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Friesiansam

Well-known member
I think you both misunderstand. Matter can and does bend space, but without matter to bend it, and in particular on larger scales, space is flat insofar as we can tell. There have been pieces in The Sky at Night magazine recently.

(FWIW, I did physics and astrophysics to degree level, though freely confess I didn't finish - but I have kept up to date. Last year I bumped into someone from my school who went to the same university and did the same degree. He teaches physics and has worked at several large telescopes (even has an asteroid named after him) - my ego was plumped up by being able to comfortably converse at the same level, and by the fact that my understanding of orbital mechanics and why the Lagrangian points are stable was better than his. So it wasn't all wasted.)
I have an interest in physics and astrophysics, that dates from when I was still at primary school, but not at degree level...
 
I have an interest in physics and astrophysics, that dates from when I was still at primary school, but not at degree level...
Having re-read my post it feels a bit like trying to pull rank - not what I intended, and certainly doesn't mean I'm automatically right on such things - just means I've probably read as much as I need in order to know that I still feel baffled by much of physics!
 
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There is a piece on Andy Wallace in this week's Autocar. He got a slightly non-standard Bugatti Chiron to just under 305 mph. The valve caps on the tyres weigh a couple of grams, but at that speed the centrifugal force means even these 'weigh' 7.5kg - about as much as a typical Jack Russell.

Gives an idea of the sheer forces involved.
 
I was reading a short piece about neutron stars the other day. These can form during the death of stars not large enough to form black holes, but are still startlingly dense. Apparently a sugar cube's worth of neutron star matter weighs as much as the entire human race.

I seem to recall reading a while back that if you could stand on top of a wall on a neutron star (neither standing nor the wall being possible, but there you go), if you jumped off (again not possible) you'd be travelling at a million miles per hour by the time you hit the surface.
 

Friesiansam

Well-known member
I was reading a short piece about neutron stars the other day. These can form during the death of stars not large enough to form black holes, but are still startlingly dense. Apparently a sugar cube's worth of neutron star matter weighs as much as the entire human race.

I seem to recall reading a while back that if you could stand on top of a wall on a neutron star (neither standing nor the wall being possible, but there you go), if you jumped off (again not possible) you'd be travelling at a million miles per hour by the time you hit the surface.
I think many people don't appreciate just how much of normal matter, is actually empty space, even though it may appear solid.
 
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Did you know limestone caves in Devon was responsible for a well-known saying.

With around 50 miners in close proximity banging lumps of limestone, the echoing noise for hours everyday made the miners death....

That's where the saying: 'Stone death' comes from.
 
Fascinating piece about the Earth's core and structure in this month's Science Focus:

- The cooling of the core adds 8,000 tons of iron to the solid core every second. This works out as the same as adding the mass of every human alive every year. But this only increases the core's diameter by about 2mm a year.

- As the outer core solidifies, our magnetic field will weaken and then cease to exist. Probably making life here impossible, but that's estimated at 91Bn years away - the sun will long have toasted us by then.

- The magnetic field is not even though, because of varying degrees of convection in the outer core. The area of lowest strength is called the South Atlantic Anomaly, and the field's weakness has damaged satellites and ISS astronauts cannot perform spacewalks when they pass through it.
 
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