New Era of Astronomy. Kilonova Observed. New Gravitational Wave Discovery

[Art Blade]

Essentially, Albert Einstein predicted (almost exactly 100 years ago) that two orbiting objects would emit gravitational waves (at the speed of light) as they spiralled in. Astrophysicists predicted that if two neutron stars collided, a gamma ray burst would follow. Additionally, a cascade of light would be emitted throughout the whole electromagnetic spectrum. Also, heavy elements (anything heavier than iron) such as gold and platinum would be formed.

All those predictions were confirmed true, in just one day, a few hours, actually.

- The explosion following a neutron star merger causes a flash 1,000 times brighter than a regular nova, hence kilonova.

- A neutron star is a compact object that remains after a massive star (up to 20 sun masses) collapsed, it has got a radius of only about 10-15 km but is around one to two sun masses heavy.

- A gamma ray burst, or GRB, is unbelievably powerful, it equals 50 billion billion billion hydrogen bombs  

There is more. They now got a proper value to the Hubble Constant (expansion of the universe), 70km per second per megaparsec. Before, they could only guess rather than measure the speed, using red-shift. Now that they had several different types of data coming in from the same source, they could actually measure all that and then properly calculate the speed at which the universe is expanding. This is crazy






This is brand new.. (discovered in the Galaxy NGC 4993 on August 17, 2017, yet only now published) Regarding the vid below, skip to the about 14 minutes mark when the actual stream started.

[mandru]

It's all very fascinating. 

What a time to be alive.

[Dweller_Benthos]

It is very interesting. Just goes to show how smart Einstein was, 100 years ago, when most people were still getting around by horse, he was thinking up stuff like this.

[PZ]

Makes one wonder what the next 100 years will bring 

[fragger]

Thanks for posting, Art I have been keeping abreast of this development. It's awesome, in the most literal sense of the word. The forces at w0#k in the cosmos are mind-boggling. Fortunately for us, there's nothing like that going on in our quiet little galactic neighbourhood. You wouldn't want to be anywhere near something like this.

The light from this event has only just reached us after travelling through space for 130 million years, from a galaxy beyond our own. Dinosaurs were still in existence on Earth when the event originally took place, but we're only just seeing it now.

And we almost missed it. One of the key components that helped made the initial discovery (I can't recall whether it was on NASA's side or the ESO's - maybe it's mentioned in the longer video Art linked to, which I don't have time to watch right now) was going to be taken down the very next day for maintenance or upgrading or something, and they caught this event just in the nick of time, as it were.

We live in fascinating times indeed. We're seeing cosmic evolution in action. The elements produced by these cataclysmic events and then released into the interstellar medium are ultimately the ones that make up - well, everything, including our bodies, the food we eat, the clothes we wear, the cars we drive, the houses we dwell in and the planet we live on. It's an incredible process, unbelievably violent, but necessary for life to eventually come into being. Life that includes creatures like us, which have evolved with the cerebral cortex and opposable thumbs necessary to enable us to develop the technology to study and analyze the events that brought us into existence.

One of my favourite Einstein quotes is "A physicist is an atom's way of learning about atoms".

It's an exciting time to be an astronomy nerd 

[Art Blade]

you're very welcome

It was also luck that we caught the event as it is because if it had happened before those gravitational wave detectors LIGO (based in Louisiana and Washington state, USA) and VIRGO (based in Italy, Europe) were installed, it would have been "just another GRB" and we would have had to wait perhaps 15 or more years to catch the next event. And we were lucky because it happened "only" 130 million light years away from us which is almost in our immediate neighbourhood (by galactic standards ) so we had a pretty good view. Then again, they're only just beginning to improve calibration of said detectors. The next upgrade or calibration will allow them to get twice as good a result, depending on how you look at it, even eight times as good. Plus now we'll have to get used to multiple different input devices ("multi messenger astronomy") rather than just peeking through some polished lenses in a tube. It is going to open our eyes, I think

And indeed, you don't want to be near an event like that. The flash can be seen on the other end of the universe, so powerful. Planets get stripped of their atmosphere which will just get blown out into the universe and whatever life there might have been in reach of the blast, gets toasted beyond recognition. So, who knows how many life forms got lit up and instantly went extinct in the process of supernovae let alone kilonovae. And here we are, alive and kicking

[LowPolyOWG]

Wikipedia article

The space is fascinating. I had numerous books covering science/space as a child

Tabby's star abnormal lighting behaviour isn't something astronomers have observed before. Some suggests it could be aliens harvesting energy, others suggest a Saturn-like exoplanet orbiting around it. Dust clouds might also explain this, the star has probably destroyed some planets or trapped comets/asteroids in its gravity field.

[mandru]

I was pleased to learn from that dry and longish 3rd video (a glorified nerd circle, self-back-slapping ceremony ) that one of my favorite names in the field Kip Thorne was mentioned with a couple other guys who were going to receive a Nobel Peace Prize for astrophysics.