer wavelengths like red and infrared, wavelengths that aren’t reflected as much by snow and ice as shorter wavelengths are.  So while in our system, a planet covered in snow and ice would reflect a lot of heat back into space and thus reinforce its own freezing (runaway glaciation), in a red-dwarf system it would retain a higher percentage of the star’s heat and could stay unfrozen at a larger proportional distance than we’d thought.  This could make red-dwarf habitable zones 10-30 percent wider than we thought, and increase the potential number of habitable planets around them.  Sure, those HZs are pretty narrow to begin with, but red dwarfs constitute maybe 70-80 percent of the galaxy’s stars, so it adds up.

Be sure to read the comments.  There’s a lot of interesting discussion about other factors that would go into habitability around a red dwarf.  It’s a lively and ever-evolving subject in astrophysics today.

Categories: Science Tags: ,

Dawn probe reaches Vesta orbit!

Yesterday, July 16, 2011, NASA’s Dawn space probe entered orbit around the asteroid (or more properly, protoplanet) Vesta, the second-most massive object in the Main Asteroid Belt.  This is a mission I’ve following with interest, and I made a previous post about it back in April.  But now I can reveal why I’m particularly interested in this mission — because my upcoming novel Only Superhuman is set in the Asteroid Belt, and much of its action takes place on habitats around Vesta (or around Ceres, which Dawn will visit in 2015).  The novel mentions little enough about Vesta itself that I hope I won’t have to do any rewrites as a result of Dawn‘s findings, but I’m going to keep my eye on this just in case, and who knows — maybe I’ll get to write more about Vesta in a sequel.

Here’s the NASA press release:

http://dawn.jpl.nasa.gov/feature_stories/spacecraft_enters_orbit.asp

And here’s the clearest photo of Vesta to date, taken on July 9:

 Dawn photograph of Vesta

So… we now have direct experience of Vesta.  I guess that means we aren’t Vestal virgins anymore! 😀

I’m too disorganized

Since Star Trek DTI is such a blank slate of a concept, I’m seeing it as an opportunity to explore some ideas I haven’t had a chance to do anything with before.  For instance, there’s a certain established Trek species that I’ve long wanted to do some serious worldbuilding for.  They haven’t been featured much onscreen, and what little has been done with them in prose either plays up a certain attribute of their species to the point of caricature or avoids it to the point that they’re rendered generic.  And a lot of the behind-the-scenes worldbuilding that was developed for them has never really been built on in prose.  Now I finally have a chance to feature a major character of that species and get my ideas about them on paper.

One of those ideas I came up with was identifying their fictional home star with a real star.  The way I did this was, I think, rather obsessive but rather clever.  The book Star Trek Star Charts by Geoffrey Mandel, which is generally treated as authoritative by the novelists, includes that star but doesn’t identify it with a real star.  So what I did was to use the Celestia space simulator, which lets you see the known stars in 3D from any position in space, and find an angle that matched the positions of the major stars as featured in the STSC maps (i.e. which is more or less looking directly “down” on the plane of the galaxy).  Then I highlighted various stars which were roughly in the same position, as seen from that angle, as the fictional star in question was in STSC.  With them highlighted, I changed my angle to see where they were along the Z axis (the axis perpendicular to the galactic plane) and thus how far they were from Earth and other major stars.  Based on position, spectral type, and so on, I settled on one of them as the most reasonable candidate for this species’ home system.

And I wrote it down.

Somewhere.

The thing is, I did this sometime last year, as part of development for a pitch that didn’t go anywhere, or maybe for a subplot I considered while developing a novel but decided not to use.  When I decided to use this species for DTI, I opened the file containing that unused pitch and I found a reference to the species’ home star having periodic x-ray flares, a property of the real star I had picked for them.  That reminded me of the work I’d done to select that star.  But there was nothing in that proposal that named the star.  And when I looked through all my other possibly relevant notes files on my computer, I couldn’t find it anywhere.

So I thought maybe I’d done it as part of a technical discussion on the TrekBBS.  So I searched there for posts by “Christopher” that contained the name of the planet in question, and found nothing.

So I was stumped.  But I had a memory of writing something down somewhere.  Maybe it was on a piece of paper somewhere, but my desk, table, etc. are very cluttered and it’s hard to find any stray piece of paper.

