Astronomy & Space Exploration

In other news, I see Osiris Rex is go for stow. Its sample scattering as it makes a dash for the bathroom door.
 
Brilliant stuff. If anyone hasn't bookmarked his channel, highly recommended. Could watch these all day.

 
The Arecibo Observatory Platform Has Collapsed
https://www.universetoday.com/149029/the-arecibo-observatory-platform-has-collapsed/

"Early this morning, the 900-ton instrument platform suspended above the Arecibo Observatory collapsed and crashed down on the iconic telescope’s giant dish. The collapse occurred at about 7:55 a.m. local time, officially ending any possible hopes of refurbishing the famous observatory in Puerto Rico."

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Oh no! Where will action movies shoot their showdowns now?
 
Always wanted to visit Arecibo ever since falling in love with Contact; was hoping it'd be turned into some kind of tourist attraction since it was decommissioned recently but I guess there's no chance of that happening now...
 
Starship has a fun debut flight

 
Looks like it just needed more juice at the end. Good flight until that point.
 
11101 said:
Looks like it just needed more juice at the end. Good flight until that point.
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One of the engines packed up and the remaining one lost fuel pressure (that's why it started burning green). I was thinking it was gonna blow up on engine restart, so a loss is a win here!
 
Watched last night live. I was so annoyed by the original delay (but only if it was stopped cus of a freaking drone!)

but so worth it. Elon musk has advanced space travel 50 years. If I'm going to lose join the 100 mile high club before i did it's SpaceX that will get us there.

freaking amazing
 
nimic said:
SpaceX has advanced space travel 50 years, you mean.
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Bit of both really, his vision at least has created demand. Any major endeavour needs that especially one who gives the freedom to innovate and fail. Not sure about 50 years though.

I happened to catch it live last night and as always blown away. The scale of that made it look like a thunderbirds puppet. Especially the disappearing magic trick at the end :lol:

I was left wondering why they don't have contingencies for a raptor engine failure. I assume in the future they'd be able to identify low pressure and start the burn sooner to compensate and not slam into the ground.
 
nimic said:
SpaceX has advanced space travel 50 years, you mean.
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Oh man, let's keep that discussion to the epic bacon thread :lol:

Still, a lot to prove out for the system to work. Re-entering with a winged body creates problems, particularly when said wings are needed to land without a boom. Can't see there being a crew version until it's flown a lot (100+ times) as the cargo variant. Then again, if it's as reusable as Musk says it should be, that might not take that long in the grand scheme.
Smores said:
Bit of both really, his vision at least has created demand. Any major endeavour needs that especially one who gives the freedom to innovate and fail. Not sure about 50 years though.

I happened to catch it live last night and as always blown away. The scale of that made it look like a thunderbirds puppet. Especially the disappearing magic trick at the end :lol:

I was left wondering why they don't have contingencies for a raptor engine failure. I assume in the future they'd be able to identify low pressure and start the burn sooner to compensate and not slam into the ground.
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Yeah, I do wonder if they'll build a little extra margin on that front, not great for the generally used term for your landing method to be "suicide burn." Although in this case, they basically had no engines by the end so it was only ending one way.
 
nimic said:
SpaceX has advanced space travel 50 years, you mean.
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Elon Musk has.

Without him, the space industry looks the same as it has for the last 30 years. The "industry" has two purposes; launching weather and TV satellites into space, and taking as much money from NASA as possible to fulfil whatever task they decide to do. There is no innovation there. There is no Thomas Eddison or Henry Ford.

The Obama Administration should be lauded for trying commercial contracts of the type that allows SpaceX to exist, and taking a big chance on SpaceX, and maybe in a world where there is no SpaceX, Sierra Nevada or Blue Origin or Boeing or someone else benefit and develop hardware. But that still isnt innovation.

Boeing expected to get additional payments on top of what was originally promised to do commercial crew. They expected to be like the Lockheed Martins X-35 where they could request payment after payment to contribute to development. They had absolutely no intention of building Starliner at cost, and you can say the same for everyone else. SpaceX not only built Crew Dragon first, not only did they build it cheaper, they are putting their own money on the table to build Starship.

