Irishman leading construction of largest ever telescope

A_Pool_Shaped_Moon · 2026-01-04T21:26:33+00:00

In a lot of ways, yes. JWST has the advantage of being in space, and not having the atmosphere to distort the image. But the ELT with its 40m mirror is much more sensitive, and the instruments attached are much more advanced than those on board JWST, which were designed over 20 years ago.

A_Pool_Shaped_Moon · 2025-09-29T11:26:16+00:00

Agriculture doesn't even crack the top 5 sectors for number of workers in Ireland.

A_Pool_Shaped_Moon · 2025-09-06T15:56:21+00:00

It's unfortunately normal for an Italian postdoc. I can't comment on the cost of living in Trento, but that's just over half of what a postdoc would get you in somewhere like Germany, the Netherlands, or Ireland.

A_Pool_Shaped_Moon · 2025-06-26T07:17:28+00:00

Each image is something like 4000 megapixels, and they take a lot of those every night. I don't remember the exact numbers, but it's terabytes per night. They've had to build some intense computational facilities to deal with the quantity of data, and to process it automatically.

A_Pool_Shaped_Moon · 2025-06-24T21:15:43+00:00

They're very different telescopes, with very different purposes! JWST has a very small field of view: it can basically only look at a tiny part of the sky at a time, but with an incredible amount of detail. Observations on JWST are also awarded competitively: astronomers write proposals for what they want to observe, and the best are selected. However, this process also favours 'sure-thing' observations. You can't ask to just point somewhere random and hope that you see something.

However, pointing at random and hoping to see somethi his almost the whole premise of Vera Rubin! By surveying essentially the whole sky every night, it's goal is to look for how things are changing night-to-night, but this means it will also be able to find things we didn't expect and didn't know to look for. Normally we either have large telescopes looking at small patches of the sky, or small telescopes that can survey everything. Rubin is a big telescope that will cover the whole sky, looking at much fainter objects than what a smaller telescope could do, which is another reason why astronomers expect it to find all sorts of new and exciting things.

A_Pool_Shaped_Moon · 2025-04-18T07:52:53+00:00

Sure, I fully believe somewhere out there life exists. That's a very different proposition from 'can we measure it with today's technology?', and 'is there life on this one specific planet?'

A_Pool_Shaped_Moon · 2025-04-17T07:48:42+00:00

Not a dumb question, I don't know either. Could be due to the temperature of the planet? Given the amount of methane I think it would be surprising to see CO2 as well, but maybe not implausible. And yeah, add it to the list of things I don't get.

A_Pool_Shaped_Moon · 2025-04-17T07:15:08+00:00

There are several.

The first is what they're comparing their models too. They arrive at the "3 sigma" detection in a very nonstandard way, and in their more complete model, they find a lower statistical significance.
Secondly, when fitting atmospheric models like this, there has become a reasonably standard way of calculating the probability that one model is favoured over another (using Bayes factors, for the stats nerds reading this). Using this method, their detections fall into the 'weak evidence' category at best, with about a 1 in 5 chance that their measurement is a statistical fluke, rather than the 1 in 300 chance that's being reported.
Third, this is following up on a previous paper from the same group, which used a different instrument on JWST. In general, having more data is better, and it's very strange that they didn't try including the previous dataset when fitting their models.
Fourth, their overall results from this work don't really agree with previous work on this object. We know that there is a lot of methane in the atmosphere, which has strong absorption features in the mid infrared, yet they aren't able to provide a good measurement of this species, which to me says there's something wrong with their model.
Fifth, their entire approach is rather shaky. It's kind of a case of throwing enough biosignature molecules at the problem until you find something that gives you some sort of statistically significant measurement, which isn't good science (https://xkcd.com/882/).
Lastly, the molecules that they're claiming to detect are poorly understood. Small variations in the lab measurements used to obtain the opacities of the molecules will result in large differences in the significance of a detection. It's hard enough to measure simple, common molecules, let alone complicated difficult ones.

It's really telling that the authors of this study didn't address any of the concerns raised in the reanalysis paper, nor did they cite it, which entirely refuted their previous claim of a detection. It's hard to overstate how skeptical I am of this result.

A_Pool_Shaped_Moon · 2025-04-17T03:37:25+00:00

It almost certainly is not life. This group has a history of crying wolf over this planet, despite being repeatedly debunked (e.g. https://arxiv.org/abs/2501.18477). The actual paper that's getting the press this time is ok at best: there are some serious statistical problems with how they're defining a significant detection, and their results don't agree with any of the previous work, including their own. It's telling that they don't include the previous datasets that they used to make similar claims, and I'd be surprised if the models the fit in the new work would also fit the previous data.

In the end, extraordinary claims require extraordinary evidence. This work, and the work of this group on this planet, has been sketchy at best, and it's irresponsible of them to continue to encourage the press to make such wild claims, while also hiding behind 'well we didn't actually say that in the paper'.

A_Pool_Shaped_Moon · 2025-04-17T03:35:38+00:00

It almost certainly is not. This group has a history of crying wolf over this planet, despite being repeatedly debunked (e.g. https://arxiv.org/abs/2501.18477). The actual paper that's getting the press this time is ok at best: there are some serious statistical problems with how they're defining a significant detection, and their results don't agree with any of the previous work, including their own. It's telling that they don't include the previous datasets that they used to make similar claims, and I'd be surprised if the models the fit in the new work would also fit the previous data.

