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Space... the final frontier...

...here's something to look forward to within the next 6 months... China's Tiangong-1 Space Station is about to fall to Earth so remember to 'duck' once you hear a strange noise from above... lol!... from this website below... cheers.

http://www.popularmechanics.com/space/news/a28633/chinas-space-station-will-deorbit-by-april/
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China's Space Station Will Crash into Earth by April 2018

China lost control of the station last year, and it's expected to enter the atmosphere within the next six months.


1493829828-tiangong-2-shenzhou-11-complex.jpeg


Last year, China decommissioned its first space station, Tiangong-1, bringing its astronauts back to Earth. The plan was to gradually allow the station to deorbit, eventually bringing it down in a controlled descent over an ocean. But somewhere along the way, things went wrong, and China irreparably lost control of its station back in September of last year.

At the altitude where Tiangong-1 was placed, there's almost no atmosphere, so it took a long time for the station to lose the first few miles of altitude. But now it's much lower, and there's a good chance that the station will fall back to Earth sometime within the next six months.

"Now that [its] perigee is below 300km and it is in denser atmosphere, the rate of decay is getting higher," said astrophysicist Jonathan McDowell to The Guardian. "I expect it will come down a few months from now – late 2017 or early 2018."

It's nearly impossible to predict exactly when the station will come down, however. A lot depends on atmospheric currents and the exact speed and orientation of the satellite. The precise direction of the station and how much it's rotating are going to determine how quickly it slows down, and those factors are impossible to know or predict.

"Even a couple of days before it re-enters we probably won't know better than six or seven hours, plus or minus, when it's going to come down," says McDowell.

When it does finally come down, the station will break apart in the atmosphere and mostly disintegrate before it reaches the surface. Still, there's a chance pieces as large as 200 pounds could make it to the ground.

Luckily, the Earth is mostly water, and large population centers are spread thin, so there's a very small chance that someone will get hit. There have been a few uncontrolled station reentries in the past—most famously Skylab, which came down over the Australian outback and earned NASA a $400 fine for littering—but none of those have ever caused injuries or property damage.

Still, it can't hurt to look up every so often. Perhaps you'll see a space station deorbiting overhead.
 
...more on that Chinese Space Station above... and any other Space objects flying overheard for that matter... from this website below...

http://www.n2yo.com/?s=37820

...it shows the orbit of the doomed Tiangong-1 which skims along Australia's top end but as they say... it is out of control...the website has the info 'Live' so that you know as to where it is at all times... here is a screenshot of the page...


2017-10-15_11-42-15.jpg

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2017-10-15_11-56-40.jpg

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...it really is a good website because you can put in the name of any satellite and it shows you where it is in orbit at any time... you can also get 'Live streaming' of cloud cover from the ISS Space Station... it's brilliant!... cheers.
 
...an update on China's falling Space Station Tiangong-1... from this website below... cheers.

https://www.businessinsider.com.au/chinese-space-station-when-it-will-crash-2017-10?r=US&IR=T

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China's first space station is doomed -- but objects inside of it may reach the ground unharmed

Dave Mosher
Oct 19, 2017

Wikimedia CommonsA solar flare.


Launched in September 2011, China’s first space station — Tiangong-1 — will soon burst into a fiery rain of debris over Earth.
As reported by The Guardian, China recently told the United Nations that it expects Tiangong-1 to reenter our atmosphere and crash by early 2018.

When it does, extreme heat and pressure caused by ploughing through the air at more than 24,000km/h will destroy most of the 8.5-tonne spacecraft.

But Bill Ailor, an aerospace engineer and atmospheric reentry specialist, says there’s a chance gear and hardware left could survive intact due to Tiangong’s onion-like layers of protective material.

“The thing about a space station is that it’s typically got things on the inside,” Ailor, who works for the Aerospace Corporation, a nonprofit research and development center, told Business Insider.

“So basically, the heating will just strip these various layers off,” he added. “If you’ve got enough layers, a lot of the energy is gone before a particular object falls out, it doesn’t get hot, and it lands on the ground.”

When NASA’s Columbia space shuttle broke up over the US, for example, he said a working flight computer was recovered that helped explain how the deadly incident happened.

How the sun could make Tiangong-1 crash sooner
China’s “Heavenly Palace” Tiangong-1 space station is 60 times smaller by volume than the International Space Station. It was superseded in 2016 by a follow-up Chinese space station, Tiangong-2.

However, China and experts alike hail it as a major achievement for the nation’s space program, since it served as a prototype toward establishing a permanent Chinese presence in space.

“It conducted six successive rendezvous and dockings with spacecraft Shenzhou-8, Shenzhou-9 and Shenzhou-10 and completed all assigned missions, making important contributions to China’s manned space exploration activities,” according to a note China submitted in June 2017 to the UN Committee on the Peaceful Uses of Outer Space.

