Astronomy & Space Exploration

Invictus said:
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Mindblowing. How did it not degrade into minuscule particles over such a stupendous amount of time?
Sorry if the question is very silly. As you may infer, I barely managed to pass my chemistry class in high school.
 
RoyH1 said:
Mindblowing. How did it not degrade into minuscule particles over such a stupendous amount of time?
Sorry if the question is very silly. As you may infer, I barely managed to pass my chemistry class in high school.
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Won't have been on Earth for long enough. In space, things are very far apart.
 
RoyH1 said:
Mindblowing. How did it not degrade into minuscule particles over such a stupendous amount of time?
Sorry if the question is very silly. As you may infer, I barely managed to pass my chemistry class in high school.
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Luck. Most material like this did get destroyed or incorporated into larger bodies over time. This one managed to survive long enough to fall through our atmosphere at some point in the last few years.
 
RoyH1 said:
Mindblowing. How did it not degrade into minuscule particles over such a stupendous amount of time?
Sorry if the question is very silly. As you may infer, I barely managed to pass my chemistry class in high school.
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Andesite is a very strong intermediate volcanic rock that doesn't easily erode. Also, it may be 4.565 billion years old but that doesn't mean it has been on Earth for that amount of time; in fact it probably landed here relatively recently.
 
RoyH1 said:
Mindblowing. How did it not degrade into minuscule particles over such a stupendous amount of time?
Sorry if the question is very silly. As you may infer, I barely managed to pass my chemistry class in high school.
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Conventional astrochemical wisdom would dictate that it hasn't actually been on Earth for a significant amount of time, hence the relative lack of erosion — maybe it is cosmic debris that originated in another star system and was whimsically floating around in space before succumbing to the Earth's gravitational field, maybe it is a relic of our Sun's primordial accretion disc that landed on Earth in the recent past, or some other predictive theory.

There are much older meteorites on Earth as well, like fragments of the one that fell in Murchison, Australia — which are estimated * to be older than the Solar System itself!




* The estimates can vary a bit — from a minimum of ~4 billion years to a maximum of ~7 billion years.
 
Invictus said:
Conventional astrochemical wisdom would dictate that it hasn't actually been on Earth for a significant amount of time, hence the relative lack of erosion — maybe it is cosmic debris that originated in another star system and was whimsically floating around in space before succumbing to the Earth's gravitational field, maybe it is a relic of our Sun's primordial accretion disc that landed on Earth in the recent past, or some other predictive theory.

There are much older meteorites on Earth as well, like fragments of the one that fell in Murchison, Australia — which are estimated * to be older than the Solar System itself!




* The estimates can vary a bit — from a minimum of ~4 billion years to a maximum of ~7 billion years.
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Not many of these things survive in space either, especially in a relatively stable corner of the universe like ours. They've either been ground up in star or planet formation or swept up by bigger objects rather like this one has been by earth. For it to also then fall onto earth intact is exceptionally rare.
 
Invictus said:
Conventional astrochemical wisdom would dictate that it hasn't actually been on Earth for a significant amount of time, hence the relative lack of erosion — maybe it is cosmic debris that originated in another star system and was whimsically floating around in space before succumbing to the Earth's gravitational field, maybe it is a relic of our Sun's primordial accretion disc that landed on Earth in the recent past, or some other predictive theory.

There are much older meteorites on Earth as well, like fragments of the one that fell in Murchison, Australia — which are estimated * to be older than the Solar System itself!




* The estimates can vary a bit — from a minimum of ~4 billion years to a maximum of ~7 billion years.
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I find it unlikely it came from another star system, given the distances involved. It's much more likely that it is a remnant of the protoplanetary disc, it could even be ejecta from an early protoplanet in the same orbit plane as Earth; particularly considering it has already been subjected to differentiation. I would probably say that's most likely to be the case.

Edit: for it to have come from another star system, I imagine it would have had to have been ejected by gravitational forces from a massive planet or ejected during a T-Tauri phase. Though for it to be the latter, unless the material pre-dates the new star, it's unlikely to have undergone differentiation. At least to my knowledge, I could be wrong!
 
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Another Starlink launch. I do miss the old matter-of-fact NASA commentator on these launches instead of the overexcited teenagers they seem to employ now.


You have to give Musk credit, for all his bluff and bluster he has created an incredibly reliable LEO delivery system with the Falcon 9 series. 1 failure in 113 launches is well beyond anything else to date.
 
Photographer Spends 12 Years, 1250 Hours, Exposing Photo of Milky Way

Finnish astrophotographer J-P Metsavainio has released a Milky Way photo that took him nearly 12 years to create. The 1.7-gigapixel image has a cumulative exposure time of 1,250 hours.​
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Metsavainio began shooting for the project back in 2009. For the next 12 years, he focused on different areas and objects in the Milky Way, shooting stitched mosaics of them as individual artworks. To complete the ultra-high-resolution view of the Milky Way as a whole, Metsavainio then set out to fill in the gaps that weren’t covered by his original artworks.​
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“I think this is a first image ever showing the Milky Way in this resolution and depth at all three color channels (H-a, S-II, and O-III),” Metsavainio tells PetaPixel.​
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The photo is 100,000 pixels wide and comprises 234 individual panels stitched together.​

https://petapixel.com/2021/03/16/ph...years-1250-hours-exposing-photo-of-milky-way/
 
The Firestarter said:
I am eager to find out . I read it has these dust tornadoes, but probably the rover is trained to GTF-O in case it spots one.
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They're called dust devil's and one case of a rover that couldn't move because of dust on its solar panels, was helped by a dust devil. It blew over the rover and cleaned the dust off the panel so it could move again.
 