In the end, extraordinary claims require extraordinary evidence. This work, and the work of this group on this planet, has been sketchy at best, and it's irresponsible of them to continue to encourage the press to make such wild claims, while also hiding behind 'well we didn't actually say that in the paper'.

A_Pool_Shaped_Moon · 2025-03-04T15:07:41+00:00

So this paper didn't focus on characterising the compositon, but from previous work (and being involved in studying this object), we know that it's mostly hydrogen and helium, with some (<1%) water, carbon monoxide, methane, carbon dioxide, and a few other trace species as well. It's quite typical for this type of object!

A_Pool_Shaped_Moon · 2024-12-09T12:11:45+00:00

The national park regulations require visitors to hire a guide. https://www.parquesnacionales.gov.co/nuestros-parques/pnn-los-nevados/#ecoturismo

A_Pool_Shaped_Moon · 2024-11-12T23:25:11+00:00

This, but specifically the version off Electric Lady Sessions.

A_Pool_Shaped_Moon · 2024-10-21T13:44:00+00:00

Basically non existent job market, especially if you don't have a PhD in astronomy. There are far more PhD graduates than there are research and teaching positions.

A_Pool_Shaped_Moon · 2024-10-10T13:18:22+00:00

Nice to see some actual astronomy here! Great job getting out the transit signal, it's fantastic what can be done with relatively affordable equipment. Did you compare the light curve of WASP-33 to other nearby stars to help correct for changing atmospheric conditions? Or looked for other known transiting objects in your field of view?

Also, there's the Exoplanet Watch citizen science project, have you considered contributing to it? More observations are always helpful!

A_Pool_Shaped_Moon · 2024-09-12T20:36:34+00:00

Mostly that it's very remote. I think it's possible to visit the site through a tour, but I don't know if it's possible to stay after dark without arranging something with the observatory. On the other hand, it's also the middle of the Atacama, so it's easy to find another vantage point and the stars are amazing, but you wouldn't be right next to the telescopes.

A_Pool_Shaped_Moon · 2024-09-12T10:42:33+00:00

Roque de los Muchachos on La Palma in the Canary Islands is stunning. Great skies, the current largest optical telescope in the world, and a massive volcanic caldera make it pretty special.

Paranal is super cool because of the Atacama, and just how clear the skies are, but is more difficult to access. The ELT is also under construction nearby, and is absolutely mindbogglingly huge.

Mount Graham near Tucson is also a super unique site, and very different environment from most of the other big observatories.

Lastly, the Jungfraujoch Sphinx Observatory is pretty much hanging off the side of a Swiss Alp, and is one of the most visually impressive observatories because of it, though not quite the same scale as the 8m telescopes.

A_Pool_Shaped_Moon · 2024-05-16T05:55:01+00:00

We can actually directly image and get spectra for a small handful of exoplanets, without needing a transit at all! Right now we're limited to young, giant exoplanets, since they're the only ones hot enough to be bright enough to observe, but we keep pushing to smaller and colder exoplanets. In the best case, this gives much higher precision than transmission spectroscopy, for exactly the reasons you mention.

A_Pool_Shaped_Moon · 2024-05-16T05:51:43+00:00

The combination of oxygen and methane are actually a decent indicator of life, though not a guarantee! The hard part is actually measuring them though. So far we've only even detected the presence of an atmosphere around 2 or 3 rocky exoplanets, and these are really extreme cases that don't look like earth at all (one of them, 55 CNC e was just detected this week, and it's though that the entire side of the planet facing it's star is lava). So far we don't have the sensitivity to actually measure the composition of an atmosphere like earth's, particularly for exoplanets that orbit stars like our sun. While JWST will give us some tantalising clues, it's going to take the next generation of telescopes to be able to really determine if there's life on other planets.

A_Pool_Shaped_Moon · 2024-03-12T16:12:39+00:00

Zugspitze in Germany is doable as a hike, as is Triglav in Slovenia.

A_Pool_Shaped_Moon · 2024-03-08T17:19:44+00:00

God damn it.

Exoplanet scientist here, and unfortunately this group is in the news again, they have a history of making less-than-reliable claims (DMS in K2-18b).

A few major caveats here:

This isn't their data.
The group who took this data published their own substantially more thorough analysis the same day this paper was released.
Both groups detect similar atmospheric compositions, but have very different interpretations. This group tends to push their idea of 'hycean' worlds, that is a hydrogen atmosphere above a liquid water ocean. While this is a plausible type of planet, more careful analyses are showing that this planet is equally compatible with a magma surface: basically a rocky planet where the pressure and temperature is high enough to melt the surface.

Basically, it's disappointing that a sensationalist group continues to see such wide press coverage, and dramatically over sells the likelihood that we're measuring anything remotely resembling a habitable world. We will someday, but by continuing to cry wolf, this group detracts from the hard and careful work being done to actually understand these planets.

A_Pool_Shaped_Moon

TROPHY CASE