Yet China said it lost contact with the spacecraft on March 16, 2016, after it “had fully fulfilled its historic mission.”

As of May 2017, Tiangong-1 was in an orbit about 350km above Earth but was dropping by some 175 metres per day, according to China. Its orbital altitude has since dropped to about 290km above Earth, according to The Guardian.

China expects its space station to reenter Earth’s atmosphere and be destroyed “between October 2017 and April 2018,” according to a UN memo.

“For any vehicle like this, the thing that brings them down is atmospheric drag,” Ailor said. “Why there’s a lot of uncertainty in the predictions is that it depends on what’s the sun’s doing to a large measure.”

The sun can unleash solar storms and solar flares — bursts of X-rays and ultraviolet light — that heat Earth’s outer atmosphere. This heating causes the air to expand, rise higher above the planet, and force low-flying objects like Tiangong-1 to plough through denser gases.

“This puts just a little bit of a higher force on these objects that causes them to come down,” Ailor said.

When and where China’s space station might crash

Ailor said he doesn’t think a crash of Tiangong-1 is imminent, but added that it’s very difficult to predict when an out-of-control object in space will reenter Earth’s atmosphere and break apart due to the sun’s activity.

“But if you look at the range of predictions that have been made, it’s been gradually moving earlier in time,” he said. “People are speculating anywhere from the end of this month until sometime in January or February of early next year.”

Business Insider asked NASA for comment on reentry forecasts for Tiangong-1, as well as whether the spacecraft posed a threat to any ongoing missions.

“We’re not commenting on this piece of hardware coming in. NASA actually doesn’t track any debris,” a space agency spokesperson told Business Insider.

He then directed us to contact the US Strategic Command’s Joint Space Operations Center — the military group that tracks space debris and lets NASA know if and when it poses a threat. JSpOC responded to our queries but did not provide an interview or comment in time for publication.

When Tiangong-1 does crash, it’s most likely to happen over the ocean, since water covers about 71% of Earth’s surface. But there’s a decent chance some pieces may strike land as it breaks up over a long and thin oval-shaped footprint.

“The whole footprint length for something like this could be 1,000 miles or so,” Ailor said.

He said pieces of the space station are “really unlikely” to hit anyone or anything.

“It’s not impossible, but since the beginning of the space age …. a woman who was brushed on the shoulder in Oklahoma is the only one we’re aware of who’s been touched by a piece of space debris.”

Should a hunk of titanium, an intact flight computer, or other pieces smash through a roof or windshield, however, international space law assures that victims will be compensated.

“It’s China’s responsibility if someone gets hurt or property gets damaged by this,” NASA’s spokesperson said.
 
Have you seen the simulated footage all over the place of the neutron collision?
Very cool:)

...I have kxk and no matter how old I get I'm still like a bewildered little child looking through a Telescope for the first time when it has anything to do with Space... it just so wonderous in it's magnificence to me... cheers.
 
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And your question about that avatar you asked in DW, is yes kind of...long ago

I have some photos of me and my sis I need help with, can I send you them in a PM and ask your advice please?

They are contact sheets photographers do, would like to isolate and enlarge some
 
And your question about that avatar you asked in DW, is yes kind of...long ago

I have some photos of me and my sis I need help with, can I send you them in a PM and ask your advice please?

They are contact sheets photographers do, would like to isolate and enlarge some

....why of course you can kxk... it would be my pleasure to try and help you out... just send them to me as you said and I will endeavour to help you as much as I can... I'm pretty clued up when it comes to things like that at times... feel free to PM me kxk... cheers.
 
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...an interesting little snippet from this website below... cheers.

http://www.news.com.au/technology/s...m/news-story/01471d1542f30509f701eeb65555d2eb
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Astronomers just found the first interstellar object from beyond our solar system
FOR the first time in history, a strange object from outside our solar system has been recorded zooming past the sun.

SCIENTISTS have been able to confirm a visitor from another part of the galaxy has entered our neck of the celestial woods.

Astrophysicist Brian Koberlein said the discovery was groundbreaking because never before has an interstellar object been observed within our solar system.

“We’ve known that some asteroids and comets could escape our solar system, through things like a close fly-by of Jupiter, and we’ve assumed a similar thing would occur in other star systems, but this confirms it,” he told Futurism.

“Some asteroids and comets become interstellar travellers, wandering through the stars and occasionally visiting a star.”

The strange space rock’s velocity and trajectory was key to understanding it was not from our solar system.

Scientists from the International Astronomical Union’s Minor Planet Center first thought it was a comet flung towards us from a neighbouring star, although additional data collected using the Very Large Telescope in Chile revealed that the object didn’t have any comet characteristics.

