We may be within a generation of sending probes on flyby missions to other stars, high-energy jets from several distant galaxies all point in the same direction, and we're learning more about hot super-earths.That sort of thing fascinates me, your experience may vary.
Meanwhile, SETI researchers will be checking out red dwarfs: which may be more promising places to look for neighbors than we thought.
- Breakthrough Initiatives' Starshot Project: Sailing to the Stars
- That's Odd: Aligned Galaxy Jets
- Too Hot for Air
- Still Searching for Neighbors
"...Only Two Possibilities...."
"Thar's only two possibilities: Thar is life out there in the universe which is smarter than we are, or we're the most intelligent life in the universe. Either way, it's a mighty sobering thought."I've quoted Kelly's Porky Pine before. It's among the more clear-headed things I've seen written about the possibility that we may have neighbors in this universe. (July 26, 2015; November 7, 2014)
(Porky Pine, in Walt Kelly's Pogo; via Wikiquote)
In my considered opinion, there's life elsewhere in the universe: or not. I'd be astounded if there isn't, but right now we don't know.
As I've said before, 'is there life in the universe' isn't quite a new question.
Back in the 13th century, some European scholars had insisted that Earth had to be the only world like ours: because Aristotle said so. That's when the Church stepped in: reminding folks that God's God, and Aristotle's not. (July 31, 2015; June 27, 2014; February 23, 2014)
As it turns out, there are more worlds: some orbiting our star, plus a growing list of planets around other stars.
Aristotle has had a profound influence on Western thought, but he was wrong about our standing on the only world. I've mentioned Anaximander before: but not Democritus. They both thought there could be, and probably were, many worlds. (August 7, 2015)
As it turns out, they were right.
A recent news item involved SETI: Search for Extraterrestrial Intelligence. Maybe you've read why God's decisions don't upset or offend me.
If you have, feel free to skip down to Breakthrough Initiatives' Starshot Project: Sailing to the Stars, which doesn't involve SETI; Still Searching for Neighbors, which does; go for a walk; take a coffee break; whatever.
Order, Beauty, and Opportunities
Still with me? Thanks!Briefly —
I think that the universe operates according to logical, knowable, physical laws. As a Catholic, I must believe that. (Catechism of the Catholic Church, 299)
I must also believe that this universe is a place of order and beauty, and can learn something about God by studying God's creation: and that studying the universe is okay. We can, using reason, see God's work in the universe. (Catechism, 32, 35-36, 301, 303-306, 311, 1704)
We're told that scientific discoveries are opportunities for greater admiration of God's greatness. (Catechism, 283)
I certainly don't have a problem with that.
1. Breakthrough Initiatives' Starshot Project: Sailing to the Stars
(From Christian Darkin/Science Photo Library, via BBC News, used w/o permission.)
("This generic artist's concept shows how a solar sail might work"
(BBC News))
"Hawking backs interstellar travel project"I'm not sure what Hawking meant by "if we are to survive as a species...." He might have meant that we'd die if we don't travel to the stars: or that we'll certainly reach the stars if we survive. Either way, I think he's (almost) right.
Pallab Ghosh, BBC News (April 12, 2016)
"Stephen Hawking is backing a project to send tiny spacecraft to another star system within a generation.
"They would travel trillions of miles; far further than any previous craft.
"A $100m (£70m) research programme to develop the computer chip-sized 'starships' was launched by the billionaire Yuri Milner, supported by Facebook founder Mark Zuckerberg.
"Interstellar travel has long been a dream for many, but significant technological hurdles remain.
"But Prof Hawking told BBC News that fantasy could be realised sooner than we might think.
" 'If we are to survive as a species we must ultimately spread out to the stars,' he said...."
In the first case, if we stop trying to find out what's 'out there,' we'll have lost something very basic in our nature. I'll get back to that, later in this post.
In the second case, if we somehow manage to become extinct before reaching the stars — I really do not think that will happen. That's not blind optimism, and I've talked about that before. (December 24, 2015; October 25, 2015)
My attitude about Hawking's statements may be the sort of thing that happens when remarks by a theoretical physicist and cosmologist get nitpicked by a writer and artist. I talked about Hawking's support of a SETI project last year. (July 24, 2015)
Breakthrough Initiative's Starshot is "...aiming to demonstrate proof of concept for light-propelled nanocrafts. These could fly at 20 percent of light speed and capture images of possible planets and other scientific data in our nearest star system, Alpha Centauri, just over 20 years after their launch...." (News, Breakthrough Initiatives)
Starshot: This Just Might Work
Their version of Robert L. Forward's fictional beam-powered propulsion is a bit beyond today's tech: but not by much.I talked about more-than-a-bit-beyond-today's tech like beamed-core antimatter rocket engine and Forward's gigawatt laser array, week before last. (March 25, 2016)
Current 'light sail' technology, like NanoSail-D — that's a picture of it, unfurled in an Earthside laboratory — might have to be tweaked, but it's been flight-tested.
