Re: Night Sky : Thu May 29, 2014 10:23 am  

If the Moon were only 1 pixel big .... (Gonna need your Right-arrow key)

If the Moon were only 1 pixel big .... (Gonna need your Right-arrow key)

Re: Night Sky : Wed Jul 16, 2014 11:47 am  

11 November. that's the date when ESA (European Space Agency)'s probe Rosetta is going to send a lander to touch down on a comet (67P/Churyumov-Gerasimenko) And as it approaches, latest images show a unique object- the comet is actually two lumps, seemingly joined by a bridge. Where to land? http://www.bbc.co.uk/news/science-environment-27110882

11 November. that's the date when ESA (European Space Agency)'s probe Rosetta is going to send a lander to touch down on a comet (67P/Churyumov-Gerasimenko) And as it approaches, latest images show a unique object- the comet is actually two lumps, seemingly joined by a bridge. Where to land? http://www.bbc.co.uk/news/science-environment-27110882

Re: Night Sky : Wed Aug 06, 2014 1:38 pm  

Rosetta spacecraft has just tweeted that it's arrived at the comet.



It will now keep pace with the comet as it travels into and back around the Sun, and in November a small landing craft will be sent to land on the comet itself, which is roughly 3 or 4 miles long.

Re: Night Sky : Fri Sep 05, 2014 4:04 pm  

About 6pm Sunday there's a near-miss by an asteroid - but it is 100% certain to miss if only by 22,000 miles. Was only discovered on Sep 1 as it is so dark, and so shows the value of better resources aimed at spotting potential hazards. Unlike recent ones, you'll not see this one without a big telescope. It's a similar size to the one that blew up over Russia last year, which nobody had spotted. article

About 6pm Sunday there's a near-miss by an asteroid - but it is 100% certain to miss if only by 22,000 miles. Was only discovered on Sep 1 as it is so dark, and so shows the value of better resources aimed at spotting potential hazards. Unlike recent ones, you'll not see this one without a big telescope. It's a similar size to the one that blew up over Russia last year, which nobody had spotted. article

Re: Night Sky : Sun Sep 07, 2014 9:38 pm  

Thanks for keeping this updated bud. Much appreciated.

Re: Night Sky : Mon Sep 08, 2014 1:12 pm  

So here's an interesting discovery: A fairly recent supernova (1987A) was observed at a fairly early stage (they have for a long time had 'scopes watching out for them across the sky). We can also now detect neutrinos. (Neutrino: miniscule particle, generated by big fekkoff explosions (like supernovae); travels at almost speed of light, goes straight through planets as if there is nothing there; about a quarter of a million pass through every square inch of your body every second of your life). So, the telescope scientists asked the neutrino detector scientists if they had picked up the burst of neutrinos from the new supernova. Indeed they had. Three hours before the supernova light reached the telescopes. Explanation? ? ? ? (answer below, in case you want to try to figure it out before reading!) ________________________________________________________________________ 1987A remnant 18 years after the explosion (which actually happened about 170,000 years ago, but was still big enough to be visible with the naked eye) Well, the explosion starts in the centre of the star and when the big fekkoff bang happens, all the stuff in the star that explodes, explodes; the light from the explosion is in the form of photons. These bounce around amongst all the rest of the exploding matter, and don't set off across the universe until they escape from the explosion. Which took them in this case around 3 hours. Whereas the neutrinos, (which = most of the energy release) once released, aren't stopped by anything, so just immediately escaped and set off across space, leaving the light photons scrambling about trying to get out. So now the boffins have set up the SuperNova Early Warning System (SNEWS) to get advance neutrino warning of any nearby Milky Way supernovae. I also learned while reading this a bit about the light from the sun; everything you see (artificial light excepted) is photons from the Sun hitting your optic nerve, and it set off about 8 minutes ago from the surface of the Sun. But what i didn't know was that these photons, which all get generated in the centre of the Sun during the fusion process, actually spend millions of years trapped and bouncing round inside the sun, before they eventually reach the surface and escape. So whenever you look around outside, what you are experiencing is gazillions of photons aged millions of years, that happen to end their existence in the back of your eyeball and their energy converted by your own inbuilt photon detectors into a signal into your brain.

