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Things from Today:
Eclipses - This was a hot topic of discussion, given the very exciting 90% coverage partial solar eclipse we were all excited to witness on August 12th. I delivered a micro-lecture on the eclipse at the end of the pier, which Cllr Matt Dent was kind enough to record, and caption (which is enormously helpful, given the technical issues with the microphone!) - thank you, Matt!
No doubt we will be treated to a few eclipse photos on Sunday August 16th, by some of our talented Astrophotographer attendees!What if the Sun suddenly turned into a Black Hole? - This question has a suprising answer (albeit... surprising in how relatively un-exciting it is!).
The maths that governs the behaviour of black holes comes to us from Albert Einstein (outlined in his 1915 theory of gravity, called 'General Relativity'). One of the central mathematical results in general relativity (called Birkhoff's Theorem) tells us that the force of gravity felt at a fixed distance from a star, and at the same fixed distance from a black hole of the same mass; should be identical.
This means, if our Sun did suddenly turn into a black hole, the Earth and all of the other planets in our solar system would continue in their orbits pretty much as before.
Often, people have this idea of black holes as monstrous eating machines, or cosmic hoovers, sucking in all around them (which, is certainly true if you get too close!..). But in reality, the gravitational pull they exert plays by the same rules as any other object - the closer you get, the stronger it is. But if you are at a reasonable distance away, you can fall into orbit much like the Earth orbiting around the sun.
Now.. that is not to say we wouldn't notice any difference... Black holes don't give off light or heat anywhere near the same way a star does; so the Earth would very quickly become uninhabitable due to the extreme drop in temperature.
Technical side note: What I am describing here, based off Birkhoff's theorem is only approximately true. Physicists have managed to determine, using a remarkably light touch set of tools that form part of a branch of theoretical physics called 'effective field theory', that Birkhoff's theorem would not hold true in a Quantum Theory of Gravity. The gravitational pull of a black hole actually is ever so slightly different to the pull of a star - but this difference is only noticeable at very close range to the black hole.
This work is quite recent, and you can read more about it here.Launch of the NASA Roman Telescope - We spoke about the NASA Roman Space Telescope, due to launch on August 30th from the Kennedy Space Center.
This telescope is scientifically exciting for many reasons - one being the enormous field of view it can capture, compared with the Hubble space telescope. Roman will be able to capture images at least 100 times larger than Hubble.
This telescope is named for Nancy Grace Roman, who was a pioneering astronomer, and NASA executive.
There is a great explainer video here, giving a lot of detail on the scientific discoveries Roman will be pursuing.
Extra Reading:
[Article] NASA Webb Finds Strongest Evidence Yet for ‘Black Hole Stars’ - (NASA Webb Mission Team)
[Article] JWST spots a bizarre “black hole star” 100 billion times brighter than a star - Jennifer Chu (Science Daily)
[Book] The Possibility of Life: Searching for Kinship in the Cosmos - Jaime Green (Duckworth Publishers)
Extra Watching / Listening:
[Video] Tackling the Biggest Unsolved Problems in Math with 3Blue1Brown - Grant Sanderson (StarTalk)
[Video] The new telescope 100x better than Hubble - (Digital Astronaut)
Homework
This 'homework' is recurring, and one I like to set my own students (and try to stick to myself!):
Learn something new everyday.
Share what you know with someone else.
Look at the world and "think like a Martian".
If you learn something interesting, I would love to hear about it! Tell me about it next time or drop me an email!
spacetime-sundays@science-on-sea.com
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