We may — eventually — build ships with thousand-kilometer-wide sails, pushed by light from massive laser banks, focused through 10-kilometer-wide lenses, as described in Forward's Rocheworld.
Or someone may have worked the bugs out of Alcubierre warp field1 generators by then: leaving the construction of light-sail ships to hobbyists of a later era.
Or we may discover that there's something fundamentally wrong with the math of both approaches: and find another way to travel between stars.
What jumps out at me from Breakthrough Initiatives' Starshot is their proposal of an Earth-based laser array using adaptive optics to focus the beam for comparatively rapid acceleration while the tiny ships are still relatively nearby.
That would eliminate the need to keep a beam focused over 'astronomical' distances.
I'm pretty sure at least some of the small probes would still be working after their three-decade trip to Alpha Centauri.
Voyager 1 and Voyager 2, launched in 1977, are still sending back data: 39 years into their missions.
Just how the Starshot probes would transmit signals back to Earth is — a good question. One approach, I suppose, would be to design them along the lines of Rubenstein's kilobots, so they could assemble themselves into a high-gain antenna when they arrived. (August 22, 2014)
Make that before they arrive. Starshot would be a flyby mission: zipping through the Alpha Centauri system at about 20% speed of light. That's fast enough to make the trip from Earth to our sun in a skosh under 42 minutes.
My guess is that the first interstellar mission, whatever propulsion tech we use, will be a flyby. That's what we've done before, sending probes to other planets. (November 13, 2015: October 30, 2015)
I'm also quite sure that we'll want probes that can slow down and take a look around after they arrive.
Background:
- Breakthrough Initiatives
- Wikipedia
2. That's Odd: Aligned Galaxy Jets
(From Prof Russ Taylor, via Royal Astronomical Society, used w/o permission.)
("An image of the deep radio map covering the ELAIS-N1 region, with aligned galaxy jets. The image on the left has white circles around the aligned galaxies; the image on the right is without the circles."
(Royal Astronomical Society))
"Astronomers in South Africa discover mysterious alignment of black holes"
News & Press, Royal Astronomical Society (April 12, 2016)
"Deep radio imaging by researchers in the University of Cape Town and University of the Western Cape, in South Africa, has revealed that supermassive black holes in a region of the distant universe are all spinning out radio jets in the same direction – most likely a result of primordial mass fluctuations in the early universe. The astronomers publish their results in a new paper in Monthly Notices of the Royal Astronomical Society.
"The new result is the discovery – for the first time – of an alignment of the jets of galaxies over a large volume of space, a finding made possible by a three-year deep radio imaging survey of the radio waves coming from a region called ELAIS-N1 using the Giant Metrewave Radio Telescope (GMRT) in India.
"The jets are produced by the supermassive black holes at the centres of these galaxies, and the only way for this alignment to exist is if supermassive black holes are all spinning in the same direction, says Prof Andrew Russ Taylor, joint UWC/UCT SKA Chair, Director of the recently-launched Inter-University Institute for Data Intensive Astronomy, and principal author of the Monthly Notices study.
" 'Since these black holes don't know about each other, or have any way of exchanging information or influencing each other directly over such vast scales, this spin alignment must have occurred during the formation of the galaxies in the early universe,' he notes.
"This implies that there is a coherent spin in the structure of this volume of space that was formed from the primordial mass fluctuations that seeded the creation of the large-scale structure of the universe...."
We've been learning quite a bit about the "large-scale structure of the universe" lately.The more up-to-date textbooks mentioned "island universes" when I was in high school. These days they're called galaxies, astronomers have been mapping galactic clusters and superclusters, which form walls and filaments of superclusters.
The universe we're in is huge and almost unimaginably ancient: which gives some folks conniptions. I don't mind a bit, and that's another topic. (September 26, 2014; July 15, 2014)
We've been studying 'light' — microwave frequencies, actually — from the edge of the observable universe, some 46,000,000,000 light years away 'now.' (June 14, 2015)
Those light quanta have been heading our way since this universe cooled down enough to be transparent, some 380,000 years after the Big Bang.
