Sunday, October 17, 2021

Joe Manchin's Excess Deaths

For some reason Tweets are no longer properly embedding in Blogger, so I have to cut and paste them. Blogger sucks more and more all the time.

Sunday, October 10, 2021

My Article on Technosignatures

I also have a feature article in this month's issue of Physics World magazine, on technosignatures:

“Scanning the cosmos for signs of technology,” Physics World, October 2021, pp 32-36.

At the moment it's only available to registered users of the site, but registration is free. In a week or so there'll be a publicly available link and I'll post that then. 

"Technosignatures" are any sign of technology on another planet. Examining the "technosphere" is a burgeoning field that astronomers and astrophysicists are starting to think about, especially as the James Webb Space Telescope is about to launch (December, they say now) and as even better telescopes might come online next decade if recommended by the forthcoming NASA Decadal Survey. 

For the last two decades astronomers and astrobiologists have been thinking about how they might detect life on exoplanets, via "biosignatures." These might be the detection of methane in a planet's light spectrum, large amounts of oxygen, and a host of other possibilities, due to microbes or plant life. If life is ever detected on another planet, it's likely it will be via some type of biosignature -- it could happen in the next couple of decades.

Just in the last couple of years scientists have also begun thinking about "technosignatures," signs of technology akin to how biosignatures are signs of life. If other planets have an advanced technological civilization, akin to ours or more advanced (since ours is rather nascent), there may be signs we can detect astronomically. These might be city lights on their nightside, industrial pollution in their atmosphere, solar panels on their surface or in orbit, or megastructures like a Dyson sphere* or swarm or ring, or who knows what. People are making calculations of what might be detectable by the Webb telescope or TESS, and by telescopes that are hopefully recommended like LUVOIR and HabEx. There will be an enormous amount of data to sift through, looking for anomalies. I tried to cover some of this rapidly expanding field in my artice. 

* As you may know, a Dyson sphere is a hypothetical structure that would completely surround a star, thereby capturing all of its energy output. (Such an structure around our Sun, at Earth's distance, would capture 2 billion times as much solar energy as falls atop Earth's atmosphere.) Except a Dyson sphere isn't mechanically stable -- they would likely break up due to any drift, as Dyson wrote about in 1960 when he first proposed this idea. (A Star Trek: The Next Generation features a Dyson sphere. [Video] Magically it was stable.) If it could exist, a Dyson sphere would heat up and radiate outwards. A Dyson sphere at Earth's orbital distance would radiate at Earth's brightness temperature, 255 K, so with a blackbody spectrum with a peak wavelength of about 10 microns, in the infrared. People have actually done searches for Dyson spheres in the galaxy. 

Instead, a civilization might construct a more stable Dyson configuration like a swarm or ring or bubble -- I've used the figure from my article below. Why? One idea is to capture solar energy on them and beam microwaves to the planet's surface. But who knows what an advanced civilization might do with them -- maybe live on them! These should have a radiative signature too, a technosignature. It's all hypothetical of course, but fun to think about.... It was a fun article to write.

Friday, October 08, 2021

My Wash Post Article

I have an article in today's Washington Post. It's accompanied by a nice piece of artwork, by Amy Ning

"The climate crisis is spawning weird ideas to fix it. They might be all we have."

"The Trick" Trailer by the BBC

Not a fan of the title.

Thursday, October 07, 2021

YouTube Bans Ads on Climate Denial Videos

 This is big; NYT:

Can't wait to hear all the whining.

Google also owns Blogger (blogspot blogs, like this one). Wonder if its climate denying blogs are next. I'd guess not.

Nb: corrected my original headline.

Wednesday, October 06, 2021

A Trillion Dollar Coin

Tuesday, October 05, 2021

Nobel Prizes for Climate Science

Today's Nobel Prizes in Physics goes to three men who played very important roles in the early development of climate science and the analysis of complex dynamical systems. Quanta magazine has a good summary

At first I was surprised, because it wasn't awarded to anyone in fundamental physics research, as usual. But then I realized it made perfect sense, and sends an important message as well, and just before COP26. 

I'm more familiar with Manabe's work than the other two. In fact, a few years ago I wanted to profile Manabe for Yale Climate Connections, but he wouldn't do an interview. Beforehand I had read some of his early papers with Richard Wetherald -- Manabe did the physics, Wetherald did the computer programming -- such as this famous 1967 paper, and they were remarkably well written and exceptionally clear. 

Here's a 1989 oral interview of Manabe by Spencer Weart of the American Institute of Physics.

And, let's say it: Manabe and Klaus Hasselmann, who also built climate models, were right in their predictions -- they correctly predicted the Earth's response to increasing carbon dioxide in the atmosphere. Here's a nice evaluation of Manabe and Wetherald's 1967 result: they predicted a CO2 climate sensitivity, when CO2 goes from 300 ppm to 600 ppm, of 2.4°C, which is in today's range of 1.5-4.5°C.  just shy of AR6's range of 2.5 - 4.5°C.

And, as that blog post notes, they made their prediction in 1967, at a time when the Earth's surface temperature was in a slight 20+ year cooling period. But they got a bit lucky -- if that cooling period was caused by atmospheric aerosols -- air pollution from vehicles, mostly -- they couldn't have known it would be cleaned up by the proliferation of clean air laws in the 1970s in the US and Europe. 

I don't know as much about the work of Klaus Hasselmann and Giorgio Parisi, but am looking forward to learning more today.

A very thoughtful Prize.

Monday, October 04, 2021

It Doesn't Matter if You Believe In Climate Change....

WaPo story here.

Polar Sea Ice Extent Updates

 Just thought I'd post the Arctic and Antarctic sea ice extents, through September 2021. These are the 12-month moving averages, so lag latest conditions a bit. It will be interesting to see where the Antarctic goes --  back on its old trend?