The night sky

[andyBeaker]

wow.

Last night we spent the hours between 22.00 and 04.15 in the company of a stargazer with a decent telescope who knew their stuff in the pitch black of South Wales.

Absolutely incredible experience for anyone with any imagination.

All enhanced by numerous bottles of Cava and tubes of Pringles.

So, is the sky infinite.......?

 

[Jaws]

While at a rally weekend before last, we was treated to a particularly long pass by the ISS
Its trajectory brought it directly overhead so it was in site for maybe 2 minutes or more

Like the man said, ' Space, the final frontier' .. I used to give myself headaches trying to work out where and if it ends.. If it ends there has GOT to be something beyond that point, so it is not ended, but if it does not end, perhaps it is a mobius loop in which case what is beyond the confines of said loop..... AAARRGHHHHHHHHHHHHHHHH

 

[Oldandbald]

Here you go guys - this explains it all pretty clearly!

Is the universe infinite, or finite? How big is the universe?
We know that the universe is expanding because, with some nearby exceptions, almost every galaxy in the universe is moving away from us and from one another. Not only that, but very distant galaxies appear to be receding even more quickly, evidence that the universe is expanding at an increasing rate.

Observations of various times in the universe suggest that, for the first several billion years, the universe’s expansion slowed — but then roughly 8 billion years ago, expansion began accelerating. If the acceleration continues (which seems likely), the universe will never slow its expansion or re-collapse. This corresponds to the idea of a “flat” universe, which is currently the most accepted model.

But a spatially flat universe can be characteristic of either a finite or an infinite universe. When we say that space is “flat,” we mean it obeys Euclidean geometry: parallel lines never intersect, and the angles of a triangle always add up to 180 degrees. We can imagine the universe in two dimensions as a plane, which is flat and infinite (like an infinite piece of paper). But we can also imagine taking that paper and rolling it into a cylinder, then rolling it again into a torus (doughnut shape). The surface of the torus is spatially flat, like the piece of paper, but finite. However, with expansion, it is possible that even if the universe just has a very large volume now, it will reach infinite volume in the infinite future.

Now where are my bloody tablets...

 

[andyBeaker]

For all we know we might be the equivalent of a speck of mud in a massive pond.

I didn't appreciate how many satellites passed overhead - I knew about The Clarke Belt but was amazed at how many other bits were floating about.

 

[Jaws]

This is worth a read..

https://www.popsci.com/space-junk-debris-falls#page-3

Part that really got me thinking ( about quantum effect on solid objects ) was this

QUOTE:

According to The Aerospace Corporation, one of the few organizations that tracks space debris, an on-orbit collision would look “more like an explosion of each object, as if they passed through each other and exploded on the other side.” Orbiting objects are moving faster than shockwaves can go, so when two of them collide they essentially shoot through each other and then feel the impact from the shockwaves.

 

[andyBeaker]

This is worth a read..

https://www.popsci.com/space-junk-debris-falls#page-3

Part that really got me thinking ( about quantum effect on solid objects ) was this

QUOTE:

According to The Aerospace Corporation, one of the few organizations that tracks space debris, an on-orbit collision would look “more like an explosion of each object, as if they passed through each other and exploded on the other side.” Orbiting objects are moving faster than shockwaves can go, so when two of them collide they essentially shoot through each other and then feel the impact from the shockwaves.

I am reading Endurance at the moment - by the chap that spent a year on ISS - there is a rather wry section that talks about the procedure that was used when the real possibility of a collision with a piece of space junk had been detected - basically closing all the hatches, which he thought might not achieve much with a closing speed9f 30,000mph +.

Excellent read by the way, recommended.

 

[derek kelly]

I am reading Endurance at the moment.

Multitasking, reading whilst posting crap on here.