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Author Topic: Astronomical news  (Read 14548 times)

b_lumenkraft

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Re: Astronomical news
« Reply #100 on: July 07, 2019, 03:35:53 PM »
This one blew my mind.

Are Alien Civilizations Sending Signals in Bacteria? with Dr. Robert Zubrin


gerontocrat

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Re: Astronomical news
« Reply #101 on: July 07, 2019, 04:29:13 PM »
This one blew my mind.

Are Alien Civilizations Sending Signals in Bacteria? with Dr. Robert Zubrin

If they are, they are even dumber than wot we is.
"Para a Causa do Povo a Luta Continua!"
"And that's all I'm going to say about that". Forrest Gump
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b_lumenkraft

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Re: Astronomical news
« Reply #102 on: July 07, 2019, 04:33:33 PM »
LOL! ;D ;D ;D

pikaia

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Re: Astronomical news
« Reply #103 on: July 07, 2019, 05:01:41 PM »

kassy

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Re: Astronomical news
« Reply #104 on: July 07, 2019, 06:09:25 PM »
Cool!

Regarding the bacteria you would have to send generalized bacteria everywhere which precludes adding extra info and you cannot really edit stuff when you do not know what is there.

The mind was blown by the colorfulness of the theory?
Þetta minnismerki er til vitnis um að við vitum hvað er að gerast og hvað þarf að gera. Aðeins þú veist hvort við gerðum eitthvað.

SteveMDFP

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Re: Astronomical news
« Reply #105 on: July 07, 2019, 07:04:56 PM »
Cool!

Regarding the bacteria you would have to send generalized bacteria everywhere which precludes adding extra info and you cannot really edit stuff when you do not know what is there.

The mind was blown by the colorfulness of the theory?

It strikes me as quite plausible that life was seeded across the galaxy, possibly naturally, possibly intentionally.  A life form could use amino acids of the D-isomer variety, but all life here uses L isomers.  Similar handedness preference applies to sugar molecules.  All life here uses the C-A-T-G alphabet for DNA coding, but other "languages" are perfectly feasible.

If life arose on Earth in multiple places, one might expect descendants to have competing alphabet systems.  There's no sign of that today. 

As mirror-image building blocks would likely have toxic effects on consumers of plant life, any eater of plants (or higher on the food chain) would have trouble surviving.  Only those having the same "language" as plants would likely survive.  But why should today's plants be uniform?  Either life arose only once (or maybe a few times), or the planet was seeded with organisms having our currently universal "language."

It's quite remarkable that some life forms (e.g., tardigraves) are well-adapted to survive in space, and resume life functions when in a suitable environment.  Why should evolution favor such traits?

kassy

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Re: Astronomical news
« Reply #106 on: July 07, 2019, 09:49:49 PM »
All life that evolved here came from the same source so that is why they are uniform, they have a shared ancestor somewhere.

Chemical mirroring is very different from processes like matter antimatter destruction.
Þetta minnismerki er til vitnis um að við vitum hvað er að gerast og hvað þarf að gera. Aðeins þú veist hvort við gerðum eitthvað.

uniquorn

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Re: Astronomical news
« Reply #107 on: July 11, 2019, 09:18:47 PM »
Marine scientists at the Woods Hole Oceanographic Insti­tution who explore Earth’s hydrothermal vents have been working with NASA to devise autonomous underwater vehicles that could work on both Earth and Europa. The agency just announced a $7.6 million, five-year collaboration with WHOI to have space and ocean researchers brainstorm the science and technology needed for future Europa missions.

https://www.wired.com/story/forget-the-moon-we-should-go-to-jupiters-idyllic-europa/

b_lumenkraft

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Re: Astronomical news
« Reply #108 on: July 11, 2019, 09:30:32 PM »
Wow, that's great! \o/

b_lumenkraft

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Re: Astronomical news
« Reply #109 on: July 13, 2019, 01:28:51 PM »
Quote
Today (July 11), the Hayabusa2 spacecraft performed a 2nd touchdown on the surface of asteroid Ryugu. The touchdown occurred at 10:06 JST at the onboard time and was successful. Below we show images taken before and after the touchdown. As this is a quick bulletin, more detailed information will be given in the future.
Link >> http://www.hayabusa2.jaxa.jp/en/topics/20190711e_PPTD_ImageBulletin/

vox_mundi

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Re: Astronomical news
« Reply #110 on: July 22, 2019, 05:57:22 PM »
Astronomers Map Vast Void In Our Cosmic Neighborhood
https://phys.org/news/2019-07-astronomers-vast-void-cosmic-neighborhood.html



An astronomer from the University of Hawaiʻi Institute for Astronomy (IfA) and an international team published a new study that reveals more of the vast cosmic structure surrounding our Milky Way galaxy.