So here's an interesting discovery: A fairly recent supernova (1987A) was observed at a fairly early stage (they have for a long time had 'scopes watching out for them across the sky). We can also now detect neutrinos. (Neutrino: miniscule particle, generated by big fekkoff explosions (like supernovae); travels at almost speed of light, goes straight through planets as if there is nothing there; about a quarter of a million pass through every square inch of your body every second of your life). So, the telescope scientists asked the neutrino detector scientists if they had picked up the burst of neutrinos from the new supernova. Indeed they had. Three hours before the supernova light reached the telescopes. Explanation? ? ? ? (answer below, in case you want to try to figure it out before reading!) ________________________________________________________________________ 1987A remnant 18 years after the explosion (which actually happened about 170,000 years ago, but was still big enough to be visible with the naked eye) Well, the explosion starts in the centre of the star and when the big fekkoff bang happens, all the stuff in the star that explodes, explodes; the light from the explosion is in the form of photons. These bounce around amongst all the rest of the exploding matter, and don't set off across the universe until they escape from the explosion. Which took them in this case around 3 hours. Whereas the neutrinos, (which = most of the energy release) once released, aren't stopped by anything, so just immediately escaped and set off across space, leaving the light photons scrambling about trying to get out. So now the boffins have set up the SuperNova Early Warning System (SNEWS) to get advance neutrino warning of any nearby Milky Way supernovae. I also learned while reading this a bit about the light from the sun; everything you see (artificial light excepted) is photons from the Sun hitting your optic nerve, and it set off about 8 minutes ago from the surface of the Sun. But what i didn't know was that these photons, which all get generated in the centre of the Sun during the fusion process, actually spend millions of years trapped and bouncing round inside the sun, before they eventually reach the surface and escape. So whenever you look around outside, what you are experiencing is gazillions of photons aged millions of years, that happen to end their existence in the back of your eyeball and their energy converted by your own inbuilt photon detectors into a signal into your brain.

Re: Night Sky : Mon Sep 08, 2014 1:20 pm  

Stephen Hawking - God particle may wipe out the universe

Stephen Hawking - God particle may wipe out the universe

Re: Night Sky : Mon Sep 08, 2014 2:40 pm  

I've been watching Cosmos quite a bit and one of the things that puzzles me is about the Big Bang. How do we know for sure that the Big Bang wasn't just another star explosion and that beyond what we can currently see there isn't even more stars and galaxies? I understand how mathematically there are theories that matches current thinking to empirical evidence, however given that we cannot see further into the universe how can we be so sure? Found this link about the maths and theory bits. https://answers.yahoo.com/question/inde ... 246AAXzK6X

I've been watching Cosmos quite a bit and one of the things that puzzles me is about the Big Bang. How do we know for sure that the Big Bang wasn't just another star explosion and that beyond what we can currently see there isn't even more stars and galaxies? I understand how mathematically there are theories that matches current thinking to empirical evidence, however given that we cannot see further into the universe how can we be so sure? Found this link about the maths and theory bits. https://answers.yahoo.com/question/inde ... 246AAXzK6X

