Astronomy & Space Exploration

nickm

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Given that the guy you linked to went to university the first time in 1957, I'm going to guess he's not a 17 year old intern.

Also I actually have a mutal contact with this older guy!
True. Best CV I've ever read though.

Watch out for this one though: https://en.wikipedia.org/wiki/Sabrina_Gonzalez_Pasterski
  • Born 1993.
  • Built her own airplane in 2006, aged 13
  • Piloted her own airplane in 2009, aged 16.
  • At age 21, discovered "spin memory effect" which may be used to detect or verify the net effects of gravitational waves
  • Got her PhD in theoretical physics at 22.
 

nickm

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I like the way he doesnt bother to mention the 6 Space Shuttle missions until over half way down his page. Just like 'oh and then there was this other thing i once did'.
I also liked the way he warms you up with being a professor of industrial design and astronaut, then just as you are reeling from that, he hits you with also being a trauma surgeon, emergency room doctor, and researcher in brain surgery.

His other professorship in biological engineering is by this point, showing off,
 

11101

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I also liked the way he warms you up with being a professor of industrial design and astronaut, then just as you are reeling from that, he hits you with also being a trauma surgeon, emergency room doctor, and researcher in brain surgery.

His other professorship in biological engineering is by this point, showing off,
I genuinely don't understand how you can be a fecking brain surgeon and an astronaut in one lifetime, two things that take the absolute cream of the crop an entire career to master. Let alone all the other shit he's also done.
 

edcunited1878

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The Daniel K. Inouye Solar Telescope has produced the highest resolution observations of the Sun’s surface ever taken. In this movie, taken at a wavelength of 705nm over a period of 10 minutes, we can see features as small as 30km (18 miles) in size for the first time ever. The movie shows the turbulent, “boiling” gas that covers the entire sun. The cell-like structures – each about the size of Texas – are the signature of violent motions that transport heat from the inside of the sun to its surface. Hot solar material (plasma) rises in the bright centers of “cells,” cools off and then sinks below the surface in dark lanes in a process known as convection. In these dark lanes we can also see the tiny, bright markers of magnetic fields. Never before seen to this clarity, these bright specks are thought to channel energy up into the outer layers of the solar atmosphere called the corona. These bright spots may be at the core of why the solar corona is more than a million degrees!

This movie covers an area 19,000 x 10,700 km (11,800 x 6,700 miles or 27 x 15 arcseconds).
 

Buster15

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The Daniel K. Inouye Solar Telescope has produced the highest resolution observations of the Sun’s surface ever taken. In this movie, taken at a wavelength of 705nm over a period of 10 minutes, we can see features as small as 30km (18 miles) in size for the first time ever. The movie shows the turbulent, “boiling” gas that covers the entire sun. The cell-like structures – each about the size of Texas – are the signature of violent motions that transport heat from the inside of the sun to its surface. Hot solar material (plasma) rises in the bright centers of “cells,” cools off and then sinks below the surface in dark lanes in a process known as convection. In these dark lanes we can also see the tiny, bright markers of magnetic fields. Never before seen to this clarity, these bright specks are thought to channel energy up into the outer layers of the solar atmosphere called the corona. These bright spots may be at the core of why the solar corona is more than a million degrees!

This movie covers an area 19,000 x 10,700 km (11,800 x 6,700 miles or 27 x 15 arcseconds).
Fantastic really.
We all take our Sun pretty much for granted and yet we are all totally reliant on it for literally everything.
And it works simply by the process of Nuclear Fusion, the fusion initially of two hydrogen atoms into helium.

The detailed process is actually quite complex to both achieve and even more to comprehend and requires three of the fundamental forces to interact almost instantly.
The strong force to overcome the electromagnetic force due to the hydrogen protons being positively charged.
Then the weak force to convert one of the protons into a neutron.
And then the release of mass as the two hydrogen atoms become a helium atom (helium 4 to be precise).

And that release of a tiny amount of mass gets converted into energy.

But it does not finish there because it can take millions of years for that energy in the form of photons to reach the surface of the sun and then travel at the speed of light (photons are massless) to reach the earth.

And we take all that for granted.
 

nickm

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Obsessed with Betelgeuse at the moment. Sorry if this is a repost.


Blows my mind we can image a star that’s 700 light years away and see a disc. Helps that Betelgeuse is so enormous. Could the dimming means it’s about (relatively speaking) to go supernova?
 

Invictus

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Obsessed with Betelgeuse at the moment. Sorry if this is a repost.