“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

vox_mundi

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Re: Astronomical news
« Reply #111 on: July 25, 2019, 05:12:33 PM »
India Farmers Shocked as 15 kg Meteorite Crashes into Rice Paddy
https://phys.org/news/2019-07-india-farmers-meteorite-rice-field.html
https://timesofindia.indiatimes.com/city/patna/15kg-meteorite-crashes-into-madhubani-paddy-field/articleshow/70351611.cms

MADHUBANI/PATNA: Farmers working in a paddy field at a village in Madhubani district were left shaken when a meteorite-like object weighing around 15kg fell from the sky, leaving a crater at the spot where it crashed.

Madhubani DM Shirsat Kapil Ashok told TOI that the incident took place around 2.30pm on Monday. “Agriculture labourers working the paddy field where the meteorite struck claimed that they saw a fireball-like object coming down from the sky and made a deep crater where it hit the ground. The farmers also saw smoke coming out from the spot in the water-filled agriculture field,” Shirsat said.



--------------------------

Researchers Seeking Fragments of Fireball in Ontario
https://phys.org/news/2019-07-fragments-fireball-ontario.html

Researchers are seeking the public's help in locating fragments of a fireball that shone as bright as the full moon observed by Western's All-Sky Camera Network across at 2:44 a.m. ET this morning.

Initial analysis of the video data by Steven Ehlert at the NASA Meteoroid Environment Office suggests the recent meteorite fragments are likely to have fallen to the ground near Bancroft, Ont.

"This fireball likely dropped a small number of meteorites in the Bancroft area, specifically near the small town of Cardiff. We suspect meteorites made it to the ground because the fireball ended very low in the atmosphere just to the west of Bancroft and slowed down significantly. This is a good indicator that material survived," Brown said.



---------------------------------

Cosmic Pearls: Fossil Clams in Florida Contain Evidence of Ancient Impact
https://phys.org/news/2019-07-cosmic-pearls-fossil-clams-florida.html

Researchers picking through the contents of fossil clams from a Sarasota County quarry found dozens of tiny glass beads, likely the calling cards of an ancient meteorite.

Analysis of the beads suggests they are microtektites, particles that form when the explosive impact of an extraterrestrial object sends molten debris hurtling into the atmosphere where it cools and recrystallizes before falling back to Earth.

They are the first documented microtektites in Florida and possibly the first to be recovered from fossil shells.



Open Access: Mike Meyer et al, A first report of microtektites from the shell beds of southwestern Florida, Meteoritics & Planetary Science (2019)

----------------------------------

An Asteroid Just Missed Earth, and We Barely Noticed in Time
https://phys.org/news/2019-07-asteroid-earth.html

A 100-metre-wide asteroid passed just 70,000km from Earth on Thursday, Australian time. It was discovered by the Brazilian SONEAR survey just days ago, and its presence was announced mere hours before it zoomed past our planet. The lack of warning shows how quickly potentially dangerous asteroids can sneak up on us.

The asteroid, reassuringly designated 2019 OK, is not a threat to Earth right now. However, 2019 OK and other near-Earth asteroids do pose a genuine risk.

Both 2019 OK and Apophis are far larger than the Chelyabinsk meteor, which was just 20m across. The risk of them hitting Earth may be small, but they would be devastating if they did.

Other near-Earth asteroids are also on track to make close approaches to our planet. The 400m-wide Apophis will pass roughly 30,000km from Earth on Friday April 13, 2029, which will only come as bad news if you're particularly superstitious.

“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

SteveMDFP

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Re: Astronomical news
« Reply #112 on: July 25, 2019, 05:58:21 PM »
India Farmers Shocked as 15 kg Meteorite Crashes into Rice Paddy
https://phys.org/news/2019-07-india-farmers-meteorite-rice-field.html

Not too surprising.  We are in the midst of the annual meteor peak:

MAJOR METEOR SHOWERS
https://www.amsmeteors.org/meteor-showers/major-meteor-showers/

"June to mid-July has fair rates. The last half of July has rates increasing steadily as the Delta Aquariids (July 29/30) and Alpha Capricornids (July 27-28) have maxima at month’s end. Even the Perseids are beginning to show a little.

Overall, late July to mid-August is very rich in meteors. The Perseid maximum, just before mid-August (August 12/13), is fairly prolonged and quite rich."


So, if meteorology is the study of weather, what is the study of meteors?

vox_mundi

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Re: Astronomical news
« Reply #113 on: July 31, 2019, 09:31:04 PM »
TESS Satellite Uncovers 'First Nearby Super-Earth'
https://phys.org/news/2019-07-tess-satellite-uncovers-nearby-super-earth.html

An international team of astronomers led by Cornell's Lisa Kaltenegger has characterized the first potentially habitable world outside of our own solar system.