The fresh data saw MPC scientists reclassify the object as an asteroid dubbed A/2017 U1.

f003f905b37e9a6592d65a930110821e

Astronomers say that A/2017 U1 came from outside the solar system and is leaving again. Credit NASA/JPL-CaltechSource:Supplied

Travelling at 26 kilometres per second, the asteroid is moving too fast to be burned up by our sun or caught in its orbit, which means scientists are now racing to study the space rock before it leaves our galaxy.

Scientist at NASA’s Center for Near-Earth Object Studies Davide Farnocchia said A/2017 U1 had the most extreme orbit he had ever seen.

“It is going extremely fast and on such a trajectory that we can say with confidence that this object is on its way out of the solar system and not coming back,” he told Popular Science.

The asteroid’s now hurtling out of our star system towards the constellation Pegasus as a result of the sun’s gravity changing its course and speed.

“A/2017 U1 is already faint and fading quickly. We can still use large telescopes to track its position for a month or maybe two,” he said.

“The object may already be too faint for physical characterisation and measuring its size, mass or composition.”

Deputy Project Scientist of the James Webb Space Telescope Bonnie Meink said there was a lot to be learnt from the discovery.

“Observing ISOs [interstellar objects] in our solar system means we are probing the dynamics and formation of other solar systems. If these objects are getting kicked out of their home systems and into ours, we can learn about their home systems formation histories,” she said.

“This is similar to how planetary scientists learn about Mars by studying the Martian meteorites that hit Earth.”
 

...haha!... that was brilliant oddjob... I love it when little buried snippets like this arise every now and then... unknown mini historical facts like this make you realise just how much was at stake back then to be the FIRST in whatever certain nations were trying to achieve at that time lol!... thanks for posting that oddjob... cheers.
 
...I can't believe it... a day after your article oddjob this news snippet comes out... it's as if dog owners may have had their noses pushed out of joint and have posted this lol! (or Cat owners put out that article of yours to take the shine off this Historic event lol!)... either way... great feats on both sides lol!... from this website below... cheers.

https://www.gizmodo.com.au/2017/11/...-who-became-the-first-doggonaut-60-years-ago/

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Here's To The Brave Laika, Who Became The First Doggonaut 60 Years Ago

Jennings Brown
Nov 4, 2017, 3:00pm



On 3 November 1957, a street dog named Laika became the first Earthling to orbit our planet.

Photo: Getty

The Soviet Union had launched many good dogs into outer space before, but Laika became a global sensation because she was the first to enter low Earth orbit.

As The New Yorker wrote in its remembrance of the hero, the Soviet Union space program chose Laika because the mutt fit all the Soviet's doggonaut requirements at the time - she was scrappy enough to survive the rough streets of Moscow but colourful enough that she photographed well. The program also chose females because they were thought to be less temperamental than male dogs, and because it was more difficult to design suits that accommodated male canine genitalia.

Laika was bound into a crude spacesuit and loaded into Sputnik 2 a month after the spacecraft's predecessor became the first satellite launched into low Earth orbit. Ever a lover of dog puns, the United States press gave her the nickname Muttnick.


Photo: Getty

Many American animal lovers were horrified by the fate that awaited Laika. A few years later, President Dwight D. Eisenhower wrote of Laika in his memoir: "By a strange and compassionate turn, public opinion seemed to resent the sending of a dog to certain death - resentment that the Soviet propagandists tried to assuage, after it's death, by announcing that it had been comfortable to the end."

It seems unlikely that the dog was comfortable in her final moments. At the time the Soviet Government assured the concerned public that Laika was euthanised before death. But in 2002, one of Sputnik 2's scientists revealed that Laika died from overheating a few hours into the journey. The Soviet space program had been eager for good PR and only gave its engineers less than a month to build Sputnik 2, so there wasn't enough time to test the life-support system.

Laika's trainer, Adilya Kotovskaya, a Russian biologist, recently told Agence France-Presse of her remorse as she prepared to send Laika into space: "I asked her to forgive us and I even cried as I stroked her for the last time."

We hope that Laika enjoyed her brief moment soaring through the heavens before she perished. After the casket made 2570 orbits, she fell to the earth, a blaze of light above the Caribbean. Too good to return to this cruel world.
 
...this isn't exactly to do with Space (which is the prime topic of this thread) but it could be a trial run for say... Mars habitation for instance... I just love the fact that people are using old abandoned tunnels and air raid shelters and are putting them to use for a great reason too... from this website below... cheers.

http://www.abc.net.au/news/2017-11-...-wwii-air-raid-shelter-beneath-london/9118594

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WWII air raid shelter converted to grow food beneath London's streets

By Europe correspondent James Glenday



Photo: Plants are kept on stacks under LED lights in the converted WWII-era air raid shelters. (ABC: James Glenday)



The old lift creaks into life and we slowly descend 33 metres below the busy streets of Clapham in south London.

