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Pmt111500

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Astronomical news
« on: November 17, 2018, 02:46:17 PM »
Thought "The Rest"-section of ASIF could use some science, astrometrical data has revealed a new companion galaxy to Milky Way, located on the far side, south of Vela constelllation. Very dim of course: https://www.sciencemag.org/news/2018/11/large-strangely-dim-galaxy-found-lurking-far-side-milky-way
« Last Edit: November 22, 2018, 02:05:59 PM by Pmt111500 »
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Pmt111500

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Re: Astronomical news
« Reply #1 on: November 22, 2018, 02:05:01 PM »
Couldn't find astronomy-thread so might use this thread for extraterrestrial news  8) ::). Just thought some might find it fun to read of other scientics than those related to climate. Similar threads for genetics, archeology, inorganic chemistry, medicine could be made here. The threads for science that is little to none related to climate change, that is. The wolf-rayet thread can be deleted so it won't be a single post thread.

Supernova candidate re-interpreted as potential gamma-ray burster by Aussie astronomers. The cone of the burst is not expected to hit earth:  https://sydney.edu.au/news-opinion/news/2018/11/20/doomed-star-in-milky-way-threatens-rare-gamma-ray-burst.html
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kassy

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Re: Astronomical news
« Reply #2 on: November 22, 2018, 03:12:05 PM »
We can either go with multiple threads or change the thread title to something more general and keep it in one thread.

I think Neven should pick because it is his site.  ;)

I do like your idea.

We found a new Tabbies-star like star:

stronomers Have Detected a New 'Alien Megastructure' Star, And It Might Give Us The Missing Answers

Between Earth and the galactic core, there's an old, faint star that appears to have something orbiting it, something that's confusing astronomers.

...

Astronomers first noticed VVV-WIT-07's odd periodic flickering during a 2012 survey of the inner Milky Way using the VISTA telescope in Chile. Now they're reporting their find, without being all that sure of what's causing it.

...

In 2012, VVV-WIT-07's amplitude was found to dim slowly for around 11 days, and then rapidly fade to next to nothing over the next 48 days.

The eclipse blocked a whopping 80 percent of the measured light, providing the astronomers with a real mystery. None of the usual explanations accounted for the eclipse.

...

The media attention might well come in handy, but Boyajian dismisses notions that alien ingenuity might be behind it.

"The new data shows that different colours of light are being blocked at different intensities," she said recently.

"Therefore, whatever is passing between us and the star is not opaque, as would be expected from a planet or alien megastructure."

That could mean it's a megastructure with tinted windows. Or maybe it's just time to let the idea go. Sorry.

and more on
https://www.sciencealert.com/a-new-alien-megastructure-has-been-found-and-it-might-soon-give-us-answers

BTW i like the last cited bit. I really dislike the idea of advanced alien societies building Dyson spheres.



Neven

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Re: Astronomical news
« Reply #3 on: November 22, 2018, 04:20:39 PM »
Thought "The Rest"-section of ASIF could use some science, astrometrical data has revealed a new companion galaxy to Milky Way, located on the far side, south of Vela constelllation. Very dim of course: https://www.sciencemag.org/news/2018/11/large-strangely-dim-galaxy-found-lurking-far-side-milky-way

Perfect, thanks!
Compare, compare, compare

Sleepy

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Re: Astronomical news
« Reply #4 on: November 22, 2018, 05:16:51 PM »
Since I don't use the "likes" I must say an honest thanks Pmt! A couple from the Unsorted thread:

Not sure where to put this.

COULD SOLAR RADIATION PRESSURE EXPLAIN ‘OUMUAMUA’S PECULIAR ACCELERATION?
https://arxiv.org/pdf/1810.11490.pdf
Alternatively, a more exotic scenario is that Oumuamua may be a fully operational probe sent intentionally to Earth vicinity by an alien civilization.

If it was, I can understand why they opted to step on it.

Icy 'Super-Earth' Exoplanet Spotted Around Nearby Barnard's Star
https://www.space.com/42423-barnards-star-super-earth-exoplanet-discovery.html
Quote
The nearest single star to the sun apparently hosts a big, icy planet.

Astronomers have found strong evidence of a frigid alien world about 3.2 times more massive than Earth circling Barnard's Star, a dim red dwarf that lies just 6 light-years from the sun. Barnard's Star is our sun's nearest neighbor, apart from the three-star Alpha Centauri system, which is about 4.3 light-years away.

The newly detected world, known as Barnard's Star b, remains a planet candidate for now. But the researchers who spotted it are confident the alien planet will eventually be confirmed.