Located about 31 light-years away, the super-Earth planet—named GJ 357 d—was discovered in early 2019 owing to NASA's Transiting Exoplanet Survey Satellite (TESS), a mission designed to comb the heavens for exoplanets, according to their new modeling research in the Astrophysical Journal Letters.

"This is exciting, as this is humanity's first nearby super-Earth that could harbor life.

The exoplanet is more massive than our own blue planet, and Kaltenegger said the discovery will provide insight into Earth's heavyweight planetary cousins. "With a thick atmosphere, the planet GJ 357 d could maintain liquid water on its surface like Earth, and we could pick out signs of life with telescopes that will soon be online," she said.



R. Luque et al. Planetary system around the nearby M dwarf GJ 357 including a transiting, hot, Earth-sized planet optimal for atmospheric characterization, Astronomy & Astrophysics (2019)
“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

Gumbercules

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Re: Astronomical news
« Reply #114 on: August 04, 2019, 07:34:37 PM »
India Farmers Shocked as 15 kg Meteorite Crashes into Rice Paddy
https://phys.org/news/2019-07-india-farmers-meteorite-rice-field.html
https://timesofindia.indiatimes.com/city/patna/15kg-meteorite-crashes-into-madhubani-paddy-field/articleshow/70351611.cms


Lol, meteorites of that size don't smoke. If anything they would be ICE cold. Meteorites of that size go through something called a dark phase, after they stop ionizing the air around them because they are slow enough for that to stop. Unless the rock is HUGE, the fireball phase stops miles up.

During entry through the atmosphere, the parts of the rock that get hut, ablate away, and that carries away almost all of the heat of re-entry. The interior is of the temperature it was when it was in space. So likely very cold.

Rod

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Re: Astronomical news
« Reply #115 on: August 08, 2019, 05:50:49 AM »
Well ...... That was unfortunate! 😝

A CRASHED ISRAELI LUNAR LANDER SPILLED TARDIGRADES ON THE MOON

Quote
IT WAS JUST before midnight on April 11 and everyone at the Israel Aerospace Industries mission control center in Yehud, Israel, had their eyes fixed on two large projector screens. On the left screen was a stream of data being sent back to Earth by Beresheet, its lunar lander, which was about to become the first private spacecraft to land on the moon. The right screen featured a crude animation of Beresheet firing its engines as it prepared for a soft landing in the Sea of Serenity. But only seconds before the scheduled landing, the numbers on the left screen stopped. Mission control had lost contact with the spacecraft, and it crashed into the moon shortly thereafter.

Quote
Half a world away, Nova Spivack watched a livestream of Beresheet’s mission control from a conference room in Los Angeles. As the founder of the Arch Mission Foundation, a nonprofit whose goal is to create “a backup of planet Earth,” Spivack had a lot at stake in the Beresheet mission. The spacecraft was carrying the foundation’s first lunar library, a DVD-sized archive containing 30 million pages of information, human DNA samples, and thousands of tardigrades, those microscopic “water bears” that can survive pretty much any environment—including space.

Quote
But when the Israelis confirmed Beresheet had been destroyed, Spivack was faced with a distressing question: Did he just smear the toughest animal in the known universe across the surface of the moon?

Quote
In the weeks following the Beresheet crash, Spivack pulled together the Arch Mission Foundation’s advisers in an attempt to determine whether the lunar library had survived the crash. Based on their analysis of the spacecraft’s trajectory and the composition of the lunar library, Spivack says he is quite confident that the library—a roughly DVD-sized object made of thin sheets of nickel—survived the crash mostly or entirely intact. In fact, the decision to include DNA samples and tardigrades in the lunar library may have been key to its survival.

“For the first 24 hours we were just in shock,” Spivack says. “We sort of expected that it would be successful. We knew there were risks but we didn’t think the risks were that significant.”

https://www.wired.com/story/a-crashed-israeli-lunar-lander-spilled-tardigrades-on-the-moon/

SteveMDFP

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Re: Astronomical news
« Reply #116 on: August 08, 2019, 04:17:10 PM »
Well ...... That was unfortunate! 😝

A CRASHED ISRAELI LUNAR LANDER SPILLED TARDIGRADES ON THE MOON
 

Tardigraves, and a few other identified organisms, have a mind-boggling ability to survive dehydration, vacuum, radiation, and extreme cold.  Their existence is part of why I favor panspermia as an explanation for life on earth.