Then I remembered this 8 1/2 x 11 spiral notebook I use for various things.  I looked through it, but there was nothing.  Finally I remembered my 3 x 5 notepads.  I have a couple of these which I’ve used alternately for various things, one of which was completely filled up a while ago.  I haven’t used them much lately, so I guess I kind of forgot about them.  Anyway, I spotted the filled-up one under the mess on my table, I looked through it, and after just a few pages I finally found what I’d written down about the star I’d chosen.  Yay!

This time, I hastened to transcribe the information from the notepad into my story notes file for DTI.  That way I won’t lose it again (unless something disastrous happens to both my laptop and my thumb drive).

It goes to show that a writer shouldn’t throw anything away.  You never know when an old idea or bit of research might come in handy.  But it also shows the importance of a decent filing system so you can find stuff again.  That’s the part I need to work on.

A still more glorious dawn awaits…

December 28, 2009 1 comment

Apparently this video is quite a popular meme lately, and after coming across two separate, unrelated references to it in one morning, I gave in and watched it.  And I’m glad I did.  It’s probably the only good thing that’s ever resulted from AutoTune.

Yay, my first embedded video!

And the first reference to it was in today’s xkcd strip, also worth calling attention to:

http://xkcd.com/681/

Categories: Science Tags: ,

Ocean planet found!

December 16, 2009 4 comments

In 2003, Marc Kuchner and Alain Léger independently proposed the existence of a new hypothetical class of planet, which Léger dubbed “Ocean planets.”  These are worlds that consist primarily of water — not just balls of rock covered in a thin veneer of water like Earth, but worlds that consist substantially or primarily of water, with small cores of metal and rock deep beneath a thick mantle of exotic high-pressure ices with a liquid ocean somewhere around 100 kilometers deep.  These worlds could have thick water-vapor atmospheres, and if hot enough could have the ocean and atmosphere combined into a single layer of supercritical water, an intermediate stage between water and steam.

In 2008, I used a Léger-type ocean planet as the featured location in my novel Star Trek Titan: Over a Torrent Sea, which was published in March of this year.  As far as I know, it’s the first published work of science fiction to use this concept.  (There have been water worlds in SF before, but not specifically like this.)  The details of the ocean planet “Droplet” are discussed in my annotations for the novel.

Now, just 9 months after OaTS came out, astronomers have announced the discovery of what’s probably a real ocean planet!  The New York Times reports:

Astronomers said Wednesday that they had discovered a planet composed mostly of water.

You would not want to live there. In addition to the heat — 400 degrees Fahrenheit on the ocean surface — the planet is probably cloaked in a crushingly dank and dark fog of superheated steam and other gases. But its discovery has encouraged a growing feeling among astronomers that they are on the verge of a breakthrough and getting closer to finding a planet something could live on.

“This probably is not habitable, but it didn’t miss the habitable zone by that much,” said David Charbonneau of the Harvard-Smithsonian Center for Astrophysics, who led the team that discovered the new planet and will reports its findings on Thursday in the journal Nature.

Only 2.7 times the size of Earth and 6.6 times as massive, the new planet takes 38 hours to circle a dim red star, GJ 1214, in the constellation Ophiuchus — about 40 light-years from here. It is one of the lightest and smallest so-called extrasolar planets yet found, part of a growing class that are less than 10 times the mass of the Earth.

It’s significantly bigger than Droplet, which was 1.7 Earth radii and 2.7 Earth masses.  GJ 1214b reportedly has a density about a third of Earth’s.  According to Centauri Dreams, that probably makes it about 3/4 water and other volatiles, 1/4 rock.  Droplet was about half and half by mass (and 55% Earth’s density), which was because that was the model used in the paper I based my calculations on, but Ganymede, Callisto, and Titan all have about the same ratio, so it wasn’t entirely arbitrary.  Centauri Dreams also says it appears to have a very dense atmosphere about 200 km deep, and adds:

We should be able to learn more about this atmosphere, for GJ 1214b is close enough to Earth that the Hubble telescope should be able to characterize its atmosphere.

Isn’t that awesome?  A nearby planet with water and atmosphere.  Not habitable, alas, but it brings us so much closer.  If this planet is out there, then habitable, water-bearing terrestrial worlds must be as well.  And the thought of the Hubble telescope doing planetary science on an extrasolar planet is monumentally cool.

And from my perspective as an author, it’s awesome to have a concept I used in a novel verified by a real discovery just months later.  All too often, we SF authors get our concepts debunked by new discoveries instead.

Although of course it’s Léger, Kuchner, and David Charbonneau’s team who deserve the real props.