"After a very careful analysis, we are 99 percent confident that the planet is there," Ignasi Ribas, of the Institute of Space Studies of Catalonia and the Institute of Space Sciences in Spain, said in a statement.
Omnia mirari, etiam tritissima.
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Science is a jealous mistress and takes little account of a man's feelings.

icefisher

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Re: Astronomical news
« Reply #5 on: November 23, 2018, 11:05:24 PM »
Changing light densities may indicate light being reflected by rings of ice crystals (similar to Saturn but much larger) prior to passage of a large gas giant 2-3 times the size of Jupiter.  Another possibility is a binary system with one of them being a young dim star.  Taking gravity, tilt, rotational speed, mass ... etc into account.  Lots and lots of possibilities.

Pmt111500

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Re: Astronomical news
« Reply #6 on: November 25, 2018, 02:55:45 PM »
One of the oldest stars found. According to some theories old stars were massive and short-lived, this star is way smaller than most population III stars yet found, so it presents some problems for some models of the early universe.
 http://www.astronomy.com/news/2018/11/red-dwarf-is-one-of-the-oldest-in-the-universe
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oren

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Re: Astronomical news
« Reply #7 on: November 25, 2018, 07:56:57 PM »
pmt, thanks for starting this thread and keeping us updated. It's not ASI or geophysical sciences, but it's interesting.

vox_mundi

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Re: Astronomical news
« Reply #8 on: November 26, 2018, 10:06:58 PM »
“There are three classes of people: those who see. Those who see when they are shown. Those who do not see.” ― Leonardo da Vinci

Insensible before the wave so soon released by callous fate. Affected most, they understand the least, and understanding, when it comes, invariably arrives too late

kassy

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Re: Astronomical news
« Reply #9 on: November 27, 2018, 02:39:43 PM »

magnamentis

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Re: Astronomical news
« Reply #10 on: November 27, 2018, 05:40:57 PM »
to all german speakers i recommend to to watch all those videos to get an idea:

https://www.br.de/mediathek/sendung/alpha-centauri-av:584f4cc13b467900117c476e

there are many more of those on the initial page, a great crash course in astronomy and astro-physics for noobs and those who love it always like myself, watching every night since 16 years LOL
http://magnamentis.com
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kassy

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Re: Astronomical news
« Reply #11 on: November 30, 2018, 03:48:51 PM »
Scientists Have Measured All the Photons Ever Produced in the Observable Universe

The team found that the amount of starlight, or the number of photons (particles of visible light) that stars have emitted throughout the history of the observable universe is 4×10^84 photons. Or, alternatively, 4,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,
000,000,000,000,000,000,000,000,000,000,000,000 photons.

http://blogs.discovermagazine.com/d-brief/2018/11/29/photons-starlight-universe-ever-produced


gerontocrat

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Re: Astronomical news
« Reply #12 on: November 30, 2018, 09:38:35 PM »
The team found that the amount of starlight, or the number of photons (particles of visible light) that stars have emitted throughout the history of the observable universe is 4×10^84 photons. Or, alternatively, 4,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,
000,000,000,000,000,000,000,000,000,000,000,000 photons.

Big universe, I found a figure for the observable universe volume as roughly 4×10^32 cubic light-years. Also a cubic light year is is a cube that is 10 trillion kilometers on each side. That is 8.23x10^38 cubic kilometers.
Life of the universe (so far)   13,800,000,000

Doing a bit of arithmetic says (if I got it right)

Photons emitted over life of the universe                                         4E+084
Size of observable universe in Km3                                               3.3E+071
Photons emitted over life of the universe per km3                12,150,668,286,756
Photons emitted over life of the universe per m3                                   12,151
Average Photons emitted per annum by the universe per km3                880
Average Photons emitted per annum by the universe per m3            0.00000088
   

Isn't the universe a dark place.
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kassy

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Re: Astronomical news
« Reply #13 on: December 05, 2018, 05:32:02 PM »
Dark matter mystery solved? Oxford University scientists may have solved one of the biggest questions in the universe

...

Dr Farnes suggests that both dark energy and dark matter are a fluid that possess "negative mass". That means in effect that it would be the inversion of normal mass: if you pushed it, it would be propelled towards you.

"We now think that both dark matter and dark energy can be unified into a fluid which possesses a type of 'negative gravity', repelling all other material around them," said Dr Farnes. "Although this matter is peculiar to us, it suggests that our cosmos is symmetrical in both positive and negative qualities."

That proposed fluid appears to work exactly as dark energy does.