However, they weren't released into deep space, where they might eventually find their way to Proxima Centauri (or wherever), they were deposited on the moon.  "Daytime the temperature can reach 260 degrees Fahrenheit (127 degrees Celsius)."  Poor little water bears will be cooked.

crandles

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Re: Astronomical news
« Reply #117 on: August 08, 2019, 05:00:10 PM »


However, they weren't released into deep space, where they might eventually find their way to Proxima Centauri (or wherever), they were deposited on the moon.  "Daytime the temperature can reach 260 degrees Fahrenheit (127 degrees Celsius)."  Poor little water bears will be cooked.

maybe not quite cooked?

https://www.google.com/search?q=tardigrades+temperature+survival&oq=tartigrades+temperature&aqs=chrome.1.69i57j0l3.12403j0j7&sourceid=chrome&ie=UTF-8
Quote
They can survive a wide range of temperatures and situations. Research has found that tardigrades can withstand environments as cold as minus 328 degrees Fahrenheit (minus 200 Celsius) or highs of more than 300 degrees F (148.9 C), according to Smithsonian magazine.

SteveMDFP

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Re: Astronomical news
« Reply #118 on: August 08, 2019, 05:10:56 PM »


maybe not quite cooked?

https://www.google.com/search?q=tardigrades+temperature+survival&oq=tartigrades+temperature&aqs=chrome.1.69i57j0l3.12403j0j7&sourceid=chrome&ie=UTF-8
Quote
They can survive a wide range of temperatures and situations. Research has found that tardigrades can withstand environments as cold as minus 328 degrees Fahrenheit (minus 200 Celsius) or highs of more than 300 degrees F (148.9 C), according to Smithsonian magazine.

Dang, the little beasts are even tougher than I realized.  They just need to be kicked to lunar escape velocity by some meteorite, and next stop is Proxima Centauri!!  (in maybe a million years or so).

crandles

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Re: Astronomical news
« Reply #119 on: August 08, 2019, 06:29:01 PM »
IIUC, we have revived them after 10 years of dehydration but not longer. While techniques might improve, after 100 years of high radiation, I think chances of revival would be low and natural revival after randomly arriving at some planet other than Earth with liquid water are remote enough.  ;) :D

More risk of Aliens visiting Earth and Moon and deciding that some long lost civilisation either worshipped such creatures for some unknown reason or decided they were the Earth species most worth attempting to save for prosperity.  ;)

Tor Bejnar

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Re: Astronomical news
« Reply #120 on: August 08, 2019, 08:26:38 PM »
Nicely said Crandles!  After getting the Strictly Germ-proof treatment, they may turn into some super-creature wherever they land, worthy of saving.
Arctic ice is healthy for children and other living things.

vox_mundi

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Re: Astronomical news
« Reply #121 on: August 14, 2019, 05:40:35 PM »
How Many Earth-Like Planets are Around Sun-Like Stars?
https://phys.org/news/2019-08-earth-like-planets-sun-like-stars.html

... Based on their simulations, the researchers estimate that planets very close to Earth in size, from three-quarters to one-and-a-half times the size of earth, with orbital periods ranging from 237 to 500 days, occur around approximately one in four stars. Importantly, their model quantifies the uncertainty in that estimate. They recommend that future planet-finding missions plan for a true rate that ranges from as low about one planet for every 33 stars to as high as nearly one planet for every two stars.



Danley C. Hsu et al. Occurrence Rates of Planets Orbiting FGK Stars: Combining Kepler DR25, Gaia DR2, and Bayesian Inference, The Astronomical Journal (2019)
“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

blumenkraft

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Re: Astronomical news
« Reply #122 on: August 14, 2019, 08:20:32 PM »
So, where is everybody?
“You are not entitled to your opinion. You are entitled to your informed opinion. No one is entitled to be ignorant.”

Renerpho

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Re: Astronomical news
« Reply #123 on: August 14, 2019, 08:34:23 PM »
A 100-metre-wide asteroid passed just 70,000km from Earth on Thursday, Australian time. It was discovered by the Brazilian SONEAR survey just days ago, and its presence was announced mere hours before it zoomed past our planet. The lack of warning shows how quickly potentially dangerous asteroids can sneak up on us.

While approaches like that of 2019 OK are quite a routine occurrence (happening many times per year with no consequence), this one had some unusual characteristics. It revealed some flaws with our asteroid detection systems, which have already led to changes made by the big asteroid surveys. I wrote about it here: https://www.quora.com/How-did-we-miss-detecting-asteroid-2019-OK/answer/Daniel-Bamberger-1
Before I came here I was confused about this subject. Having listened to your lecture I am still confused. But on a higher level.

SteveMDFP

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Re: Astronomical news
« Reply #124 on: August 14, 2019, 08:43:58 PM »
So, where is everybody?

Probably in quite a few places.  But possibly the other intelligent species hadn't evolved with hands.  It's hard to develop an industrial civilization with only paws or tentacles or flippers.

petm

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Re: Astronomical news
« Reply #125 on: August 14, 2019, 09:25:00 PM »
Don't you guys read? They're everywhere!  ;D

https://en.wikipedia.org/wiki/List_of_reported_UFO_sightings

blumenkraft

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Re: Astronomical news
« Reply #126 on: August 14, 2019, 09:56:24 PM »
But possibly the other intelligent species hadn't evolved with hands.  It's hard to develop an industrial civilization with only paws or tentacles or flippers.

