DoubleG
5716
This one was only picked up last weekend by amateur astronomer Gennadiy Borisov, who operates from Nauchnyi in Crimea, the peninsula that Russia seized from Ukraine in 2014.
On August 30, 2019, he used this telescope to discover the first known interstellar comet, 2I/Borisov, which is only the second interstellar object to have been observed.[6][11] … The discovery of 2I/Borisov by Gennadiy Borisov has been compared to the discovery of Pluto by Clyde Tombaugh.[8]
I feel like astronomy should drop the “amateur” label for some of these guys, degrees be damned
Dejin
5717
This is a fun interview with a Space Shuttle pilot conducted in one of the actual Shuttles sitting in the museum.
Actually, that’s a video of someone setting up a VCR c. 1982.
That is cool. That first video at 1:08; that is so beautiful.
So I was watcing a NOVA on the Big Bang and have a question that someone more astronomyish than me can hopefully answer. If BB is at location A (really, the earliest known galaxy created a few hundred million years after the BB) and we’re at location Z and moving away from A at less than the speed of light, how did we get to point Z before the light itself from the BB got to point Z?
I know that right after the BB was the Inflation which expanded the Universe faster than the speed of light, but it didn’t last long and only pushed the universe from atom-sized to basketball sized per the NOVA. So how is it that we can still see the earliest galaxy at point A when that light should have passed point Z long before we got to point Z?
dtolman
5722
Keep in mind that Point A and Point Z are identical.
The universe was all contained in Point A. The universe itself then began to expand. Picture a balloon - you paint two dots on the balloon - then blow it up as big as it can get. Same balloon - but its stretched out now over more surface area.
Those points did not move - but the space between them increased because of the expansion of the balloon.
Right now the space between points on the “balloon” (i’ve seen an expanding raisin loaf in an oven as another comparison) that is our universe is expanding faster than the speed of light. This was not always the case - the rate of the "balloon"s expansion is increasing.
We are in a unique moment where its easy to see photons from the beginning of the universe, that were on the far side of the balloon from us. Billions of years from now, that won’t be the case.
Ah, ok. I’m sure I’ve heard that before now that you mention it (the balloon and raison loaf analogies) and as I was posting that idea sort of popped into my head but didn’t quite gel til you answered. Thanks. Now I won’t be pondering this all day, hehe.
Enidigm
5724
Another thing is that inflation is an extremely abstract concept that lasts a tiny fraction of a second. So as hard as it is to conceive, the “point to grapefruit” happens during inflation faster than the speed of light. Basically (as I understand it) they’re trying to account for the uniformity of the Cosmic Microwave Background. And that’s understood to be a reflection that regions stopped “communicating” with one another.
Everyone always says things like “local universe” now - it’s assumed that there are objects of the same age somewhere outside of our field of view that we cannot “communicate” with. Dark Energy is causing the current universe to expand again. It’s supposed to be a “scalar field”; ie one variable, ie, like your pool of health or mana in a video game, its one number, and that it dominates because as things get further apart gravity is less able to keep things together.
vyshka
5725
My first thought when seeing the picture and the headline, was that that black silhouette looked like a boat. :)
Houngan
5726
Money quote:
We thus propose that stellar remnant black holes are the astrophysical origin of dark energy, explaining the onset of accelerating expansion at z ∼ 0.7.
From here, which is a proper scientific paper and thus a bit beyond me: https://iopscience.iop.org/article/10.3847/2041-8213/acb704
Via this article, which leans perhaps too hard the other direction: Black holes may be quietly generating the force that is tearing the universe apart, experts say | Salon.com
RichVR
5727
What has happened in space? TIL Globus. Article in link.
lostcawz
5728
Much like Jon Snow, we know nothing. . Well, not as much as we thought we did anyway.
Edit to add so you don’t have to hit link. Galaxies as large as are own from only 500 millions years after the Big Bang. Which wasn’t supposed to happen.
That’s so cool. I love mechanical doodads like this, all the precision gears and what not. Some serious ingenuity on display for sure.
Timex
5731
It’s weird when you think about the fact that any digital circuit or software can be represented mechanically, and indeed, they all were not too long ago.
For me, as a computer scientist, performing complex math in software is routine… but seeing some of the mechanical systems designed to perform complex math, like ballistics calculation machinery, is super cool, seeing the physical representation of things like differential equations.
Yep. Software is a way to do hands-on math without a bunch of machine tools.
Hardware is the original object oriented design paradigm.
vyshka
5734
I recently re-read The Dream Machine which early on talks a bit about the systems that were used for doing differential equations around the start of the second world war, and the work required to set them up to solve a problem.
One of the systems that has always fascinated me from early computing is mercury delay line memory.