The Big Bang was only 13,798,000,000 years ago, give or take 37,000,000. Light — radiation of any sort that we know of — travels at the speed of light. But the edge of the observable universe is about 46,000,000,000 light years away because this universe is still expanding.
Oddly enough, that expansion is speeding up, and that's yet another topic. (April 17, 2015)
That gets me back to what the Inter-University Institute for Data Intensive Astronomy's Taylor said about "...primordial mass fluctuations that seeded the creation of the large-scale structure of the universe...."
Sort of.
Black Holes and the Universe
We've been learning that big galaxies generally have really big black holes in the middle. Stuff falling toward those black holes forms an accretion disk, sort of a scaled-up version of what forms around new(ish) stars. (November 14, 2014)That accretion disk spins — like pretty much everything else in this universe, it's a physics thing. Stuff in some accretion disks spins really fast: close to the speed of light.
When that happens, jets of stuff shoot out, parallel to the disk's spin axis. Scientists are still figuring out exactly how that works.
Pierre-Simon Laplace figured that the escape velocity for very massive stars might be greater than the speed of light, John Michell wrote about "dark stars" in 1783.
Karl Schwarzschild worked out the math for what we call the Schwarzschild radius in 1915, David Finkelstein and Charles W. Misner noticed a topological defect in the gravitational metric — that was in 1958.
Don't bother trying to remember all that: there will not be a test on this, not being a teacher any more has advantages, and that's yet again another topic.
Where was I? Primordial mass fluctuations, folks with names like Schwarzschild and Finkelstein, Quantum mechanics. Right.
I've talked about quantum gears and philosophy before: briefly. (September 26, 2014)The point is that stuff that became those galaxies used to be a lot closer than it is now. That's (probably) why their supermassive black holes spin on pretty much the same axis.
More than you probably need to know about:
- "Alignments of Radio Galaxies in Deep Radio Imaging of
ELAIS N1"
A. R. Taylor, P. Jagannathan; Monthly Notices of the Royal Astronomical Society, Oxford University Press (Received March 7, 2016 (in original form December 20, 2015); Accepted March 7, 2016) - Wikipedia
3. Too Hot for Air
(From Peter Devine, via BBC News, used w/o permission.)
"Planets stripped bare by host stars"What's "hot" and what's not depends on context. A pop tune may be "hot," metaphorically speaking, a summer day here in Minnesota can be "hot," literally, compared to our winter weather; and we've been finding quite a few metaphorically and literally "hot" exoplanets.
BBC News (April 11, 2016)
"Astronomers have confirmed the existence of planets that have had their atmospheres stripped away by their host stars.
"Planets with atmospheres that orbit too close to their host stars are bombarded by a torrent of high-energy radiation.
"The gaseous outer layers of these worlds are then stripped away, according to the international team of scientists.
"Their work appears in the journal Nature Communications...."
I've talked about 55 Cancri e and HAT-P-11b before. (February 19, 2016; October 3, 2014)
Scientists had good reason to think that at least some planets orbiting very close to their stars might be more massive than Earth, but with no atmosphere.
Now it looks like at least some of those theories are a pretty good match with reality. That will help us understand how planets and stars form and develop.
None of which will give me brighter, whiter teeth; help me find an exciting, rewarding, career; or win the lottery. But I'm human, and I've been over that before: often. (March 18, 2016; March 3, 2016)
More:
- "Hot super-Earths stripped by their host stars"
M. S. Lundkvist, H. Kjeldsen, S. Albrecht, G. R. Davies, S. Basu, D. Huber, A. B. Justesen, C. Karoff, V. Silva Aguirre, V. Van Eylen, C. Vang, T. Arentoft, T. Barclay, T. R. Bedding, T. L. Campante, W. J. Chaplin, J. Christensen-Dalsgaard, Y. P. Elsworth, R. L. Gilliland, R. Handberg, S. Hekker, S. D. Kawaler, M. N. Lund, T. S. Metcalfe, A. Miglio, J. F. Rowe, D. Stello, B. Tingley, T. R. White; Nature Communications 7, Article number: 11201 (Received September 7, 2015; Accepted March 1, 2016; Published April 11, 2016) - Wikipedia
4. Still Searching for Neighbors
(From Seth Shostak, SETI Institute; via Space.com, used w/o permission.)
("The SETI Institute's Allen Telescope Array in Hat Creek, California is now searching 20,000 red dwarf stars for signs of intelligent life."