"The outcome seems rather beautiful: dark energy and dark matter can be unified into a single substance, with both effects being simply explainable as positive mass matter surfing on a sea of negative masses," he said.


https://www.independent.co.uk/news/science/dark-matter-energy-solution-theory-negative-mass-astronomy-astrophysics-a8668476.html

Not sure if this will work but it would be nice to fill in the darks.

vox_mundi

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Re: Astronomical news
« Reply #14 on: December 05, 2018, 06:59:42 PM »
Add this to the Black Sea Deluge Hypothesis for scientific support of biblical myths.

Exploding Meteor 3,700 Years Ago, May Have Obliterated Communities Near the Dead Sea
https://phys.org/news/2018-12-meteor-air-years-obliterating-dead.html

Quote
A meteor that exploded in the air near the Dead Sea 3,700 years ago may have wiped out communities, killed tens of thousands of people, and provided the kernel of truth to an old Bible story. The area is in modern-day Jordan, in a 25 km wide circular plain called Middle Ghor. Most of the evidence for this event comes from archaeological evidence excavated at the Bronze Age city of Tall el-Hammam located in that area, which some scholars say is the city of Sodom from the Bible.

Archaeologists have been digging at the Tall el-Hamman site for 13 years, and have unearthed some pretty convincing evidence supporting the air-burst idea. The findings were presented on November 15th at the annual meeting of the American Schools of Oriental Research, by archaeologist Phillip Silvia of Trinity Southwest University.

Tall el-Hammam was a thriving city state occupying Middle Ghor. The civilization had occupied the area for over 2,500 years. The city itself held the administrative center of the kingdom, and was protected by a perimeter wall up to 30m (100 ft) thick and up to 15m (50 ft.) high, for a linear distance of over 2.5km. The wall held multiple gates, towers, and likely other defensive features. But all that was obliterated when the meteor pierced the atmosphere and exploded over the area.

Evidence gathered at the Tall el-Hammam site tells the story of the event. When the meteor air-burst occurred, there was an intensely hot and powerful shock wave. The shock wave wiped out all settlements in the area and destroyed an area of 500 sq. km. And the area remained uninhabited for a remarkable 700 years after the event. Several lines of evidence support the likelihood of this event.
Quote
Silvia and Collins say in their paper that the destruction and the damage on walls and other structures in the city is directional, supporting the idea of a shock wave. In the past, archaeologist have wondered if an earthquake could have caused the collapse of the region, but an earthquake would not have caused the type of directional damage that the remaining structures and fortifications display.

A pottery shard was found in the city that had one side melted to glass. Only extreme heat can do that. Examination revealed zircon crystals inside a bubble in the glass which could only have been formed by temperatures over 4000 Celsius. Additionally, the layer of melted clay that turned to glass is only 1 mm, not the entire depth of the shard. This indicates only a short burst of intense heat, rather than long exposure from something like burning petro-chemical eruptions. The research team concluded that the shard was exposed to temperatures between 8,000°C and 12,000°C for less than a few milliseconds. That certainly supports the idea of an airburst.

Signature markers of an airburst event include high levels of platinum, typically 600% above normal background levels, and a high platinum-palladium ratio. (Both of these occur in asteroids and meteors, but are not common on Earth.)

Researchers at the site also found what's called a "melt rock" weighing over 600 grams. It's an agglomeration of three different rocks melted together by extreme heat and covered with a layer of glass. This also contained zirconium crystals, and further analysis of the melt rock concluded that it had probably been exposed to 12,000 degree Celsius temperatures for a few seconds.


The final piece of evidence concerns what happened to the Tall el-Hammam area after the destruction. This region is considered the best-watered agricultural area in the region, yet after the Tall el-Hammam city-state was destroyed, the area remained unoccupied for about 700 years. What could have caused this, if the extreme heat from the air burst lasted only a few seconds?

The answer lies in the soil, according to the researchers. Six samples from above, through, and below the soil layer from the time of the event were analyzed geochemically. The results showed "salt and sulfate levels > 6 percent (60,000 ppm) in the ash layer and > 5 percent (50,000 ppm) in the soil layers immediately above and below the ash layer," according to the paper. The source of these contaminants had to be the Dead Sea, which borders the Middle Ghor area.

The two scientists say that the massive shockwave and heat wave not only destroyed the settlements, but the shock wave deposited a layer of salts onto the top soil, destroying it and making it unable to support agriculture for hundreds of years. It only takes a salt content of 12,800 ppm to prevent wheat from germinating, and a salt content of 17,900 ppm to prevent barley from growing. Those thresholds were easily exceeded.

The researchers concluded that an airburst with a yield equivalent to a 10 mt nuclear warhead occurred about 1 km above northeast corner of the Dead Sea. They say this adequately explains all of the evidence gathered at Tall el-Hammam.

