Watching the snow fall outside and thinking about terminal velocity, and how much less peaceful this whole scene would look without air resistance. ❄️💥
Terminal velocity is the final speed something reaches when falling through a fluid (like air). The force of gravity accelerates the thing, and air resistance slows it down (in proportion to the square of the speed), so at some point those things balance and it stops speeding up.
Terminal velocity for a raindrop is around 9 meters/second. For a snowflake it’s generally closer to 2 meters/second, depending on the size and fluffiness of the flake. (Some formulae here hyperphysics.phy-astr.gsu.edu/hbase/airfri2.…)
For some reason the image has come into my head of what it would look like if snow just kept accelerating. A flake formed in a cloud 5000 feet up would hit the surface at half the speed of sound. A gentle flurry would be carnage. Snow angels would be a different color.

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More from @AstroKatie

1 Feb
Reporting on non-mainstream ideas in science is often skewed on either side, presenting them as either rare/revolutionary or totally suppressed.

In practice, there are a ton of people working on ideas their colleagues look at & say "eh, a bit niche" that might/might not pan out.
We don't invest en masse in the fringe ideas unless they pass enough rigorous tests to become the new consensus, but no one is saying "you can't publish on that." The vast majority of papers on ALL topics are ignored; the more extraordinary the claim, the more evidence it needs.
Not sure why I’m going on about this so much lately. I just think it’s important for people to know that in between all the big flashy results there are a bunch of us just chugging along trying all different things (and getting excited or not) and that’s good and normal science.
Read 5 tweets
30 Jan
Love it when people come into my mentions to tell me their personal criticisms of modern cosmology theory like I’m soliciting product reviews and will relay their complaints to the physics manager.
I’m sorry you find the current cosmological consensus around dark energy to be aesthetically unpleasing but telling me that is not going to upend the paradigm and replace it with one you like better.
I promise we have good reasons for favoring the theories we do, and I do try to explain those reasons from time to time! The reasons are not “we are too lazy to come up with something else” or even “we accept the first idea we find and stick with it despite its obvious problems.”
Read 4 tweets
12 Dec 20
Vaccines are combat training for your immune system. They show it what to expect from a virus/bacteria so your cells can build a better defense when the actual pathogen arrives.
Usually, a vaccine gives your immune system dead or weakened pathogens so it can mount a specialized defense. Say an invading army is coming and you capture some soldiers and their weapons. You'll be in a much better position to repel the invasion than if caught by surprise!
mRNA vaccines, like Moderna & Pfizer/BioNTech's, work differently. They give your cells the blueprints for a piece of the virus, so your cells can build that piece (which, on its own, can't hurt you), study it, & be ready to attack it & the virus it's attached to when it shows up
Read 5 tweets
9 Dec 20
SpaceX #Starship launch attempt scheduled to start in five minutes or so... #SN8
This is the rescheduled launch attempt after the last-second abort yesterday:
Read 6 tweets
9 Dec 20
If you give my book as a gift you can write on the card "I will love you until the end of the universe"! It's really a very romantic kind of present!!
"Unlike the Higgs vacuum, my love for you will never decay"
"The cosmos may succumb to a Heat Death due to the second law of thermodynamics, but the first law of MY HEART is that I love you"
Read 6 tweets
8 Dec 20
SpaceX is about to do a high-altitude test flight of its Starship prototype, in about two minutes theverge.com/2020/12/8/2216… spacex.com/vehicles/stars…
Or... not. Abort. Alas.
The #Starship prototype did not launch but it ALSO did not explode so I think this is a "successful failure" situation and the data will be helpful to the engineers as they set up for the next try. #SN8
Read 4 tweets

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