giggs-beckham said:
They're called dust devil's and one case of a rover that couldn't move because of dust on its solar panels, was helped by a dust devil. It blew over the rover and cleaned the dust off the panel so it could move again.
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Yeah this rover doesn't need solar panels.
 
calodo2003 said:
Of course it does. Very groovy. What’s the anticipated lifespan of the battery? Years?
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I guess it depends on how much plutonium they used, I don't really know exactly beyond the basics, but yeah we're talking decades. The rover will probably be switched off or become inoperable before the battery depletes.
 
calodo2003 said:
Of course it does. Very groovy. What’s the anticipated lifespan of the battery? Years?
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That'sHernandez said:
I guess it depends on how much plutonium they used, I don't really know exactly beyond the basics, but yeah we're talking decades. The rover will probably be switched off or become inoperable before the battery depletes.
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The prime mission is for a minimum of 2 years but the battery should be good for at least 14 years.
 
The Firestarter said:
Not so cool if you get a catastrophic launch failure with such payload. Apart from that, very convenient.
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There's not enough fuel present to cause a major problem, about 5kg in total. They calculated the maximum exposure from the worst accident would be little over 6 months worth of background radiation.
 
11101 said:
There's not enough fuel present to cause a major problem, about 5kg in total. They calculated the maximum exposure from the worst accident would be little over 6 months worth of background radiation.
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Well sometimes shit really happens.



Think this one caused nuclear / chemical contamination too.
 
The Firestarter said:
Well sometimes shit really happens.



Think this one caused nuclear / chemical contamination too.
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That was an old Proton rocket carrying 3 satellites, no nuclear fuel involved.

It's decades since any nuclear fuel was shed in a space related accident and even then it had minimal impact. I'm not saying it couldn't happen again but the containment systems are far better now, and any effect would be reasonably small. Perseverance has 4.8kg of nuclear fuel onboard. The 3 reactors at Fukushima had 300 tons.
 
11101 said:
That was an old Proton rocket carrying 3 satellites, no nuclear fuel involved.

It's decades since any nuclear fuel was shed in a space related accident and even then it had minimal impact. I'm not saying it couldn't happen again but the containment systems are far better now, and any effect would be reasonably small. Perseverance has 4.8kg of nuclear fuel onboard. The 3 reactors at Fukushima had 300 tons.
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The models they use account for atmospheric detonation and then you can indeed regard it as increased bg radiation. My point was that sometimes land crashes due to happen (or straight up T=0 explosions) and then what you get is a plutonium dirty bomb - one of the most unpleasant elements in vaporized form. Not only you will be making this launchpad unusable for a while, but it will harm the immediate response to the emergency in that area.
 
The Firestarter said:
The models they use account for atmospheric detonation and then you can indeed regard it as increased bg radiation. My point was that sometimes land crashes due to happen (or straight up T=0 explosions) and then what you get is a plutonium dirty bomb - one of the most unpleasant elements in vaporized form. Not only you will be making this launchpad unusable for a while, but it will harm the immediate response to the emergency in that area.
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That's why these launchpads are miles from anywhere. If there was to be a launch explosion a dirty bomb wouldn't do much beyond the immediate area; it's far different than a fission bomb.
 
11101 said:
That's why these launchpads are miles from anywhere. If there was to be a launch explosion a dirty bomb wouldn't do much beyond the immediate area; it's far different than a fission bomb.
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39B is 3 miles to Kennedy Space center. And 8 miles to an air force station which I think was their main concern if something happened during the first minute.

I am fully aware of the fundamental differences between the various nuc devices mate.
 
Just to play Devil's advocate. Getting to 5 sigma is seen as a breakthrough, statistically.

The LHC reported a "diphoton anomaly" with a sigma of around 4 sigma six years ago which turned out to be noise.
The Brookhaven data from 2001 had a sigma of 3.7.
The new Fermilab data by itself is 3.3 sigma.
You only get to 4.2 sigma by combining both the Brookhaven and new Fermilab data.

Can you combine old data with new like that? Surely if there's a flaw in the former, it's still present in the latter?

The video says the estimation of chance for 4.2 sigma is 1/100,000, but the press release claims 1/40,000. Which is it?

Why not get to 5 Sigma (1 in 3.5 million), then announce?

I don't like early announcements. Perhaps because I remember this.
 
Invictus said:



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On the first listen, I found this all too complex.
But listening to it again, it still seems highly complex but I now understand the statical part a bit more. More and more data will eventually tell us whether the anomaly is real or not.
Isn't physics fantastic.
 
Counterfactual said:
Just to play Devil's advocate. Getting to 5 sigma is seen as a breakthrough, statistically.

The LHC reported a "diphoton anomaly" with a sigma of around 4 sigma six years ago which turned out to be noise.
The Brookhaven data from 2001 had a sigma of 3.7.
The new Fermilab data by itself is 3.3 sigma.
You only get to 4.2 sigma by combining both the Brookhaven and new Fermilab data.

Can you combine old data with new like that? Surely if there's a flaw in the former, it's still present in the latter?

The video says the estimation of chance for 4.2 sigma is 1/100,000, but the press release claims 1/40,000. Which is it?

Why not get to 5 Sigma (1 in 3.5 million), then announce?

I don't like early announcements. Perhaps because I remember this.
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To be fair, it's not conclusive either way on that Martian meteorite. I get the wider point though.
 
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