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5 Mar, 5 tweets, 4 min read
This is an amazing optical illusion — caused by atmospheric conditions over the water bending light rays to make it look like the ship is above it. This video has a nice explanation (especially the bit starting around 1:20) . #FataMorgana
The proper term for this is “superior mirage” or “superior looming mirage” but I have seen the term “fata morgana” used for a similar phenomenon also caused by weird kinds of light bending over the ocean.
More on superior mirages from @iansample. theguardian.com/science/2021/m…

Rather than "optical illusion" it might be better to call this an "optics illusion." Your brain is processing visual information correctly, it's just that the light deflection makes that information unreliable!
There's an interesting discussion going on about whether this is REALLY a superior mirage or an inferior mirage or false horizon effect. I think it's hard to tell from the image, but see metabunk.org/threads/debunk… & animations.physics.unsw.edu.au/jw/light/mirag… via @MickWest & @Rainmaker1973. #Optics
I think the main lesson here is that you DEFINITELY cannot trust the details of what you see at a distance if you don’t know the thermal properties of the air in between. Because it can move the light rays around in unexpected ways and distort/displace images. #Optics

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More from @AstroKatie

Katie Mack Profile picture
4 Mar
Here’s a long-ish excerpt from my book where I talk about THE BIG RIP, one possibility for the end of the universe. (More likely is a Heat Death, caused by endless accelerated expansion, which *doesn’t* rip things apart. But a Big Rip would be fun too.) americanscientist.org/article/tearin…
I just saw a clip of Neil deGrasse Tyson on the Late Show saying that the Big Rip is likely coming and that it’s the necessary result of endless accelerated expansion, neither of which is true! So, see above for clarification.
If you’re interested in reading about what cosmologists are discovering now about how the universe might end, check out my book, “The End of Everything (Astrophysically Speaking)”! It’s accessible and comprehensive and has lots of funny footnotes astrokatie.com/book
Read 4 tweets
Katie Mack Profile picture
19 Feb
A thing a lot of people don't seem to be aware of is that the proportion of astronomers who believe there is alien life of some sort in the universe is almost 100%. It's just the proportion who think they've *dropped by* that's almost 0.
I had a radio interview recently where the host started out all challenging saying "It's UNTHINKABLE there isn't other life out there in the cosmos!" and I was like, "yeah, pretty much" and I think he was not really prepared for that
What we know is that we find life in just about every environment we look for it on Earth, wherever there's some amount of liquid water -- sometimes even just ice. And we know there is water on other worlds. And there are a LOT of other worlds. So: life seems likely to be common!
Read 4 tweets
Katie Mack Profile picture
7 Feb
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.…)
Read 4 tweets
Katie Mack Profile picture
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
Katie Mack Profile picture
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
Katie Mack Profile picture
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

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