Astronomy & Space Exploration

stefan92 said:
Pretty much this. DART was pretty useless as a scientific mission, but one should essentially see it as a first test firing of our planetary defense.
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DART was an engineering exercise more than a test of physics. We know extremely precisely what would happen to the orbits if the smaller rock was hit at a given speed, angle and point of impact. What they were testing more was the ability of the spacecraft to track autonomously.

Also there's a PR side to it as well. NASA is, in many ways, always justifying its existence. Its constantly fighting the battle of "why spend billions in space when millions are starving". Whilst everything they do is valuable, this is something easily sellable to the general public.
 

This led to the first confirmed discovery of a black hole with Gaia data. The black hole is referred to as Gaia BH1 and is also the nearest black hole ever found. It is located at 480pc from the Sun, which is 3 times closer than the next-closest black hole. What a nice surprise for Gaia to find its first black hole right in our Solar neighbourhood.

The black hole was discovered by looking carefully at the companion star position. The star itself is nothing out of the ordinary, it is a Sun-like star and a plain main-sequence star. But the wobble seen in its position, as observed with great accuracy by Gaia, points to the existence of a companion. The heavier the companion, the larger the wobbling seen. This time, the wobble was caused by a heavy dormant black hole, with a weight of about 10 Solar masses.
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Buster15 said:
What does 480pc from the sun mean. Is it 480 parsec?
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Yep! 1 parsec = approximately 3.26 light-years, so Gaia BH1 is at a distance of about 1550 light-years. V Puppis (also a binary system, supposedly: Evidence of a Massive Black Hole Companion in the Massive Eclipsing Binary V Puppis) is even closer at a distance of about 1150 light-years, but the presence of a black hole has not been confirmed.
Buster15 said:
Also, what are the units on the graph?
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X axis (Porb) = orbital period in days (approximately 185)
Y axis (M☉) = mass in Solar equivalents (approximately 9.6)
 
Invictus said:
Yep! 1 parsec = approximately 3.26 light-years, so Gaia BH1 is at a distance of about 1550 light-years. V Puppis (also a binary system, supposedly: Evidence of a Massive Black Hole Companion in the Massive Eclipsing Binary V Puppis) is even closer at a distance of about 1150 light-years, but the presence of a black hole has not been confirmed.

X axis (Porb) = orbital period in days (approximately 185)
Y axis (M☉) = mass in Solar equivalents (approximately 9.6)
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Yet again, I am very appreciative of your help and advice.
Clever chap.
 
Just rewatched this for the first time in a while. An unvarnished look inside mission control during the minutes before & after confirmation the space shuttle Columbia's broke up during reentry...

 
RedDevilQuebecois said:
Seriously, NASA just sucks. If they can't get it done for an unmanned flight, what will it be like when they will have astronauts on board?

Historic moon mission troubleshoots fuel leak issue hours before launch

You ain't making an omelette without breaking eggs.
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I think they will get to the moon this decade, but it won't be via SLS. They will want to get a launch in just to make some use of the 20 billion spent though.

Orion has already been launched into orbit outside of SLS and the moon mission is partially going to use SpaceX anyway so I think they'll choose a different launch vehicle to get there with the decision announced in 2023.

It'll also cost them about a quarter of how much an SLS launch costs and will be capable of launching over once per year.
 
It looks like it could launch in 5 minutes. This is going to be a good watch.
 
RedDevilQuebecois said:
Seriously, NASA just sucks. If they can't get it done for an unmanned flight, what will it be like when they will have astronauts on board?

Historic moon mission troubleshoots fuel leak issue hours before launch

You ain't making an omelette without breaking eggs.
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You have to get it right. This isn't an unmanned cargo ship or glorified sounding rocket (looking at you Bezos), and they dont have a decade to blow rockets up like they did in the 60s. There will be people on the next one.

It takes 100x more energy to get to LEO than it does to space, so you can imagine how much harder it is to go to the moon, and then come back again. The last time there was a mission this complex was 1972, don't let Elon Musk con you. There's a reason Starship still hasn't flown.
 
Counterfactual said:
It boggles my mind how we are conscious of our existence and capable of querying the Universe, only to find out how unfathomably complex it is. If we don't understand the largest scale (dark matter), the smallest scale (quantum) or the individual scale (our brain/mind), what do we actually understand?

"There is a theory which states that if ever anyone discovers exactly what the Universe is for and why it is here, it will instantly disappear and be replaced by something even more bizarre and inexplicable. There is another theory which states that this has already happened." (Douglas Adams)

I wonder if it happens in real-time, as each layer is understood another appears...
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It’s like my cat figuring out we are going off somewhere without him. Once the car goes out of the driveway, we are out of sight. He senses the mood, the change of tone. He even knows a few words in our conversation. ‘Food’; ‘Out’; ‘cat’; the name we have given him. He’s surprisingly smart.

Like the cat, we know a lot; every inch of our backyard. We dimly see the past and future. The context of the drivers behind cosmology is closed off to us, though; the real story is out of reach of our cerebral capacity, and sealed forever beyond the event horizon.
 
Tincanalley said:
It’s like my cat figuring out we are going off somewhere without him. Once the car goes out of the driveway, we are out of sight. He senses the mood, the change of tone. He even knows a few words in our conversation. ‘Food’; ‘Out’; ‘cat’; the name we have given him. He’s surprisingly smart.

Like the cat, we know a lot; every inch of our backyard. We dimly see the past and future. The context of the drivers behind cosmology is closed off to us, though; the real story is out of reach of our cerebral capacity, and sealed forever beyond the event horizon.
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What if the event horizon were not the point of no return, but the point of entry? What if there were "white holes" which brought forth matter? What if that was how this (and other) universes started?

