Katie Mack Profile picture
Cosmologist, writer, connoisseur of cosmic catastrophes. @TEDFellow. Author: "The End of Everything (Astrophysically Speaking)". Personal account. She/her. Dr.
Jeffrey Rubinoff Profile picture 1 subscribed
Sep 21, 2018 14 tweets 2 min read
I want to make you dizzy I want to make you look up into the sky and comprehend, maybe for the first time, the darkness that lies beyond the evanescent wisp of the atmosphere, the endless depths of the cosmos, a desolation by degrees
Sep 7, 2018 5 tweets 2 min read
In The Hitchhiker's Guide to the Galaxy, Douglas Adams wrote that the trick to flying is to "throw yourself at the ground and miss." It turns out that from a physics viewpoint, this is very nearly correct. The trick is to actually throw yourself really fast *sideways* such that when you fall, you miss, and keep falling, and keep missing.
Sep 1, 2018 5 tweets 1 min read
It is Friday night and I feel the need to tell you a thing about being stardust Yes, you are made of stars. Yes, you, in particular.


All that carbon, oxygen, nitrogen, etc — that was all made in stars. Most of your body is made of that stuff: atoms that a star forged inside itself or at the moment of its unimaginably violent death.
Aug 21, 2018 6 tweets 2 min read
I was contacted by a journalist about this today because someone in Turkey with almost a million followers tweeted out a version of this meme that somehow manages to be even more wrong The confusion evidently comes from a New Scientist article that makes somewhat misleading claims based on a 2007 study whose speculative results have been disputed in the literature several times since then. And then someone stuck an image of a dark nebula to it, for fun.
Jul 26, 2018 15 tweets 3 min read
Friends, we need to talk about The Future. It is no longer acceptable to complain about not having jetpacks and flying cars. Old TV shows have created a generation of people doing sci-fi-future envy wrong. Thread begins here. JETPACKS exist. They’ve been around for decades. No one uses them because they are expensive, inefficient, extremely loud, and fantastically dangerous. Want to get somewhere fast? In many cities you can now walk down the street and rent an electric scooter with your phone. Enjoy.
May 11, 2018 13 tweets 3 min read
I want to tell you a short story about #DarkMatter and how the search for it sometimes leads us to beautiful and surprising things. (thread) One of the ways we look for (invisible) dark matter is through "self-annihilation." Idea is: when two dark matter particles love each other very much, they might (with some small probability) annihilate and create stuff we can see.
Mar 20, 2018 9 tweets 2 min read
Just finished reading through this: arxiv.org/abs/1707.07702 — Stephen Hawking’s last paper, which explores some questions about the beginning of the Universe Beware of the press coverage, though. Most of the articles I’ve seen claim the paper says things it definitely does not say. (It is, to be fair, extremely technical.)
Dec 12, 2017 9 tweets 1 min read
One downside of being an astrophysicist is hearing lyrics like "I am attracted to you like the Sun to the Moon" & involuntarily twitching I mean yes okay the Sun, having mass, is attracted to the Moon, because it also has mass, but man it's a REALLY weak pull
Oct 22, 2017 5 tweets 1 min read
Nice (somewhat technical) discussion here on dark matter and gravitational waves Suuuper simplified:
- some theories mess w gravity to try to kill dark matter
- in those, grav waves & light respond to gravity differently…
Sep 15, 2017 7 tweets 3 min read
What does @CassiniSaturn mean to me? It's more than an instrument for observations. It's a traveller, visiting another place, an alien world Very few of us humans will ever leave Earth. But missions like @CassiniSaturn give us a taste of that freedom, & let us reach out & explore.