Even with my general (and limited) understanding of biology, that unless it’s forbidden by the laws of physics, nature generally does anything and everything you can imagine… This one blew my mind.
And not just once, with creatures having eyes on their shells, but with the number of times eyes have evolved within just that genus (remember: domain, kingdom, phylum, class, order, family, genus, species), and also the correlation between nerve holes in the shell and eye complexity.
Won’t you come, and wash the rain away? For those in California and around the world laboring under a deluge from the sky, perhaps this video from the frontiers of astroseismology will be entertaining and informative, if not comforting.
“What if there’s a black hole inside the sun? Hawking Stars from PBS Space Time”
The short version is that it’s not implausible for a microscopic black hole to enter the sun, start consuming material and producing back-pressure against the massive gravity. As you can imagine, its growth eventually alters the life cycle of the star, but perhaps more subtly than you’d think.
And, back in the context of SETI and general cosmology, while we’re pretty sure our Sun doesn’t (yet) have one, it is encouraging to think that we can place constraints on the number of primordial black holes there are flying around out there, as well as confirm or rule out some dark matter theories.
Some of my favorite moments in science are when we find something that we didn’t think was possible. I also think that’s a good way to describe a SETI experiment: an non-nature detector, sifting through the universe looking for something we don’t think nature does.
Today’s instance is an invisible pulsar companion with a mass much larger than a typical neutron star, perhaps the largest on record, and in the range where it’s expected to collapse into a black hole, essentially at or above the “TOV limit.” I’ll let Science News explain.
An unseen object orbiting a pulsar might be an exceptionally lightweight black hole (illustrated), a very heavy neutron star, or something else entirely. Credit: DANIËLLE FUTSELAAR/ARTSOURCE.NL
One of the things that’s so great about the era of science that we’re living through, is the steady pace of amazing discoveries–almost to the point that they’re predictable. Exoplanets, the Higgs boson, the age of the universe, gravitational waves, and many others were foreseen and experienced regular progress until their ultimate discovery.
These areas of science are foundational to SETI, but I think the connection is deeper. Everything we’ve learned about the universe suggests the possibilities for abiogenesis elsewhere in the universe are endless. But simple life doesn’t build transmitters or starships. And, as essentially a brand new technological civilization on the timescale of our star, galaxy, or universe, our ability to predict how and how often other civilizations might evolve could not be more limited. We have no exobiology, exospychology, or exosociology–only physics and chemistry which are universal by definition.
Hopefully that explains why I’ve said for a while now that I view the search for technosignatures as in a race with astrobiology. I picture it like the children’s story of the race between the tortoise and the hare. Astrobiology is the tortoise, making regular progress but always painful to wait for the next instrument or discovery. It’s not actually slow, it’s really amazingly fast that we get to watch a fascinating science unfold in real-time, but it’s hard to wait for things you’re excited about! SETI, of course, is the hare, the rabbit that makes rapid spurts of progress. Who knows when and how a signal might be found and, reliant on unpredictable private funding, technosignature projects–like LaserSETI!–show up irregularly and take as big a bite out of the problem as they can.
And so that’s the background which makes NASA’s announcement of observations of “habitable zone” exoplanet K2-18b an exciting step for the astrobiology tortoise. Using a technique called transit spectroscopy (see Update at bottom of post), which measures starlight passing through the planet’s atmosphere while it’s between us and its host star, they’ve identified a chemical composition that indicates it’s potentially a water world. And, especially tantalizing, there’s also hints of dimethyl sulfide (DMS) which, on Earth, is only produced by biology. It’s “the most abundant biological sulfur compound emitted to the atmosphere” and so makes a credible candidate for the first biosignature gas we might detect.
Spectrum of Exoplanet K2-18b’s atmosphere, showing molecular composition (credit: NASA et al)
Stay tuned because it’s too early to say if this DMS is a real or just a trick of the noise in the limited data they’ve been able to collect thus far. After all, we can point the telescope wherever we want, but we can’t make the “K2-18 year” to happen any faster to produce more transits!
Would I be disappointed if astrobiology beat SETI to discovering other life in the universe? Absolutely not! The most interesting scientific discovery of my lifetime will be amazing whoever makes it, and it will only hasten the search for technosignatures and answering the other half of the question, “are we alone?”
Update: Here’s a great illustration of transit spectroscopy:
One of my favorite aspects of SETI work is the scientific breadth required. While no one can be an expert in everything, every corner of human knowledge has the potential to affect SETI theory or practice.
So while this video does discuss spectroscopy, I hope you’re now in the muod for some mind-bending atomic chemistry that’s admittedly only peripherally related to LaserSETI.
After watching the video, in case you’re wondering: yes, it technically is an isotope of hydrogen since its atomic number is the same. Its nucleon count, however, is zero. If that seems odd, just wait, it gets better. Since there’s a third type of lepton, there’s not one but two hydrogen isotopes of nucleon count zero. 🤯
If your head is hurting by this point, perhaps you should drink a nice, cold glass of dihydrogen monoxide.
I recently returned from the “The First Annual Penn State SETI Symposium” which I have to say was both successful and enjoyable. Great topics and talks, diverse and smart attendees, and everywhere you looked people were collaborating and learning from each other.
I’m told videos of the presentations will be published on their site soon, and the posters are already accessible here.
Tomorrow night, May 26th, I’ll be kicking off the annual Ferguson ObservatorySpeaker Series. We’ll start from SETI basics, explain how LaserSETI is designed, and take questions. It’s free, it’s virtual, and they’ll give you your money back if you don’t learn anything!
RFO Speaker Series: The LaserSETI project with Eliot Gillum
Join RFO and Eliot Gillum for the SETI Institute for an informative conversation on the LaserSETI project!LaserSETI is an ambitious project to continuously scan the whole sky for laser flashes from beyond the Earth-Moon system, ostensibly from another civilization. The first two instruments in this…
When it was announced a couple of years ago, I thought VASCO was a great idea and important work. Today, an article was published “70-Year-Old Astronomy Photos May Be Clues to Alien Visitors“, and despite the accurate but click-bait-sounding title, I’m glad to see they’ve done that work well, with great care and attention to detail. As with any general audience article on science or medicine, I encourage everyone to at least open the original paper to see what else you can glean from it, especially since this is a pre-print and is expected to evolve before publication.
Sample candidate, credit: Villarroel et al
While I’m quite pleased with the quality of both the article and the paper, I’d feel like I was leaving something out if I didn’t say that, based on what I see in the paper, while I agree the linear structure indicates fast-moving objects, I don’t think one can assume that the whole event is captured by a single plate, and thus we’re unable to constrain its angular velocity and therefore altitude. That puts them well within the range of a lot of high-speed and high-altitude experiments being done in southern California at the time, including the infamous Area 51, in Palomar’s neighborhood.
Map showing 10 different military bases near Palomar Observatory, credit: Bing Maps
VASCO has some great ideas of other catalogs to analyze, which I think is the right next step in any case. They’ve shown there’s some interesting events to be explained in our collective archives, and science is always better (and easier) with many data points. I look forward to seeing how this story evolves!
Astrophysical masers are a well known phenomenon when molecules within a stellar atmosphere get excited and emit coherent photons. When it happens around an (active) galactic nucleus, it’s proportionately brighter hence the aptly-named megamaser.
To be clear, astrophysical masers are different than what LaserSETI is looking for in a number of ways. First, these are radio waves, not visible light. Second, they shine equally in all directions (isotropic) vs. human-made lasers which are a focused beam (spatially coherent). Third, they don’t turn on and off like a light switch.