"To black hole physicists, the Big Bang's explosion of matter and energy looks like potential white hole behavior. "The geometry is very similar in the two cases," Haggard said. "Even to the point of being mathematically identical at times."
(space.com)
 
11101 said:
You have to get it right. This isn't an unmanned cargo ship or glorified sounding rocket (looking at you Bezos), and they dont have a decade to blow rockets up like they did in the 60s. There will be people on the next one.

It takes 100x more energy to get to LEO than it does to space, so you can imagine how much harder it is to go to the moon, and then come back again. The last time there was a mission this complex was 1972, don't let Elon Musk con you. There's a reason Starship still hasn't flown.
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It's insanely difficult, yes but there's no denying that NASA unfortunately took a lot of wrong decisions on Artemis and are paying for that now. I haven't read an actual rocket expert say that it's been anything but a waste of money getting to where we are now. A lot of the people saying it should be scrapped are ex NASA engineers.

Comparing it with starship is frankly ludicrous considering the difference in time taken and money spent so far. It's a fraction of the budget and has had static fire tests and will probably launch later this year or early next. It'll probably have issues, but that's where Boeing are getting it wrong in development making something that's too expensive to fail even once.

The good news is that NASA have seen the failings and have decided not to contract with partners this way any more and will go fixed fee for future projects and alliances. We definitely won't see another SLS type project after this one.
 
Balljy said:
It's insanely difficult, yes but there's no denying that NASA unfortunately took a lot of wrong decisions on Artemis and are paying for that now. I haven't read an actual rocket expert say that it's been anything but a waste of money getting to where we are now. A lot of the people saying it should be scrapped are ex NASA engineers.

Comparing it with starship is frankly ludicrous considering the difference in time taken and money spent so far. It's a fraction of the budget and has had static fire tests and will probably launch later this year or early next. It'll probably have issues, but that's where Boeing are getting it wrong in development making something that's too expensive to fail even once.

The good news is that NASA have seen the failings and have decided not to contract with partners this way any more and will go fixed fee for future projects and alliances. We definitely won't see another SLS type project after this one.
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Don't disagree with any of that but I was replying to a post suggesting they shouldn't be delaying again to troubleshoot a leak, like they should just go for it. Nothing to do with cost and delays.

Starship was actually first started in 2005 as the BFR, only a year later than the original Constellation program. These massive missions take a long time.
 
11101 said:
Don't disagree with any of that but I was replying to a post suggesting they shouldn't be delaying again to troubleshoot a leak, like they should just go for it. Nothing to do with cost and delays.

Starship was actually first started in 2005 as the BFR, only a year later than the original Constellation program. These massive missions take a long time.
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That's fair, they wouldn't and shouldn't take risks on a mission of this size.

I'd argue that 2005 was when it was mentioned as a concept, but was going to use variations of the merlin engine. It was in 2010 that they announced the idea of the raptor engine and that fired in 2016. The upper stage was developed from around 2018 and the final concept was announced then.

The engine has definitely taken them a long time and it feels like that's what they were waiting on before developing further. That's also the biggest risk for them for sure with the move to methane.
 
MrMarcello said:
At the pub last night, the topic of space and travel came up. One mentioned the double-slit theory. Can someone go into that?
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It is not a theory. It has been demonstrated by experiments.
It is the way the light from the Sun is both a wave, light waves and individual quanta.
Wikipedia explains it far more succinctly than I ever could so I would recommend you googling it.
It also demonstrates that individual particles, quantum particles can be in 2 places at the same time.
 
Denis79 said:
What always gets me with these pictures is when a small speck of light is a galaxy, a frickin galaxy with billions of stars!
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I always get that same feeling as well. I mean, the sheer scale of everything is just mind blowing.
 
Raoul said:
An ideal destination for Musk to fly to check if its worthy of humanity moving there.

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Based on pure probability, there could be billions of them out there in the various billions of galaxies.
 
dinostar77 said:
Only recently came across the mystery of The Great Attractor.

https://www.universetoday.com/15843...axy-cluster-found-behind-the-milky-ways-disk/

Also only recently came across the Diapole Repeller.

The universe is indeed a fascinating place.
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I don't think that site gives a great description of The Great Attractor. Most importantly, we're not actually really moving towards it, nor are we heading towards the Virgo Cluster. They do sort of get at it in the article when they explain Hubble flow (the expansion of space causing almost everything to move away from almost everything else), and some movement coming "on top of" that, but they seem to put Andromeda, the Virgo Cluster and The Great Attractor on the same level. At this point we're only gravitationally bound to the Local Cluster (us, Andromeda and our small-ish posse of smaller galaxies). We'll only ever be moving further away from everything else, unfortunately.

All that said, these cosmic mysteries are still really interesting!
 
nimic said:
I don't think that site gives a great description of The Great Attractor. Most importantly, we're not actually really moving towards it, nor are we heading towards the Virgo Cluster. They do sort of get at it in the article when they explain Hubble flow (the expansion of space causing almost everything to move away from almost everything else), and some movement coming "on top of" that, but they seem to put Andromeda, the Virgo Cluster and The Great Attractor on the same level. At this point we're only gravitationally bound to the Local Cluster (us, Andromeda and our small-ish posse of smaller galaxies). We'll only ever be moving further away from everything else, unfortunately.

All that said, these cosmic mysteries are still really interesting!
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As usual well explained.
 
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