(Space.com))
"SETI's New Alien Life Hunt Targets 20,000 Small, Dim Stars"The Space.com article included an informal, highly-unscientific poll: asking "Do you believe alien life exists elsewhere in the universe?" I was the 55,742th respondent. The results weren't terribly surprising:
Mike Wall,Space.com (March 31, 2016)
"The search for intelligent aliens has expanded to include thousands of star systems very different from that of Earth.
"Scientists with the SETI (Search for Extraterrestrial Intelligence) Institute in Mountain View, California have just begun a two-year hunt for signs of alien civilizations around 20,000 red dwarfs — stars considerably smaller and dimmer than Earth's sun.
"Red dwarfs are promising targets for SETI scientists. They are the most common stars in the Milky Way, making up about 75 percent of the galaxy's stellar population. And because red dwarfs burn through their fuel slowly, they live a long time; on average, the Milky Way's red dwarfs are billions of years older than the sun, researchers said...."
- Yes - We may not have found them yet, but they're out there.
64% (35902 votes) - No - Aliens are just part of science fiction.
20% (11277 votes) - I'm not sure
15% (8563 votes)
"Belief in Extraterrestrial Life:" Certainty, Uncertainty, and Religious Affiliation
(From Survata, used w/o permission.)
My guess is that a Survata poll of Americans, done in 2013 or thereabouts, is a tad more accurate. In that one, roughly a third of American Christians, Jews, Muslims, Hindus, and atheists/agnostics weren't sure about whether we have neighbors.
Interestingly, over half of "other" 'believe in the existence of extraterrestrial life.' That may help explain why some American Christians are adamant that life mustn't exist anywhere except Earth.
Like I said, I'm not sure. We either have neighbors, or we don't. Right now, we don't know, and I'm okay with that.
I hope we do have neighbors. For one thing, it would make this universe seem a bit less empty.
For another, comparing notes with folks who aren't human would be an opportunity to learn how much of 'human nature' comes from being critters with free will and bodies; and how much is strictly "human."
My guess is that we'd learn that a great many of our neighbors are fine folks: but not "human." At all. Which is why I think nearly every SETI effort makes unwarranted assumptions.
Tesla, Pulsars, and "Wow!"
SETI is part of the SETI Institute's name. (www.seti.org)It's also a generic term, the Search for extraterrestrial intelligence's acronym. Like ancient Romans, Americans use a lot of acronyms, and that's still another topic.
I'll be talking about SETI in general. Current efforts arguably began in 1896, when Nikola Tesla said that he should be able to communicate with Martians with his wireless electrical transmission system.
He thought he had detected Martian signals in 1899, at his Colorado Springs experimental station.
I gather that Tesla's oddly-regular static might have come from Marconi's European radio experiments, static from Jupiter's plasma torus, or something else that wasn't Martians.
Or maybe someone was trying to get a distress call to the nearest rescue station — using badly-damaged equipment.
If that's the case, which I think is extremely unlikely, we'll eventually find them; or the equivalent of a SAR ship is on its way — or was here, and left.
We've had SETI false positives since then, including PSR B1919+21 (1967) and the 1977 "Wow! signal."
I gather that Susan Jocelyn Bell, a graduate student at the time, and Antony Hewish, her thesis supervisor, wanted a reason to not identify the thing as an artificial beacon. They were both professional scientists, and had careers to think of.
"...At this point, Burnell notes of herself and Hewish that 'we did not really believe that we had picked up signals from another civilization, but obviously the idea had crossed our minds and we had no proof that it was an entirely natural radio emission. It is an interesting problem—if one thinks one may have detected life elsewhere in the universe, how does one announce the results responsibly?'..."Later, after more rapidly-pulsing radiation sources showed up in other parts of the sky, they started looking more like a previously-unknown natural phenomenon.
(Pulsar, Discovery, Wikipedia)
Or maybe a network of navigation beacons. Each one pulsed at a slightly different rate: and much, much faster than a star should be able to.
Eventually we caught one slowing down, and decided that highly magnetized rotating neutron stars were the best explanation for observed data.
I'd love to think that there's a vast civilization using pulsars as a sort of galactic GPS system: but I figure the scientists are right.
The Universe, Life, and Us
Recent (1950-to-current) SETI efforts have tried detecting artificial radio signals from promising sections of the sky, from specific nearby sun-like stars, and now we're trying pretty much the same thing for red dwarf stars.I don't think the efforts were a waste of time and effort. Folks collected a great deal of data, which should help us understand this universe.