There is precisely 1 "hundred-man" orbital spacecraft in development right now. There is precisely 1 "fully reusable" orbital spacecraft in development. It's being funded by Musk. It's being designed by Musk. It's being pushed forwards by Musk.
 
https://mars.nasa.gov/mars2020/timeline/landing/entry-descent-landing/

Entry, Descent, and Landing – often referred to as "EDL" – is the shortest and most intense phase of the Mars 2020 mission. It begins when the spacecraft reaches the top of the Martian atmosphere, travelling nearly 12,500 miles per hour (20,000 kilometers per hour). It ends about seven minutes later, with Perseverance stationary on the Martian surface. To safely go from those speeds down to zero, in that short amount of time, while hitting a narrow target on the surface, requires “slamming on the brakes” in a very careful, creative and challenging way.
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The technology that has been developed since my youth days in the 80s has me excited and intrigued on what's happening the next 30 days. I hope I'm around to see man on Mars/elsewhere.
 
Anyone read 'The Elegant Universe' from Brian Greene? Just finished it and definitely loved it. Intuitive explanations of relativity and quantum mechanics (was familiar with both) before diving into string theory. For most part it was quite understandable (as understandable as these concepts can be without math).
 
Revan said:
Anyone read 'The Elegant Universe' from Brian Greene? Just finished it and definitely loved it. Intuitive explanations of relativity and quantum mechanics (was familiar with both) before diving into string theory. For most part it was quite understandable (as understandable as these concepts can be without math).
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Am I right that it was published in 1999?
If so, is it, in your opinion still up to date with current thinking.
 
Buster15 said:
Am I right that it was published in 1999?
If so, is it, in your opinion still up to date with current thinking.
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I think it is alright. There are some things that are slightly outdated, for example back then it was not clear that the universe was expanding faster. Additionally, some of the hopes for LHC didn’t bring anything (for example supersymmetry hasn’t been found yet), and the holography was at inception (ADS-CFT correspondence was done just a couple of years earlier).

Nevertheless, it was a very good book, it explained well the known physics (relativity, QM) and it gives the best explanation for laymen of string theory I have ever seen. Just keep in mind, that a lot of things have been developed since then, and there is a lot of less hype for string theory (mostly cause it still hasn’t been able to make any predictions).
 
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Revan said:
I think it is alright. There are some things that are slightly outdated, for example back then it was not clear that the universe was expanding (the cosmological constant not being zero). Additionally, some of the hopes for LHC didn’t bring anything (for example supersymmetry hasn’t been found yet), and the holography was at inception (ADS-CFT correspondence was done just a couple of years earlier).

Nevertheless, it was a very good book, it explained well the known physics (relativity, QM) and it gives the best explanation for laymen of string theory I have ever seen. Just keep in mind, that a lot of things have been developed since then, and there is a lot of less hype for string theory (mostly cause it still hasn’t been able to make any predictions).
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Good. Because of all the mindbendingly difficult things for me to even try to comprehend, it was String Theory....
As someone who obviously has a good grasp of things, what is your view on Cosmic/Eternal Inflation. This theory has a great deal of followers and is almost mainstream thinking.
The part I still struggle with is concept of the Scalar Field. In particular how something so incredibly minute could end up with our universe.
 
Buster15 said:
Good. Because of all the mindbendingly difficult things for me to even try to comprehend, it was String Theory....
As someone who obviously has a good grasp of things, what is your view on Cosmic/Eternal Inflation. This theory has a great deal of followers and is almost mainstream thinking.
The part I still struggle with is concept of the Scalar Field. In particular how something so incredibly minute could end up with our universe.
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Yeah, String Theory is hard to understand, especially when done without the math. Even in the book, there are parts that you just have to pretend that you understand, and it was really hard to get more than the basic intuition when Greene talks for stuff like the duality of Calabi-Yau manifolds (I guess I was able to understand the idea of Calabi-Yau spaces and I can well understand the concept of duality having used it many times, but putting everything together without the equations and the preliminary knowledge is just impossible).

About the inflation, I hardly know much. From what I know of it, the inflation is generally accepted as a fact, while the eternal inflation is one of the ways to make the theory complete. I remember hearing Lenny Susskind that it is his favorite theory of inflation, which is not hard to imagine, considering that it perfectly fits with his idea of the cosmic landscape of the multiverse.
 
MrMarcello said:
https://www.newyorker.com/magazine/...en-visited-by-aliens?utm_source=pocket-newtab
Have We Already Been Visited by Aliens?
An eminent astrophysicist argues that signs of intelligent extraterrestrial life have appeared in our skies. What’s the evidence for his extraordinary claim?
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Putting this particular case aside. Broadly I think the mostly likely scenario for a civilisation to explore the universe/galaxy may simply be probes. I doubt we'd ever notice, but it certainly wouldn't shock me if some unimaginably advanced life-form decided to catalogue the galaxy per se via probes and we'd never find out.
 
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