Blows my mind we can image a star that’s 700 light years away and see a disc. Helps that Betelgeuse is so enormous. Could the dimming means it’s about (relatively speaking) to go supernova?
Ok, so there's something called “variability” with pulsating stars (in this instance we will refer to only photometric variability — i.e. variability in terms of perceived brightness or magnitude because of periodic shifts in thermonuclear energy being expended and convective cell transfer activity and radial-velocity changes). Our own sun evidences variability, too (over a roughly 11 year cycle when the poles flip completely from North to South and vice versa, which causes a lot of periodic turbulence)...



Any apparent dimming of Betelgeuse leads to a lot of excitement because folks expect it to go supernova at last, but that typically coincides with its variability — which unpredictable to a degree, but approximately 60 months for primary variations and 18-300 months for secondary long-short cycle variations, and when primary and secondary variations coincide you can get extreme dimming (which might explain the events of recent months). The disc shape could be due to ejection of gas or dust propagated by stellar winds (which can distort the image), at least for now as the observations are not conclusive.

EDIT: For what it's worth, poor Eta Carinae is theoretically more likely to go supernova in the astronomic near future than Betelgeuse, but doesn't get as much fanfare... :(
 
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Balljy

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The disc shape could be due to ejection of gas or dust propagated by stellar winds (which can distort the image), at least for now as the observations are not conclusive.
I was reading that the two theories on to the odd shape it appears to have formed in the last year are either due to dust like you have said or because of the sheer size of the star where the outer reaches would be around Jupiter in out solar system.

The theory is that due to the scale of Betelgeuse the distance between the core and the area where it generates a magnetic field allows greater cooling and therefore sun spots covering massive areas of its surface rather than just the relatively small areas on ours.

 

nickm

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Ok, so there's something called “variability” with pulsating stars (in this instance we will refer to only photometric variability — i.e. variability in terms of perceived brightness or magnitude because of periodic shifts in thermonuclear energy being expended and convective cell transfer activity and radial-velocity changes). Our own sun evidences variability, too (over a roughly 11 year cycle when the poles flip completely from North to South and vice versa, which causes a lot of periodic turbulence)...



Any apparent dimming of Betelgeuse leads to a lot of excitement because folks expect it to go supernova at last, but that typically coincides with its variability — which unpredictable to a degree, but approximately 60 months for primary variations and 18-300 months for secondary long-short cycle variations, and when primary and secondary variations coincide you can get extreme dimming (which might explain the events of recent months). The disc shape could be due to ejection of gas or dust propagated by stellar winds (which can distort the image), at least for now as the observations are not conclusive.

EDIT: For what it's worth, poor Eta Carinae is theoretically more likely to go supernova in the astronomic near future than Betelgeuse, but doesn't get as much fanfare... :(
I remember Betelgeuse was one of the first star names I ever learned as a kid, and of course it's smack in the middle of one of the easier to spot constellations, so I guess there's a bit of romance there that say Eta Carinae lacks. But you are probably right it's part of the natural cycle (although I'm still crossing my fingers for the Dyson sphere).
 

altodevil

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When was the last time a supernova was observed by mankind? (if at all)
Happens occasionally I think, human eye detectable I assume you mean. Definitely a fair few in written record. See the crab nebula etc
 

Invictus

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When was the last time a supernova was observed by mankind? (if at all)
The last live supernova to be detected by the unaided eye was SN1604 in 1604 in the Ophiuchus constellation. We have since observed many other supernovae with telescopes (like the famous ASASSN-15lh: https://arxiv.org/abs/1507.03010), but none with an unaided eye, and none in the Milky Way — which can be too close to focus on, and too shrouded in interstellar dust...that makes it very, very hard to stumble across one as there are only 2-3 supernovae in the Milky Way per century (the general observable universe gives us a much better chance of detecting a live one with vast expanses of intergalactic space and billions of galaxies).

By the way, SN1604 was quite significant for cosmology, and led to the overthrowing of the Aristotelian geocentric system:
The conventional view of the cosmos placed the Earth at the center of our solar system, and in fact the whole universe. This Earth-centric worldview came originally from Aristotle and Ptolemy, two ancient philosophers. Aristotle’s On the Heavens said that the Earth was the realm of imperfect things and was changeable, while things far away from the Earth were perfect and didn’t change. From these principles, he developed a complicated model that could (sort of) accurately predict the movement of planets in the Solar System and other observable phenomena.

The 1604 supernova was the last one recorded in the Milky Way to date, but in the preceding century, astronomers had observed another of these rare events as well as a smaller nova. Aristotle’s perspective didn’t account for these events.

At this point, Galileo was a lecturer in mathematics and Kepler was the Imperial Mathematician in Germany, a position that Brahe previously held. Their positions required that both of them make attempts to figure out what the supernova was and answer the question of what it represented.

