BBC's Science in Action [1] But as always, it starts with something flaring up briefly in the night sky. And for Ashley Villa, the challenge is choosing which supernova to pay attention to.
Ashley Villar
So we discover about 10,000 supernovae every year right now. So we can't, in real time, do detailed investigations of exactly what's happening. So we have to pick and choose our battles. And my group takes the very specialised approach of saying, well, let's capture the most exotic physics. Often, that means that we don't quite know what we're looking for. So what we use now are machine learning algorithms. So we literally have this algorithm that is listening to alerts from a telescope every night. And he does some basic statistics about the properties of the light over time from the explosion and the home, so the galaxy that the explosion came from, to say, oh, this looks weird compared to everything else that I've been looking at. And this one, whose name is 2023 ZKD, it showed up because it had kind of risen somewhat slowly, but not that abnormally. And then it was just starting to decline. And our bot said, hey, it's declining a little more slowly than I would expect. And so it flagged it as one of the most anomalous.
Roland Pease
I guess my normal picture of a supernova is you have this star, it explodes. Yeah. So you get a very bright flash. And then as all the junk goes away, it fades slowly. And you're saying that it didn't explode quite bang like that. And then it sort of also kept going for a bit longer than you expected.
Ashley Villar
But you're exactly right. This guy looks like I'm rising a little slowly and I'm now declining a little slowly.
Roland Pease
But it turns out yours is way more weird than that.
Ashley Villar
Yes. So to be clear, like at this point, we say, oh, this looks interesting. You know, like, I don't know. I would have actually said it's so unusual. We put in our observing cue. A few months later, we finally do get a spectrum.
Roland Pease
That tells you what the elements are that were in the star.
Ashley Villar
That's correct. We noticed that the star somehow had polluted his surrounding environment with hydrogen and helium. Like so much so that seems like he actually had all his hydrogen stripped off of him at some point. So that was weird. That is not how our sun looks. That's not how most stars look. So that was interesting. We then also said, oh, let's like go back in time and run our more specialised algorithms on the images we took over time to look deeper. And when we did that, we actually noticed that this thing had been slowly brightening for well over a year. And that's very weird. Supernovae do not like announce when we're about to explode. But this guy did. And then a few months later, it looks like it exploded again. So just all around, it was just bizarre situation.
Roland Pease
This is a long, long way away. So you don't even know what star it was. No, you seem to not know very much about the galaxy it was in even.
Ashley Villar
That's right. So this was 700 million light years away. So this is not nearby by any means.
Roland Pease
So you're looking at spots of light, basically, and trying to interpret them.
Ashley Villar
Yeah. Even the galaxy he is from, if you look at the image, it's like a tiny little block.
Roland Pease
The bit that caught my eye was that you're saying that involved in all of this, there's not only a star, but a black hole.
Ashley Villar
OK, so this is why it's going to take so much data to interpret what the heck was going on. So the things I pointed out, this kind of double peak, which I said two explosions, not two explosions, but has these two kind of bright, dim, bright, dim, and then this long rise. And then also the spectroscopic signatures. So the way that the hydrogen and helium looked in the spectrum all match very recent theoretical predictions for what should happen if a massive star is spending the end days right next to basically similar mass black hole companion. And our idea is that that black hole is kind of ripping away at that star and they are merging together.
Roland Pease
This is weird. So the brightening would be as it's ripping the atmosphere off the outer part of the star, that's sort of why you're seeing a bit of extra brightening.
Ashley Villar
That's right. So we think that the reason why the local environment is so weird is because that black hole is ripping off material. And that's the long ramp off that we see. It's that material kind of being ripped off of breathing onto the black hole, messing up the local surroundings of that star. Then the star goes supernova. And then that supernova hits the kind of cloud of stuff that he's been losing because the black hole has been ripping him off. And that's where the double peak comes from.
Roland Pease
Okay. This is so weird. So the big star is orbiting the black hole and we see something a bit like that. Sometimes we see small stars, white dwarfs orbiting other neutron stars and things like that. So that's not out of this world, but the black hole is so disturbing, this giant star.
Ashley Villar
That's correct.
Roland Pease
I mean, it does sound amazing.
Ashley Villar
So I think what's so exciting about this is that it came at a very special time where we have seen this type of phenomenon a few other times. There were two other events that had this kind of long rise up or this double peak in a way that looked similar. However, this is the first time because we were able to trigger early enough on it that we were able to tell a very complete story that really definitively put to us a nail in the coffin that, okay, this is definitely some sort of merger with a black hole companion. So we think in that way, it's really shining light into this new glass.
Roland Pease
And that's, I think, where the new telescope, the Vera Rubin, which we talked about a couple of months ago, is really going to come into play because it's going to see lots of these, I guess.
Ashley Villar
Yeah. So I'm so pumped. I said we discover right now about 10,000 supernovae every year. Vera Rubin should observe about a million every year. So it's just this incredible increase. And what's so fun about it is that it's this very unprecedented movie of the southern sky. So it looks very, very deep. And it has such a wide field of view that it can look at the whole southern sky every few nights. And that just means it's a supernova discovery machine.