Yes, one perfectly fine answer to the Fermi paradox. We are missing us in time.

But then there is the big number of possibilities and you start thinking again...
“You are not entitled to your opinion. You are entitled to your informed opinion. No one is entitled to be ignorant.”

Renerpho

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Re: Astronomical news
« Reply #127 on: August 14, 2019, 10:13:17 PM »
Yes, one perfectly fine answer to the Fermi paradox. We are missing us in time.

But then there is the big number of possibilities and you start thinking again...

My favourite solution to the Fermi paradox was given by Terry Bisson, in his short story "They're Made Out of Meat".
The universe is full of intelligent species, but the aliens find us so disgusting, they have decided to forget about humanity, and marked the Solar System "unoccupied".

https://en.wikipedia.org/wiki/They%27re_Made_Out_of_Meat

Before I came here I was confused about this subject. Having listened to your lecture I am still confused. But on a higher level.

Grubbegrabben

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Re: Astronomical news
« Reply #128 on: August 14, 2019, 10:34:40 PM »
But possibly the other intelligent species hadn't evolved with hands.  It's hard to develop an industrial civilization with only paws or tentacles or flippers.

Yes, one perfectly fine answer to the Fermi paradox. We are missing us in time.

But then there is the big number of possibilities and you start thinking again...

The lower probability, an earth-like planet in 1 out of 33 star systems, yields about 3 billion earth-like planets in our galaxy...

Even if there are a million explorers out there that travel at near light speed, they will only look in our solar system once every 15-50 000 years or so (avg distance between stars is 5 light years, 3 billion places to look, yes my calculation is probably wrong).

The number of possibilities is so large that another intelligent spieces out there is very likely. However, the vastness of space makes it unlikely to meet them anytime soon. A bit sad, who wouldn't like to shake the flipper or tentacle of another species?

petm

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Re: Astronomical news
« Reply #129 on: August 14, 2019, 10:46:24 PM »
There's a lot more than size and sun distance that may be required for life to evolve. Water. Magnetosphere. Even our unusual (large, close-in) moon may have had an important role (tides). Just to name a few.

Earth has only just evolved a species capable of interstellar communication. Say, ~100 years / 5 billion years of Earth's existence. And we've almost wiped ourselves out already with nukes, and here comes global environmental devastation... Seems to me that the great filter is highly plausible.

https://en.wikipedia.org/wiki/Great_Filter

oren

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Re: Astronomical news
« Reply #130 on: August 15, 2019, 04:46:18 AM »
So, where is everybody?
So obvious IMHO. They ran out of their planet's finite resources and/or polluted it to extinction, before they managed to create a true spacefaring civilization.
The Fermi paradox is not a paradox, but a warning that humanity disregards.

Renerpho

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Re: Astronomical news
« Reply #131 on: August 15, 2019, 04:52:36 AM »
<snip>
https://en.wikipedia.org/wiki/Great_Filter

Kurzgesagt have made an interesting video about the Great Filter. If you don't know their Youtube channel, it's worth checking out. The idea they present in this video is that the discovery of alien life would spell doom for our own - for reasons that are not at all obvious...

Before I came here I was confused about this subject. Having listened to your lecture I am still confused. But on a higher level.

TerryM

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Re: Astronomical news
« Reply #132 on: August 15, 2019, 01:06:08 PM »
So, where is everybody?
So obvious IMHO. They ran out of their planet's finite resources and/or polluted it to extinction, before they managed to create a true spacefaring civilization.
The Fermi paradox is not a paradox, but a warning that humanity disregards.
Ramen!
We quite recently polluted the moon with lifeforms - and we haven't even set up an outpost!
We're a filthy species that will die in our own pollution. :-[
Terry

budmantis

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Re: Astronomical news
« Reply #133 on: August 17, 2019, 07:45:19 AM »
I wish that it was not so, but I have to agree with you Terry!

kassy

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Re: Astronomical news
« Reply #134 on: August 17, 2019, 09:30:25 AM »
A Massive Star Completely Destroyed by a Supernova is Puzzling Scientists

In November of 2016, the sharp-eyed Gaia spacecraft spied a supernova that exploded some billion light-years from Earth. Astronomers followed up with more telescopes, and quickly realized that this supernova – dubbed SN2016iet – was an odd one in many ways.

And this star was extremely massive, starting life as some 200 times the mass of the sun, near the upper limit of what scientists think is possible for a single star to weigh.

The supernova itself also left what appeared to be the signature of two explosions, separated by about 100 days. Astronomers think this isn’t actually due to multiple explosions, but from the explosion hitting different layers of material the star lost in the years leading up to its death and left scattered around it in a diffuse cloud.