Open Source: Steven Collins, Phillip Silvia, The Civilization-Ending 3.7KYrBP Event: Archaeological Data, Sample Analyses, and Biblical Implications.,

The Bible is interesting from a historical perspective, because it sometimes interweaves actual events from history with the Christian mythology. Now that it seems reasonable that a meteor airburst did destroy the area that may have contained Sodom, we can lay to rest the idea that the Christian God sent down fireballs to punish homosexuality. It looks like once again, it was a perfectly natural event that led to an apocalyptic, mythological story, and that what people once attributed to Gods and Goddesses is just nature.

And maybe god was really an alien that gave Lot the heads-up about some 'incoming' heading his way. Who knows?

also BBC: The Mystery Of The Egyptian Desert Glass - BBC Documentary


and https://en.wikipedia.org/wiki/Libyan_desert_glass
“There are three classes of people: those who see. Those who see when they are shown. Those who do not see.” ― Leonardo da Vinci

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SteveMDFP

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Re: Astronomical news
« Reply #15 on: December 05, 2018, 07:59:40 PM »
Dark matter mystery solved? Oxford University scientists may have solved one of the biggest questions in the universe
 

That proposed fluid appears to work exactly as dark energy does.

"The outcome seems rather beautiful: dark energy and dark matter can be unified into a single substance, with both effects being simply explainable as positive mass matter surfing on a sea of negative masses," he said.


https://www.independent.co.uk/news/science/dark-matter-energy-solution-theory-negative-mass-astronomy-astrophysics-a8668476.html

Not sure if this will work but it would be nice to fill in the darks.

Popular press never gets the explanations right.  The actual paper is here:
https://arxiv.org/abs/1712.07962

Seems completely bonkers.  Dark matter exhibits a kind of negative gravity here, repelling ordinary matter.  But nevertheless moves towards normal matter, because its motion is opposite to gravity.  It exerts a positive gravitational *force* on other dark matter, but direction of motion/acceleration is again opposite to that force. 

A theoretical dense dark matter object and ordinary object would accelerate in the same direction, without bound, by gravity.  Bonkers.




sidd

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Re: Astronomical news
« Reply #16 on: December 05, 2018, 09:33:56 PM »
Yes, negative mass is a wonderful thing, we covered this example in class many decades ago. The paper lays it out quite clearly.

"One of the more bizarre properties of negative mass is that which occurs in positive–negative mass particle pairs. If both masses have equal magnitude, then the particles undergo a process of runaway motion. The net mass of the particle pair is equal to zero. Consequently, the pair can eventually accelerate to a speed equal to the speed of light, c . Due to the vanishing mass, such motion is strongly subject to Brownian motion from interactions with other particles. In the alternative cases where both masses have unequal magnitudes, then either the positive or the negative mass may outpace the other – resulting in either a collision or the end of the interaction."

Heeheehee. I like it. I don't believe the paper will hold, but I like it.

sidd

pikaia

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Re: Astronomical news
« Reply #17 on: December 06, 2018, 09:54:45 AM »
A physicist talks about the hypothesis and its implications here:-

http://www.astronomyforum.net/astrophysics-forum/258999-new-theory-postulates-de-dm-same.html

kassy

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Re: Astronomical news
« Reply #18 on: December 06, 2018, 04:55:19 PM »
Not knowing what 96% of the universe is made of is kind of bonkers too.

We will see.

In this way mass is more like the other stuff with a positive and negative side and that makes sense on the idea level. Bit hard to think about because we only live in the positive side here.

PS: Nice summary by notFritz.


vox_mundi

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Re: Astronomical news
« Reply #19 on: December 06, 2018, 07:18:15 PM »
Quote
... There are more things in heaven and earth, Horatio, Than are dreamt of in your philosophy.
Shakespeare - Hamlet (1.5.167-8)

And yet Quantum Physics is bonkers relative to classical physics. Somehow I think we haven't exhausted all there is to know in physics  ...

Cosmologists Prove Negative Mass Can Exist In Our Universe
https://medium.com/the-physics-arxiv-blog/cosmologists-prove-negative-mass-can-exist-in-our-universe-250a980320a7

University of Rochester: Device Creates Negative Mass — and a Novel Way To Generate Lasers
http://www.rochester.edu/newscenter/vamivakas-microcavity-negative-mass-generate-lasers-290202/

Quote
University of Rochester researchers have succeeded in creating particles with negative mass in an atomically thin semiconductor, by causing it to interact with confined light in an optical microcavity.

