Stellar collision confirms theoretical predictions about the periodic table | Hacker News Reader

Stellar collision confirms theoretical predictions about the periodic table

nature.com

92 pointsrstoj59 comments

Whenever I read about neutron stars, they are always too far away (like millions of light years), so I did a quick search and found one closest to earth about 250 to 1000 light years and apparently it is above the plane of the milky way galaxy.

https://www.space.com/4247-astronomers-find-closest-neutron-...

I wish we could watch these neutron stars and black holes more closely, we know so little about the universe.

Making sure you don't miss this in that case: https://www.youtube.com/watch?v=Qt82NjSPAc8&disable_polymer=...

Thank you for the link, it's amazing how quickly it cooled down. I thought it would take hundreds of years for it to go from blue to red. But I guess since the merger of the neutron star resulted in the formation of blackhole, It could explain the rapid cooling down, a la endothermic reaction so to speak :)

> They called the event GW170817, after the date it was detected.

I am horrified by the date format in that naming convention.

I see no problem with that date. yy-mm-dd ensures that files are always ordered correctly by date.

Not true in 2100.

This is another reason why we should call this year 12017 [1], the next 12018, and so on.

[1] http://www.popularmechanics.com/science/archaeology/a24195/c...

The formula (year - 2000) * 10000 + month * 100 + day can perfectly accommodate any future dates, until we change our calendar.

But without zero-padding, it will sort wrong when using lexiographic order (as is common). 1180101 would sort before 171204 in many contexts, even though it should clearly come behind the latter.

however if we invent time travel, and go back into the year 2000 we wouldn't be able to store any event data. furthermore, to get back, if that data field was used to store event data and the coordinates to get back to the current location of earth, could send you to a divide by zero coordinate and you wouldn't be able to get back. The solution is to just ban time travel to the year 2000 until a patch comes out

I don't know, but it is possible that the GW encodes something that increases once a century or faster. There is definitely more information in two letters than two digits.

GW = gravitational wave

https://en.wikipedia.org/wiki/List_of_gravitational_wave_obs...

What you don't think the date string 120521 is unambiguous? Oh or was that 051221 or was that 210512...?

The date when it was discovered is irrelevant - no astronomer cares about that. You should think of it as a unique string associated with some data + coordinates.

But it's not unique. What if we get two gravitational hits on one day? Or what if we get one on January 1, 2019 and also one on January 1, 2119?

GRBs are named in a similar fashion with simply having an additional character at the end, for example GRB171010B is the second GRB of 2017-10-10. And the naming scheme will simply have to change in 2100 (actually probably already 2090 because the system was in use before 2000)..

Supernovae on the other hand are named with the full year followed by one or more characters to disambiguate them - for example SN1987A or SN2013EE. This is handled centrally by the IAU and takes some time, which usually means that the same object is known under many different temporary names until the official name is assigned (and only if it is an actual supernova!).

It’s bad, and for a number of alternative dates using the same formatting it would be unreadable. They were lucky in this specific case.

Not so much for others... for example, ‘GW011012’

Nice...

Isn't it just an identifier that then points to all the meta-data?

GW - gravitational wave

170817 - one of the worse ways to format a date.

It makes you wanna cry..

Most interesting to me is that the signature detected in the gravitational waves was up to 6 minutes long. With increased accuracy and quicker notification, telescopes could be aimed at such collisions before they happen. I never would have thought that was possible before.

Any spectroscopic hints pro/con for an island of stability?

Not a chance -- there's not enough to be measured.

I lack perspective here, but aren't neutron star collisions too rare to account for all the gold and other >Fe elements on Earth?

That's what I thought too. Supernovae are probably at least 100x more common and probably yield more per incident too.

There are literally tons of gold and platinum streaming through space now, just waiting to be picked up :-)

And, if you just could, it would become worthless by its very abundance.

Not a problem, if your interest lies in using them instead of storing them.

Knowledge of its availability would be sufficient to act as downward pressure on prices. Why pay $X for an ounce of gold if enough to drive the price down to one millionth of $x could come to the market at any time?