But I'm pretty sure that there's nobody like us within several dozen light years. Whether or not we've got next-door neighbors: is another matter.
Like I've said before, SETI generally makes some whacking great assumptions. (July 24, 2015)
We use modulated radio signals for long-distance communication. We could use off-the-shelf tech to chat with folks on planets circling nearby stars: if they're there, and if they use radio, too. Maybe they do. Then again, maybe not.
Let's assume that there's a planet almost exactly like Earth orbiting Alpha Centauri A, a star that's almost exactly like ours. Almost:
- Mass 1.100 M☉
- Radius 1.227 R☉
- Luminosity 1.519 L☉
(Source: Wikipedia)
Two more: let's assume that people (that's one) living on that Earth-analog are almost exactly as 'old' as we are (that's the other).
In other words, that they got started within 1/1000th of their world's age as we did. That's 4,540,000,000 times 0.001 = 4,540,000 years. That's a long time.
Instead, let's assume that they're 1/4,540th Earth's age old: that's 1,000,000 years.
A million years back, we were making almond-shaped stone hand axes.
If that's where our neighbors are at, they probably won't build their first radio for another 999,881 years. (June 19, 2015)
If they started 1/4,540th Earth's age before we did, they were probably using radios when we worked the bugs out of those hand axes: and are currently using whatever we'll invent a million years from now. (June 19, 2015)
My guess is that talking drums, slit gongs, and the Inmarsat network are the not the ultimate communication technologies. (July 24, 2015)
I also suspect that people aren't necessarily as incurably chatty as we are. (January 15, 2016; July 24, 2015; June 27, 2014)
Maybe we have neighbors who have more in common, psychologically, with cats than chimps. That would go a long way toward explaining why we haven't heard anything so far. (August 2, 2015)
Cats don't have pack or herd behavior. They're smart, and social in their own way: but cats don't "act collectively without centralized direction." (Wikipedia)
This doesn't mean we should give up on looking for neighbors. I think, however, that SETI projects would be well-advised to stop looking for signals from the stars, and start looking for indirect evidence that people are at work.
That'd be something fairly small, and not acting like a natural phenomenon: an infrared source in what looks like empty space, unusual concentrations of one heavy element or molecule, and that gets me back to pulsars. (September 26, 2014)
That's assuming that people always develop and use technology on an increasingly-large scale. Maybe we haven't detected our neighbors because they're all quietly contemplating the suchness of sibilance, itemize the enigmatic, or watching the local equivalent of grass grow.
Reassuringly "Human" — and Otherwise?
Then there's physical appearance. If — and that's a big "if" — we have neighbors, we may learn that that folks who look like Mr. Chuckles there are the most reassuringly 'human' of the lot.Whatever they look like, and however they think, if we do have neighbors — I'm pretty sure that some folks will be upset, others won't care much one way or the other, and at least one religious order — Jesuits, most likely, or their analog in the nth century — will get to work learning their language.
And that's — you guessed it — another topic. (August 2, 2015; July 18, 2014; June 27, 2014)
Had enough? If not, here's more:
- "Seeking New Worlds, New Life - - -"
(March 3, 2016)
Particularly - "SETI: Looking for Neighbors"
(January 15, 2016)
Particularly - "Enceladus and Kepler's Planets"
(December 18, 2015)
Particularly - "Pluto's Unexpected Terrain; SETI, Radio, and Drums"
(July 24, 2015)
Particularly - "Habitable Worlds, Homer, and Haldane — or — Ganymede's Oceans, and Imagining Kepler-186f's Sunsets"
(May 9, 2014)
Particularly
1 I've talked about the Alcubierre metric before. From what I've read, some scientists and mathematicians still say an 'Alcubierre drive' shouldn't work. They could be right.
But I think it's significant that objections to building ships whose engines use the Alubierrie metric have shifted from 'it's impossible' to 'it's impractical' and 'it's dangerous.' About the latter: I'm pretty sure they're right. Any technology, from fire to sewing machines, is dangerous if we're not careful. The trick is being careful.
More of my take on fire and other dangerous technology:- "Reaching for the Stars"
(March 25, 2016)
Particularly - "SpaceX, Mars, and Someday the Stars"
(December 24, 2015)
Particularly - "DNA Test Hype; and Studying Life's Origins"
(December 5, 2014)
Particularly - "Schrodinger's Cat(s); and Gravitational Waves, Revisited"
(September 26, 2014)
Particularly
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