Re: Night Sky : Tue Sep 09, 2014 3:36 am  

We don't know anything about the Big Bang for sure, and it's possible we never will, as beyond a certain point, there was no light, so there is a limit to how far back in time telescopes can see. This occurs at about 380,000 years post-big bang and is known as the epoch of recombination. Before this, the universe was too hot for electrons and protons to pair up and form hydrogen and unbound electrons scatter light so until there was hydrogen, the universe was opaque. However the furthest back we have seen is maybe 700 million years after the Big Bang. So there is still plenty of time, literally. The James Webb telescope, due 2018, will be capable of extending our view back to 100 million years ABB. What it will see there is debatable, as whilst with difficulty we can discern young galaxies at these distances, if there were yrt no galaxies (current thinking is that unassociated but giant stars predated the formation of galaxies) these may be way too faint even for James Webb. Standard cosmology applies from the present time back to about 1/100 second after the Big Bang. Before then, particle physics and quantum cosmology describe the universe. There are scientific models where the Big Bang and thus the entire universe arose from simply a random quantum vacuum fluctuation in a particle field, and it is this process that Hawking is referring to in my above link re the possibility of the God particle destroying the Universe, a BB in reverse, if you like. The evidence for the Big bang as the beginning of what we know as time and space is therefore pretty overwhelming, but as for what happened to "cause" BB, or what existed "before", is really outside the realm of science, not because scientists give up, (most believe that "something" existed before BB) but because we can never know what happened "before" BB, as by definition there can never be anything to see or test or measure before anything existed. Personally I like the theory that there is a multiverse, think of it as each universe pictured as a membrane (or "brane") floating in the multiverse, and if one happens to touch another, this causes a BB. But there will (probably!) never be a scientific test of this as we by definition can't see outside "our" universe - as for us there can by definition be nothing else that exists outisde our universe, otherwise it wouldn't be a "universe". This of course doesn't EXCLUDE other universes but we can't reach them, as our own universe is infinite, and so doesn't have a border to cross to go outside it. I like the notion that just maybe The Great Attractor, a highly mysterious region in the Universe which is pulling our Milky Way - and tens of thousands of other galaxies - toward itself at 14 million miles per hour, is the spot where the event took place, but it's all a bit mad! I mean, the very notion (100% factual btw) that, apart from all other motions, I am heading that way at 14 million mph is more than enough to do my head in.

We don't know anything about the Big Bang for sure, and it's possible we never will, as beyond a certain point, there was no light, so there is a limit to how far back in time telescopes can see. This occurs at about 380,000 years post-big bang and is known as the epoch of recombination. Before this, the universe was too hot for electrons and protons to pair up and form hydrogen and unbound electrons scatter light so until there was hydrogen, the universe was opaque. However the furthest back we have seen is maybe 700 million years after the Big Bang. So there is still plenty of time, literally. The James Webb telescope, due 2018, will be capable of extending our view back to 100 million years ABB. What it will see there is debatable, as whilst with difficulty we can discern young galaxies at these distances, if there were yrt no galaxies (current thinking is that unassociated but giant stars predated the formation of galaxies) these may be way too faint even for James Webb. Standard cosmology applies from the present time back to about 1/100 second after the Big Bang. Before then, particle physics and quantum cosmology describe the universe. There are scientific models where the Big Bang and thus the entire universe arose from simply a random quantum vacuum fluctuation in a particle field, and it is this process that Hawking is referring to in my above link re the possibility of the God particle destroying the Universe, a BB in reverse, if you like. The evidence for the Big bang as the beginning of what we know as time and space is therefore pretty overwhelming, but as for what happened to "cause" BB, or what existed "before", is really outside the realm of science, not because scientists give up, (most believe that "something" existed before BB) but because we can never know what happened "before" BB, as by definition there can never be anything to see or test or measure before anything existed. Personally I like the theory that there is a multiverse, think of it as each universe pictured as a membrane (or "brane") floating in the multiverse, and if one happens to touch another, this causes a BB. But there will (probably!) never be a scientific test of this as we by definition can't see outside "our" universe - as for us there can by definition be nothing else that exists outisde our universe, otherwise it wouldn't be a "universe". This of course doesn't EXCLUDE other universes but we can't reach them, as our own universe is infinite, and so doesn't have a border to cross to go outside it. I like the notion that just maybe The Great Attractor, a highly mysterious region in the Universe which is pulling our Milky Way - and tens of thousands of other galaxies - toward itself at 14 million miles per hour, is the spot where the event took place, but it's all a bit mad! I mean, the very notion (100% factual btw) that, apart from all other motions, I am heading that way at 14 million mph is more than enough to do my head in.

Re: Night Sky : Sat Sep 13, 2014 2:46 am  

So today we learned that we all live in Laniakea!

What's that? It turns out our own galaxy, the Milky Way, is part of a supercluster of galaxies which has been named Lanikea

LANIAKEA


Mind-bogglingly, we are in the outskirts ofthis supercluster, whose extent has for the first time been carefully mapped using new techniques. Thed Laniakea Supercluster is 500 million light-years in diameter and contains the mass of 100 million billion Suns spread across 100,000 galaxies.

You just have to watch this amazing video animation that illustrates this and is truly awe-inspiring. And - by a strange coincidence - this video also includes graphics of the effect on the supercluster of the Great Attractor, which I just mentioned the other day. You can find it on some video tube or other under /rENyyRwxpHo

Welcome to Laniakea!