These observations, which came at a turning point in the history of understanding of the cosmos, provided the groundwork for further theorizing that eventually led to the understanding that the Earth was not the center of the universe. However, the astronomers who believed they were seeing the birth of a new star were wrong: they were seeing brilliant celestial deaths happening close to home, the kind that modern astronomers can only wish to observe.
https://www.smithsonianmag.com/smar...va-presented-challenge-astronomers-180965138/
 

RobinLFC

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During morning coffee, colleague of mine was enthusiastically telling me about some shit going down at the ISS today, supposed to be happening right now. We're watching it together and so far it's been quite boring.

It's supposed to be the capture of some robot?
 

Invictus

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This is a surprisingly good watch/listen:



On a tangential note, you have to wonder how many views a comparable but non-mainstreamed 2-3 hours long academic talk would have, surely much lower than 1.5 million in just 2 days? :lol:
 

Amarsdd

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This is a surprisingly good watch/listen:



On a tangential note, you have to wonder how many views a comparable but non-mainstreamed 2-3 hours long academic talk would have, surely much lower than 1.5 million in just 2 days? :lol:
very true. These are some of my favorite Joe Rogan's podcasts including Sean Carroll, Brian Cox, Neil DeGrasse Tyson etc where Joe is genuinely curious and trying to understand the subject.
 

17 Van der Gouw

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Scientists detect "biggest explosion since big bang"

https://www.bbc.co.uk/news/science-environment-51669384

Scientists have detected evidence for a colossal explosion in space - five times bigger than anything observed before.

The huge release of energy is thought to have emanated from a supermassive black hole some 390 million light years from Earth.

The eruption is said to have left a giant dent in the Ophiuchus galaxy cluster.


Fascinating find.
 

ArmandTamzarian

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Scientists detect "biggest explosion since big bang"

https://www.bbc.co.uk/news/science-environment-51669384





Fascinating find.
:eek:

"I've tried to put this explosion into human terms and it's really, really difficult," co-author Melanie Johnston-Hollitt told BBC News.

"The best I can do is tell you that if this explosion continued to occur over the 240 million years of the outburst - which it probably didn't, but anyway - it'd be like setting off 20 billion, billion megaton TNT explosions every thousandth of a second for the entire 240 million years. So that's comprehensibly big. Huge."
 

17 Van der Gouw

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I know right?!

I love how, despite being unfathomably large, literally astronomically huge, in the grand scheme of the cosmos that explosion is but a small blip, a tiny dot in the observable universe.

When you consider the size of our planet in comparison - and our physical forms as humans, we are like nothing, not even specs of dust in the universe.
 

17 Van der Gouw

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Can somebody who knows better explain something to me?

Astronauts have said that space smells of "diesel fumes and barbecue" - and I've read that this smell is caused by dying stars.

But what I can't grasp, is how would it be possible, even with the age of the universe, for that smell to have permeated close enough for human astronauts to be able to smell it?

Stars are light years apart, hundreds of trillions of miles. I don't understand how said smell could have reached us yet.
 

nimic

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Astronauts have no idea what space smells like, they've never been directly exposed to it. They're probably talking about the smell on the space station.

Apart from that, if there was a smell, there's no reason to think it wouldn't have reached us. The very fact that we're here is evidence that stuff from exploding stars has reached us, since many of the elements we're made of are the result of stars blowing up and seeding the surrounding (massive) area with those elements.
 

NWRed

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Can somebody who knows better explain something to me?

Astronauts have said that space smells of "diesel fumes and barbecue" - and I've read that this smell is caused by dying stars.

But what I can't grasp, is how would it be possible, even with the age of the universe, for that smell to have permeated close enough for human astronauts to be able to smell it?

Stars are light years apart, hundreds of trillions of miles. I don't understand how said smell could have reached us yet.
I've never heard of an astronaut saying tht and I don't understand how an astronaut in a necessarily hermetically sealed space vehicle could be 'smelling' anything in open space, but I do know that every particle of you that isn't Hydrogen or Helium was made inside a dying star that went supernova billions of years ago.
 

Ubik

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Can somebody who knows better explain something to me?

Astronauts have said that space smells of "diesel fumes and barbecue" - and I've read that this smell is caused by dying stars.

But what I can't grasp, is how would it be possible, even with the age of the universe, for that smell to have permeated close enough for human astronauts to be able to smell it?

Stars are light years apart, hundreds of trillions of miles. I don't understand how said smell could have reached us yet.
Our whole solar system is the remnant of dead stars, so we can never be too far away from it.

Supposedly the astronauts know about it because the particles adhered to space suits and then reacted to the atmosphere aboard the station.
 