They are actually useful for other things besides representing value of course. Given the frequency of GRBs this isn't a 'rare' occurrence in the universe, and if these materials are in 'jets' then the number of rocky bodies that have been hit by a jet of this material have a high probability of existing[1]. So it might be reasonable to postulate planets with massive amounts of these metals. And certainly there are asteroids in our own solar system that Planetary Resources seeks to recover. I think once we're reasonably good as interplanetary travel we'll see a lot more of this material being made available.

[1] Where even a small probability of a collision event is overwhelmed by the sheer age of the universe and the number of events.

Besides representing value, they have value (to us). Anything that is trivially available has its value (to us) diminished compared to when it was scarce (unless new uses once again make it scarce). In any case, you're quite right that there's a lot of "precious" metals out there just waiting for us to go harvest it. The Oort cloud and the asteroid belts should prove a useful source of such materials.

Diamonds are very common, yet somehow that fact is controlled.

When people talk about diamonds being rare, they are generally talking about gemstone quality diamonds. Those, and the work needed to make them look like gemstones, are not so common.

That one is cultural. And that's true of gold as well, but not platinum.

It's kind of astounding given we're just dumb people on a dumb planet moving at uninteresting speeds or distances or times that we can predict the result of a neutron star collision and be right. Especially when our physics breaks down at those energy and gravity levels.

> Especially when our physics breaks down at those energy and gravity levels.

No, it doesn't. Neutron stars seem like very dense objects with very strong gravity to us, but their density and gravity is still well within the boundaries where our current physical theories work well. As the accuracy of these predictions illustrates.

Okay, was wondering about that. Still, it's a neutron friggin star. A star, made out of neutrons. Colliding with another. Galaxies away. And we got it right. Down to very small details. The more I think about it, the more my mind is blown.

Physics: what happens when neutron stars collide? vs CS: how do I exit vim? :)

Galaxies away, and the size of Manhattan at best.

When neutron stars collide black holes are usually formed.

At least we work within realistic timescales..

How do you really?

Reboot. The emacs solution seems to be they haven't figured out how to exit so they just stay there.

Sometimes people even write a systemd unit for it. Feature, not a bug, etc.

Yes, but it doesn't matter because emacs can do anything worth doing.

Emacs is a great OS, but a lousy editor. ;-)

Ctrl-Z, kill -9 %

That's literally what I do -- it feels safer.

> their density and gravity is still well within the boundaries where our current physical theories work well

We have no idea what goes on inside neutron stars [1].

[1] https://www.nature.com/news/neutron-stars-set-to-open-their-...

The speeds, distances, and times are only uninteresting because you are familiar with them. They are all both unimaginably large and unbearably miniscule depending on the context.

I remember hearing/reading a few times that we exist right around the median order of magnitude of things im the universe. So we might actually be interesting if only because we are unusually mediocre.

Hmm, sort of but not really. Looks like the median log length scale is ~10^-7 m, which seems pretty far from our size of ~1m.

Length of universe: unknown

Length of observable universe: ~10^27 m

Length of person: ~1 m

Planck length: ~10^-37 m

Smaller things: unknown

https://en.wikipedia.org/wiki/Orders_of_magnitude_(volume)

We're just a vaguely coherent temporary collection of membranes holding a puddle of water together round some selfish DNA, though. The clever stuff is all protein folds and chromosomes which is going on right around that magnitude. Not coincidentally, it's also right where you find the wavelengths of visible light - because structures of that kind of size are what both our eyes, and most of the things we're interested in are made out of.

I think another way to think about it is that we are able to discover a world with a scale such that we are mediocre because it's more convenient for us to place ourselves at such position. What if there exists an alternative dimension on a quark with its own universe is yet something we are able to uncover.

They got their own problems.

And that Dos Equis guy travels at all of them at once.

Uninteresting speeds that allow for us to even exist at all. Maybe not so uninteresting :) (I know what you meant though).

> we can predict the result of a neutron star collision and be right

To be fair, what we're predicting happened long ago in the past... predictions about the past are always easier :)

Touche

Hey! Don't insult my planet!

The people here... can't argue that one.

Visiting Vulcans doing the field portion of their degree in Human Studies can.

#notreallymyplanet

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