The star meets many of the criteria for something called a pair instability supernova, a kind of explosion that some extremely massive stars should theoretically undergo. Such an event leaves the star completely destroyed, leaving nothing behind. But finding examples of these rare stellar explosions has been difficult, and this is still one of the first scientists have discovered. And even in that rare company, SN2016iet remains an oddball find.

and more on:
http://blogs.discovermagazine.com/d-brief/2019/08/16/a-massive-star-completely-destroyed-by-a-supernova-is-puzzling-scientists
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gandul

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Re: Astronomical news
« Reply #135 on: August 17, 2019, 09:45:09 PM »
So, where is everybody?
So obvious IMHO. They ran out of their planet's finite resources and/or polluted it to extinction, before they managed to create a true spacefaring civilization.
The Fermi paradox is not a paradox, but a warning that humanity disregards.
Ramen!
We quite recently polluted the moon with lifeforms - and we haven't even set up an outpost!
We're a filthy species that will die in our own pollution. :-[
Terry
I did not come for the astronomy, but sir, please, cheer up! We can colonize Siberia, Sahara, and the North American Southwest without polluting more than we already pollute. Plus, there's oxygen and we do not need CO2 increasing rockets.
No me lo trago

vox_mundi

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Re: Astronomical news
« Reply #136 on: August 21, 2019, 05:02:30 PM »
A Step Closer to Solving Methane Mystery on Mars
https://phys.org/news/2019-08-closer-methane-mystery-mars.html

Last year, scientists learned that methane concentrations changed over the course of the seasons with a repeatable annual cycle.

"This most recent work suggests that the methane concentration changes over the course of each day,"
Dr. Moores said.

"We were able—for the first time—to calculate a single number for the rate of seepage of methane at Gale crater on Mars that is equivalent to an average of 2.8 kg per Martian day."

Dr. Moores said the team was able to reconcile the data from the ExoMars Trace Gas Orbiter and the Curiosity Rover, which appeared to contradict each other with wildly different detections of methane.

"We were able to resolve these differences by showing how concentrations of methane were much lower in the atmosphere during the day and significantly higher near the planet's surface at night, as heat transfer lessens," he said.

John E. Moores et al. The methane diurnal variation and micro‐seepage flux at Gale crater, Mars as constrained by the ExoMars Trace Gas Orbiter and Curiosity observations, Geophysical Research Letters (2019)

--------------------

Abstract
The upper bound of 50 parts per trillion by volume (pptv) for Mars methane above 5 km established by the ExoMars Trace Gas Orbiter, substantially lower than the 410 pptv average measured overnight by the Curiosity Rover, places a strong constraint on the daytime methane flux at the Gale crater. We propose that these measurements may be largely reconciled by the inhibition of mixing near the surface overnight whereby methane emitted from the subsurface accumulates within meters of the surface before being mixed below detection limits at dawn. A model of this scenario allows the first precise calculation of micro‐seepage fluxes at Gale to be derived, consistent with a constant 1.5 x 10‐10 kg m‐2 sol (5.4 x 10‐5 tonnes km‐2 year‐1) source at depth. Under this scenario, only 2.7 x 104 km2 of Mars’ surface may be emitting methane, unless a fast destruction mechanism exists.

Key Points
- Night‐time SAM‐TLS seasonal cycle enrichment measurements and TGO sunset/sunrise measurements are not in opposition
- Micro‐seepage fluxes must be local to Gale, range from 0.82 to 4.6 kg per sol, and are consistent with a constant source at depth
- Little of Mars experiences micro‐seepage unless a fast destruction mechanism exists or Gale is very unusual


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vox_mundi

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Re: Astronomical news
« Reply #137 on: August 30, 2019, 12:47:51 AM »


This animated flyover of each of the four candidate sample collection sites on asteroid Bennu, selected by NASA's OSIRIS-REx asteroid sample return mission, was produced using close-range data from the OSIRIS-REx Laser Altimeter (OLA), an instrument contributed by the Canadian Space Agency. It illustrates the location of each site on Bennu, the topography of each site, and the potential sampling regions that the spacecraft will target, which are 10 meters in diameter.
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blumenkraft

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Re: Astronomical news
« Reply #138 on: September 01, 2019, 03:29:28 PM »
The pulse of the gas thrusters on SpaceX's Falcon 9, as the rocket's boost stage guides it back to Earth

via reddit/r/space

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kassy

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Re: Astronomical news
« Reply #139 on: September 08, 2019, 06:59:16 PM »
Not news per se but a sundays light reading suggestion:

Are We All Wrong About Black Holes?

A philosopher of science worries that the analogy between black holes and thermodynamics has been stretched too far.

https://www.wired.com/story/are-we-all-wrong-about-black-holes/

I think he makes some strong points.