... “By causing an exciton to give up some of its identity to a photon to create a polariton, we end up with an object that has a negative mass associated with it,” Vamivakas explains. “That’s kind of a mind-bending thing to think about, because if you try to push or pull it, it will go in the opposite direction from what your intuition would tell you.”

Other research groups have been experimenting with similar devices, Vamivakas says, but this is the first device to produce particles with negative mass.

The research was funded by the Air Force Research Laboratory.

https://www.nature.com/articles/nphys4303
“There are three classes of people: those who see. Those who see when they are shown. Those who do not see.” ― Leonardo da Vinci

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sidd

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Re: Astronomical news
« Reply #20 on: December 06, 2018, 10:00:08 PM »
I should note here that there are many examples of excitations which can have momentum in a different direction than (group) velocity. One famous example is rotons in liquid helium. Another is phonons in a crystal. But that takes us rather far afield.

sidd

Pmt111500

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Re: Astronomical news
« Reply #21 on: December 10, 2018, 07:20:42 PM »
Voyager 2 has exited heliosphere, reports NASA. The interstellar probe no longer observes the solar wind. Still, it's a very long way away from the gravitational borders of Sol System. The 41 years old, still working, instrument, that measures the energy and direction of the plasma particles hitting it, has noted the expected change in the direction as the galactic winds of particles start to hit it.

https://www.jpl.nasa.gov/news/news.php?release=2018-283
« Last Edit: December 10, 2018, 07:26:07 PM by Pmt111500 »
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vox_mundi

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Re: Astronomical news
« Reply #22 on: December 11, 2018, 06:05:56 PM »
Supernovae May Have Killed Off Large Ocean Animals at Dawn of Pleistocene
https://phys.org/news/2018-12-supernovae-large-ocean-animals-dawn.html

About 2.6 million years ago, an oddly bright light arrived in the prehistoric sky and lingered there for weeks or months. It was a supernova some 150 light years away from Earth. Within a few hundred years, long after the strange light in the sky had dwindled, a tsunami of cosmic energy from that same shattering star explosion could have reached our planet and pummeled the atmosphere, touching off climate change and triggering mass extinctions of large ocean animals, including a shark species that was the size of a school bus.

The effects of such a supernova—and possibly more than one—on large ocean life are detailed in a paper just published in Astrobiology.

A supernova 2.6 million years ago may be related to a marine megafaunal extinction at the Pliocene-Pleistocene boundary where 36 percent of the genera were estimated to become extinct. The extinction was concentrated in coastal waters, where larger organisms would catch a greater radiation dose from the muons.

Melott said recent papers revealing ancient seabed deposits of iron-60 isotopes provided the "slam-dunk" evidence of the timing and distance of supernovae.

"As far back as the mid-1990s, people said, 'Hey, look for iron-60. It's a telltale because there's no other way for it to get to Earth but from a supernova.' Because iron-60 is radioactive, if it was formed with the Earth it would be long gone by now. So, it had to have been rained down on us. There's some debate about whether there was only one supernova really nearby or a whole chain of them. I kind of favor a combo of the two—a big chain with one that was unusually powerful and close. If you look at iron-60 residue, there's a huge spike 2.6 million years ago, but there's excess scattered clear back 10 million years."

Melott said cancer and mutations would be the most obvious consequences for Earth's biology of a supernova's cosmic rays.

"There isn't a mass extinction, but there is kind of a lot of extinction going on at that time and species turnover," he said. "It's not quite severe enough to call it a mass extinction."

Adrian L. Melott et al, Hypothesis: Muon Radiation Dose and Marine Megafaunal Extinction at the End-Pliocene Supernova, Astrobiology (2018).


https://science.nasa.gov/science-news/science-at-nasa/2014/26aug_localbubble

According to the team, other evidence for a series of supernovae is found in the very architecture of the local universe.

"We have the Local Bubble in the interstellar medium," Melott said. "We're right on its edge. It's a giant region about 300 light years long. It's basically very hot, very low-density gas—nearly all the gas clouds have been swept out of it. The best way to manufacture a bubble like that is a whole bunch of supernovae blows it bigger and bigger, and that seems to fit well with idea of a chain. When we do calculations, they're based on the idea that one supernova that goes off, and its energy sweeps by Earth, and it's over. But with the Local Bubble, the cosmic rays kind of bounce off the sides, and the cosmic-ray bath would last 10,000 to 100,000 years. This way, you could imagine a whole series of these things feeding more and more cosmic rays into the Local Bubble and giving us cosmic rays for millions of years."
“There are three classes of people: those who see. Those who see when they are shown. Those who do not see.” ― Leonardo da Vinci

Insensible before the wave so soon released by callous fate. Affected most, they understand the least, and understanding, when it comes, invariably arrives too late