Corey S. Powell Profile picture
Opening minds @openmind_mag. Unfolding research @AmSciMag. Casting pods with @BillNye. Not an AI. I'm also on Mastodon: @coreyspowell@mastodon.social
May 8 4 tweets 3 min read
I was a NASA intern in the '80s when I heard that astronomers had discovered a mysterious disk around the nearby star Fomalhaut.
Now JWST has revealed exactly what they are: three enormous, dusty asteroid belts around another star!
webbtelescope.org/contents/news-… ImageImage In the 18th century, Swedenborg, Kant & Laplace proposed that planets form in discs around stars. It took more than two centuries to see they were correct! But now we can observe discs, asteroids, comets, and even colliding planets around other stars.
en.wikipedia.org/wiki/Nebular_h… Image
Mar 2 4 tweets 3 min read
A new seismic study shows that Earth has five inner layers, not four as long believed. Inside Earth's inner core is an *inner-inner* core, a ball of white hot iron 1300 km (800 miles) wide. science.anu.edu.au/news-events/ne… #Geology #earthquakes Schematic showing the newly confirmed inner-inner core of th Researchers at Australian National University developed a clever way to sense seismic waves reverberating inside the Earth. Those echoes made it possible for them to sense the growing metallic seed at the center of our planet. nature.com/articles/s4146… #Perspective Diagram of the seismic network used to study Earth's complex
Jan 24 7 tweets 5 min read
If you saw this headline, or one like it, you might reasonably have thought the world has gone mad. The inside of the Earth is spinning backwards?
*But that is not at all what the actual research says.*
[a short thread] #RealityCheck Misleading tweet headline f... Key point: Earth's core rotates at almost exactly the same rate as the rest of the planet. Did in the past, still does so now. It rotates at the same speed to within 0.001%!
But even the research paper is confusing on that point: #RealityCheck
nature.com/articles/s4156… Schematic of Earth's interi...
Dec 13, 2022 9 tweets 8 min read
You're about to hear a lot about #NuclearFusion. I've followed the field for years & can offer context. Top line:
- NIF's "breakeven" does not generate more power than it consumes
- NIF is not a model for a commercial fusion reactor
- This news is a big deal all the same. 1/n Target positioners for the National Ignition Facility. Fusion researchers measure fusion output in "Q," the ratio of power produced to power needed to maintain the fusion plasma. NIF has exceeded Q=1.
Breakeven, right? Er, the accounting is not so simple, as Charles Seife explains. 2/n theatlantic.com/technology/arc… #fusion #NIF
Aug 1, 2022 7 tweets 3 min read
Twitter is full of "wonder science" accounts, many of them full of stolen images & misinformation. The recent viral tweet about the alleged void in space offers a good case study in how to spot the fakes. 1/5 Test #1: Who is sending the tweet? Reputable researchers, journalists, and institutions identify themselves. If the account is anonymous and contains no information, you should be suspicious. 2/5
Feb 4, 2022 13 tweets 7 min read
The true colors of the solar system, a short thread. * First, let's start with the Sun. Can we all agree it's white to the eye?

* inspired by James O’Donoghue & Marina Koren, with some color corrections by me. Mercury is so gray that it's tough to tell whether you are seeing pictures of it in color or black-and-white. This one is true color, seriously. blogs.agu.org/wildwildscienc…
Jan 7, 2022 4 tweets 2 min read
Remember the "mystery hut" spotted by China's Yutu-2 rover on the far side of the Moon? Now we've seen it up close. Behold...a Moon rock. mp.weixin.qq.com/s/VgtehRidYL8-… Reminder: When you apply a lot of imagination to an image at the very edge of resolution, you're going to "see" all kinds of strange things. The Face on Mars was a classic of this genre.
Mar 5, 2020 9 tweets 2 min read
I see versions of this nonsense claim all the time. This one went hugely viral. So let's dig into the actual numbers, cars versus volcanoes. (1/x) Human activities released 33 billion tons of CO2 in 2019. About 16% of that, or 5 billion tons, is associated with road transportation. iea.org/articles/globa…
Jun 14, 2019 6 tweets 3 min read
30 years ago, nobody knew for sure whether there were ANY planets around other stars. Today the number of confirmed planets just passed 4,000--and the variety out there is staggering. [a short thread] A sweeping new paper (341 pages!) analyzes 426 nearby red dwarf stars. They seem to average at least 3 planets each, which translates to more than a trillion planets in the Milky Way, over 100 billion of them potentially habitable. arxiv.org/abs/1906.04644