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sidd

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Re: Astronomical news
« Reply #140 on: September 08, 2019, 08:48:32 PM »
I was disappointed to find the wired interview with callender did not touch upon Jacobson's work in deriving GR from thermo/stat mech.

sidd

vox_mundi

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Re: Astronomical news
« Reply #141 on: September 08, 2019, 09:18:41 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

sidd

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Re: Astronomical news
« Reply #142 on: September 09, 2019, 05:58:49 AM »
I looked at the qunta article, found no mention of jacobson.

Here is his 1995 paper deriving the Einstein equation as an equation of state (like Boyle's law)

"it may be no more appropriate to canonically quantize the Einstein equation than it would be to quantize the wave equation for sound in air."

"For sufficiently high sound frequency or intensity one knows that the local equilibrium condition breaks down, entropy increases, and sound no longer propagates in a time reversal invariant manner. Similarly, one might expect that sufficiently high frequency or large amplitude disturbances of the gravitational field would no longer be described by the Einstein equation, not because some quantum operator nature of the metric would become relevant, but because the local equilibrium condition would fail. It is my hope that, by following this line of inquiry, we shall eventually reach an understanding of the nature of “non-equilibrium spacetime”."

https://arxiv.org/abs/gr-qc/9504004

And here he is from 2015 on entanglement entropy and the Einstein equation , also on arxiv but i dont have the reference handy

"Entanglement Equilibrium and the Einstein Equation"

sidd

vox_mundi

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Re: Astronomical news
« Reply #143 on: September 11, 2019, 07:47:44 PM »
First Water Detected on Potentially 'Habitable' Planet
https://phys.org/news/2019-09-potentially-habitable-planet.html



K2-18b, which is eight times the mass of Earth, is now the only planet orbiting a star outside the Solar System, or 'exoplanet', known to have both water and temperatures that could support life.

The discovery, published today in Nature Astronomy, is the first successful atmospheric detection for an exoplanet orbiting in its star's 'habitable zone', at a distance where water can exist in liquid form.

... The planet orbits the cool dwarf star K2-18, which is about 110 light years from Earth in the Leo constellation. Given the high level of activity of its red dwarf star, K2-18b may be more hostile than Earth and is likely to be exposed to more radiation.

Co-author Dr. Ingo Waldmann (UCL CSED), said: "With so many new super-Earths expected to be found over the next couple of decades, it is likely that this is the first discovery of many potentially habitable planets. This is not only because super-Earths like K2-18b are the most common planets in our Galaxy, but also because red dwarfs—stars smaller than our Sun—are the most common stars."
“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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philopek

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Re: Astronomical news
« Reply #144 on: September 11, 2019, 10:56:13 PM »
First Water Detected on Potentially 'Habitable' Planet


This is still interesting don't get me wrong, but this kind of info belongs to any mention of so called "earth-like" exoplanets.

IMO this kind of exoplanet is not even worth to mention in the context of finding "Earth II" or habitability. It's clearly NOT habitable because it's obvious for several reasons that it is not suitable for the kind of life we're ultimately looking for and habitable means "FOR US HUMANS" and not for germs and bacteria etc.

It takes way more than the right temps and then gravitation eight times earth level would crush all things we know are necessary for intelligent and/or human life.

A planet so close to it's sun cannot even considered inside the habitable zone, despite perhaps the right temps.

Further planets that are to close to their sun usually stopped rotating long ago and therefore would have very small band of "right" temps while the rest would be burning or freezing and in the process produce extremely strong winds, way beyond what we consider strong on planet earth.

And what you said, radiation without being protected due to lack of magnetic field due to lack of rotation etc. etc.

vox_mundi

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Re: Astronomical news
« Reply #145 on: September 11, 2019, 11:35:59 PM »
Do Super-Earths Trap the Civilizations On Them?
https://www.psychologytoday.com/us/blog/world-wide-mind/201211/do-super-earths-trap-the-civilizations-them

Super-Earths are massive, but that doesn't mean their gravity is crushing. In fact, bigger planets may be even better for space travel than Earth is.

... the formula for calculating a planet’s surface gravity: mass divided by the radius squared. That is, SG=M/R^2.

Let’s try it with HD 40307g, using data from the Habitable Exoplanet Catalog. Mass, 8.2 Earths. Radius, 2.4 times that of Earth. That gets you a surface gravity of 1.42 times Earth.

It seems counterintuitive, doesn’t it? How can a planet be so much more massive than Earth yet have only 1.42 times the gravity at the surface? The answer lies in the radius. The further you are from the planet’s center, the less its gravity pulls at you. Another way of putting it is that the greater the planet’s radius is for its mass, the less dense it is.

So it’s all about the radius.

That just leaves tornado-like winds and UV & radiation from flares. Which may not be a 'given'

It doesn't follow that a tidally-locked planet would not have a magnetic field. If anything, it would have a very strong field.