[1] https://www.bbc.co.uk/sounds/p...
[2] https://ui.adsabs.harvard.edu/...

I don't disagree, but such figures have to be used with care, there is a distinction between the rate of cancer and the rate of detection of cancer. It's possible that the better treatment of cancer comes from earlier detection.

An antivax site I read claims that the rate of autism in US children has increased (from the use of adjuvants that cause inflammation in vaccines). It's quite possible that it has remained steady but the detection and diagnosis has changed.

Why do they select the pions for a certain momentum?

Fascinating! Thank you.

It hadn't occurred to me that neutrinos could be generated with a preferred direction. Would someone care to explain how it is done?
I asked Gemini and I post excerpts form its replies. I'm confident enough to reject one but I don't know about the other
- How can one send a stream of neutrinos?
-- "By colliding high-energy particles (like protons or electrons) in a particle accelerator, neutrinos can be produced as a byproduct. These neutrinos can then be directed using magnetic fields, but controlling their specific path is difficult"
- if we direct protons at a target, do the resulting neutrinos have a preferred direction?
-- "The total momentum of the system must be conserved. This means that the direction of the neutrinos will tend to be opposite to the direction of the incoming protons."

your software will continue to work but will slow down progressively until the licence is renewed.

"AAVSO (variable star observers) posted a news alert for it's observers a while ago"

From https://iopscience.iop.org/article/10.3847/2515-5172/ad235f

"the first planet makes three orbits for every two of the second planet. The exact same dynamics play out between the next two planets. The fourth planet is computed to make four orbits for every three of the fifth planet, which, in turn, makes four orbits around the star for every three of the outermost planet."

Of course, there are asteroids in similar resonance with Jupiter and Io, Europa, and Ganymede are in a 1:2:4 resonance around Jupiter

It's a time capsule and I heartily approve. There was a TV programme called Survivors in which disease caused a societal collapse and I sometimes play with Gedankens about what I would do. One thing I would like to do is bury a time-capsule containing a copy of our history and culture as a message across time. One problem with this is that barbarians might dig it up thinking it was treasure and discard it when they realised it was useless to them. Putting it on the moon ensures this wouldn't happen. If lunar explorers from our culture came across one wouldn't we rejoice that someone had thought to do it?

See also the examples on this page from UK's BBC

Here is another write-up

It's possible, even probable, that I'm making an elementary blunder so someone correct or confirm please? According to Wikipedia, 1 TeV is the kinetic energy of a mosquito and proton/proton collisions are 13 TeV but CERN uses 13 TeraWatt hours. I appreciate that 1 mole of mosquito has a lot of atoms (10^23?) and presumably that's why an accelerated proton and a bumbling mosquito have roughly the same energy, but how does CERN use up so much energy? Is it the number of particles it accelerates? (and does that energy get used for heating houses afterwards?)

Oh Rats! "but not say there is a correlation" should be "but not say there is causation"

Those articles, even the newspaper one, are careful to report on a correlation between mask-wearing and a reduced infection-rate but not say there is a correlation. Even in the stanford.edu experiment, in which the villages were chosen at random, the correlation might be because of a change in behaviour by the villagers.

Similarly, there is a correlation between infection and death from covid-19 and installation of 5G masts but the authors are careful not say whether it is causation. For example, it may reflect a difference in population that made phone-companies prefer to install 5G in some cities over others.

The writer is confused. It's true that the telescope is headed for an L2 Lagrange point but it's the sun-earth L2 point, not the earth-moon L2 point.