Buster15

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Can somebody who knows better explain something to me?

Astronauts have said that space smells of "diesel fumes and barbecue" - and I've read that this smell is caused by dying stars.

But what I can't grasp, is how would it be possible, even with the age of the universe, for that smell to have permeated close enough for human astronauts to be able to smell it?

Stars are light years apart, hundreds of trillions of miles. I don't understand how said smell could have reached us yet.
But astronauts have never actually been exposed to 'smelling' space. They only breathe air generated here on earth.

If they smell something mechanical, it may be from their space capsule or ISS which is contaminating their air.

While we know that space is made up of nothing, the concentration of anything must be so miniscule as to be negligible.
The human can smell particles down to a few ppm.
But we must remember that space is extremely cold, being just about absolute zero. And the sense of smell deteriorates with temperature.
 

17 Van der Gouw

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Thanks all, I feel a bit silly for not considering the historical proximity of, well, everything in the universe.

...and as many of you have pointed out, nobody has ever smelled the vacuum directly. although @Ubik makes an excellent point about bringing particles 'inside' after EVAs - after all, a number of astronauts have said the same thing about space 'smelling' like burnt steak. I also pondered the same thing as @Buster15 - that it's possible that they're actually spelling machinery or equipment.
 

nimic

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But we must remember that space is extremely cold, being just about absolute zero.
2.73 Kelvin, to be precise. Quite cold, though we've made it colder on Earth.

Actually, it's possible that the lowest and highest temperatures ever to exist in the Universe have existed on Earth, at least in the last few billion years. Probably not, but it could be true.
 

17 Van der Gouw

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2.73 Kelvin, to be precise. Quite cold, though we've made it colder on Earth.

Actually, it's possible that the lowest and highest temperatures ever to exist in the Universe have existed on Earth, at least in the last few billion years. Probably not, but it could be true.
Do you mean those record highs and lows may have existed on Earth, as well as in other places at other times, or just on Earth?

You know much more about the subject than I do, but surely the sheer magnitude of stars and planets in the universe would make it highly improbable?

Don't flame me too hard, I'm an amateur.
 

nimic

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Do you mean those record highs and lows may have existed on Earth, as well as in other places at other times, or just on Earth?

You know much more about the subject than I do, but surely the sheer magnitude of stars and planets in the universe would make it highly improbable?

Don't flame me too hard, I'm an amateur.
It doesn't take into account the possibility of equally or more advanced aliens, but that's a complete unknown to us right now. But we've created temperatures both lower and higher in labs than are naturally occurring in the Universe (as far as we know). The caveat to the "higher" part of that is that the very, very early Universe was very, very strange, and creating such high temperatures has among other things been to explore the conditions of that early Universe.
 

17 Van der Gouw

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It doesn't take into account the possibility of equally or more advanced aliens, but that's a complete unknown to us right now. But we've created temperatures both lower and higher in labs than are naturally occurring in the Universe (as far as we know). The caveat to the "higher" part of that is that the very, very early Universe was very, very strange, and creating such high temperatures has among other things been to explore the conditions of that early Universe.
Thanks.

Ah, of course, temperatures reached under artificial conditions.

I suppose the discussion about the likelihood of other intelligent life would derail your point somewhat, but this is a probably a good place to share a thought that crossed my a couple of days ago.

I was watching a trending YouTube video discussing explanations for the Fermi Paradox, and they were doing all kinds of mental gymnastics with ideas ranging from aliens already being among us, to simulation theory all the way to proposing that there's no other life in the milky way. But they neglected to consider, what I just think is the most obvious and logical explanation, which is quite simply scale. There are ~300-400bn stars in our galaxy, each with (literally) astronomical distances between them. Given the rarity of the prerequisite conditions for life on any given planet (or at least life as we know it) - it's likely the potential lifeforms are relatively scarce, and possibly spread out - thus the chances of them finding our little planet, nestled three worlds away from an unremarkable star are rather low.

Especially if we consider that they've not yet found a way around the universal speed limit!

Sorry to de-rail.
 

Buster15

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2.73 Kelvin, to be precise. Quite cold, though we've made it colder on Earth.

Actually, it's possible that the lowest and highest temperatures ever to exist in the Universe have existed on Earth, at least in the last few billion years. Probably not, but it could be true.
I was referring to the point that human sense of smell deminishes the colder it gets.
But appreciate your input.
 

Buster15

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I don't think we do know that.
I meant to say that we know that space is not made of nothing.

What we used to think of as an empty vacuum is actually full of 'stuff'.

That being dark energy, dark matter and quantum fields.
Plus I am sure things that we currently don't know of.
Fascinating.