Exoplanet, Mass, Radius, Surface Gravity

Gliese 581g    2.60   1.4   1.33

Gliese 581d    6.90   2.2  1.43

Gliese 667Cc  4.90  1.9   1.36

Kepler 22b      6.40   2.1   1.45

HD40307g      8.20   2.4    1.42

HD85512b      4.00    1.7    1.38

Gliese 163c    8.00    2.4    1.39

Fictional Planet 8.00  2.83   1.00

Escape velocity, however, would be higher.

It’s a function of both mass and size. If Fictional Planet was four times Earth’s mass and had two Earth radii, its surface gravity would still be 1g, but you’d need to go only 41% faster to get away from it permanently.

Surface gravity and escape velocity are both related to size and mass, but differently. Fictional Planet would be just as comfortable as Earth in terms of gravity, but more expensive to leave.

Far from being gravitational traps, super-Earths should be positive incubators of spacefaring civilizations. They have 8 times the resources.
“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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gandul

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Re: Astronomical news
« Reply #146 on: September 11, 2019, 11:46:15 PM »
First Water Detected on Potentially 'Habitable' Planet


This is still interesting don't get me wrong, but this kind of info belongs to any mention of so called "earth-like" exoplanets.

IMO this kind of exoplanet is not even worth to mention in the context of finding "Earth II" or habitability. It's clearly NOT habitable because it's obvious for several reasons that it is not suitable for the kind of life we're ultimately looking for and habitable means "FOR US HUMANS" and not for germs and bacteria etc.

It takes way more than the right temps and then gravitation eight times earth level would crush all things we know are necessary for intelligent and/or human life.

A planet so close to it's sun cannot even considered inside the habitable zone, despite perhaps the right temps.

Further planets that are to close to their sun usually stopped rotating long ago and therefore would have very small band of "right" temps while the rest would be burning or freezing and in the process produce extremely strong winds, way beyond what we consider strong on planet earth.

And what you said, radiation without being protected due to lack of magnetic field due to lack of rotation etc. etc.
Agree to your comment (well 8 times earth mass does not imply 8g at surface).
But I think water is important.
Problem with Mars, water is not there in quantities, so why don’t we colonize Sahara? As hard but no need of space travel...
If we cannot even fill Sahara with massive viable solar energy plants...
Billionaire dreams ... space travel.
No me lo trago

vox_mundi

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Re: Astronomical news
« Reply #147 on: September 12, 2019, 12:46:47 AM »
Have Astronomers Just Spotted Another Interstellar Object?
https://gizmodo.com/have-astronomers-just-spotted-another-interstellar-obje-1838052026

An amateur astronomer named Gennady Borisov first spotted the object on August 30, using a telescope he built himself. Other observations (and hype) have followed. Today, the Minor Planet Center at the Center for Astrophysics released an official circular on the object, now provisionally called C/2019 Q4 (Borisov). If scientists confirm its interstellar nature, it will receive a new name that begins with 2I, denoting it as the second interstellar object.

... Initial observations already reveal that the object is an active comet with a big temporary atmosphere, or coma, Holman said.

“Absent an unexpected fading or disintegration, this object should be observable for at least a year,” according to the circular.

https://minorplanetcenter.net/mpec/K19/K19RA6.html
“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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blumenkraft

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Re: Astronomical news
« Reply #148 on: September 12, 2019, 08:36:56 AM »
this object should be observable for at least a year,

Hmmm, a very slow interstellar object, meaning it's traveling somehow in the same direction than our solar system, right?

That would be amazing!


No, it's not. :)

Link >> https://www.projectpluto.com/temp/gb00234.htm
« Last Edit: September 13, 2019, 09:01:57 AM by blumenkraft »
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vox_mundi

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Re: Astronomical news
« Reply #149 on: September 13, 2019, 05:41:17 PM »
Newly Discovered Comet is Likely Interstellar Visitor
https://phys.org/news/2019-09-newly-comet-interstellar-visitor.html



The comet is currently 260 million miles (420 million kilometers) from the Sun and will reach its closest point, or perihelion, on Dec. 8, 2019, at a distance of about 190 million miles (300 million kilometers).

Currently on an inbound trajectory, comet C/2019 Q4 is heading toward the inner solar system and will enter it on Oct. 26 from above at roughly a 40-degree angle relative to the ecliptic plane. That's the plane in which the Earth and planets orbit the Sun.

"The comet's current velocity is high, about 93,000 mph [150,000 kph], which is well above the typical velocities of objects orbiting the Sun at that distance," said Farnocchia. "The high velocity indicates not only that the object likely originated from outside our solar system, but also that it will leave and head back to interstellar space."

Observations completed by Karen Meech and her team at the University of Hawaii indicate the comet nucleus is somewhere between 1.2 and 10 miles (2 and 16 kilometers) in diameter.
“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