It is a journey thousands took to escape the bombs of Nazi Germany more than 70 years ago.

But unlike those who lived through that traumatic period, we are not greeted with austere bunk beds in long-dark tunnels.


Photo: This lift and stairwell offer no hints to the fascinating underground farm that lies below. (ABC: James Glenday)



When the lift opens, I'm handed a coat, a pair of boots and a few samples of salad in a room bathed in soft pink light.

"Down here we have leafy vegetables; so micro-herbs, radish, rocket, coriander," says Richard Ballard, the co-founder of Growing Underground, a pioneering urban farm that has made itself at home in this historic structure.

"We do it here with no natural light — using hydroponics and LED lights."

The produce goes to local restaurants, markets and grocers throughout London and the United Kingdom.

Customers appreciate the quirkiness of the enterprise and the relative reliability of the operation.


Photo: Conditions can be controlled to produce vegetables and herbs with consistent results. (ABC: James Glenday)



The long air-raid tunnels reportedly provide a "perfect environment" for this type of farm because the system of lights, dehumidifiers and fans allows the team to control the environment all year round.

"An above-ground farm will have natural variations in the light throughout the year," Mr Ballard says.

"Our system is consistent. Our temperature is constant."


Photo: Even the 'planting' of the seeds takes place in the underground facility. (ABC: James Glenday)



Mr Ballard struck on the idea of an underground farm after studying a film degree.

He and colleague Steven Dring, launched a crowd-funding campaign to make the operation a reality and it is now "nearly breaking even".

But if the original planners who built the air raid shelter had got their way, the scheme would have never existed.

The air-raid tunnels were made for trains, not tiny plants.


Photo: The seeds begin their journey far below Clapham's streets. (ABC: James Glenday)



"The [planners] had the amazing foresight to think of the use of them after the war," Mr Ballard says.

"They made them in a linear fashion so they could have an express northern [tube] line… but they didn't have the money to do it in the end".

As we chat there is the constant rumble of underground trains pulling into Clapham Common Station four levels above us.

"It's amazing how many spaces there are underground from nuclear bunkers to salt mines, there's a lot of space that could be used for this," Mr Ballard says.

"There is a real opportunity for this to happen in big cities where space is at a premium.

"[For instance,] car parks — as cars get less common, [there] could be another space being used like this."

The team hopes their urban farm in an historic air raid shelter is a peek into the not too distant future — a future where more food is grown closer to its source, using spaces most had forgotten.


Photo: Life above the underground farm carries on as usual. (ABC: James Glenday)
 
FLAT EARTHERS!!!!!!!!!!!
Actually still exist.......on Project now, how ridiculous.......they actually see space as from astronauts, space stations etc, all those pictures etc here.
What idiots, thinking anyone could be bothered doing all the work they claim to fake stuff
 
FLAT EARTHERS!!!!!!!!!!!
Actually still exist.......on Project now, how ridiculous.......they actually see space as from astronauts, space stations etc, all those pictures etc here.
What idiots, thinking anyone could be bothered doing all the work they claim to fake stuff

...for those that missed The Project like me last night here is that clip in it's entirety...

https://tenplay.com.au/channel-ten/the-project/extra/season-9/flat-earthers

...of course since I watched these loonies in the clip I have done some 'research' about these nuff nuffs and their websites etc... let's start with 'Judd Ditch'...

snapshot1.jpg
...he's a 'musician' and 'helps manage an online clothing store'... yup!... riiiiiiiiiight!!... he has 'Soundcloud/Youtube/ Instagram and Twitter accounts to promote his 'musical career' of course... surely he wouldn't be on The Project just to enhance his 'musical career' and to get some free TV exposure would he?... naaaaaah!... how cynical of me!... lol!...

...and then we have this other twonk that actually works with Satellites in his friggin' job!...

snapshot2.jpg

...his name is 'Brett Watkins' and he works for a 'telecommunications' company and once his bosses see this clip will NEVER receive a job promotion within the company again for embarrassing himself on National TV sure lol!... so what's his angle for trying to get his face on TV at all costs?... Tinder and dating websites not cutting it for you mate?... you'll NEVER get laid after that appearance sunshine!... what a buffoon!...

...and... as per my normal fervid investigations I have visited quite a few different websites chasing this idiocy up... I found this one to be a bit of fun... it is some former Astronauts giving some hilarious Tweets towards them lol!... here is the link...

https://www.techly.com.au/2017/10/1...rthers-hilariously-matter-fact-string-tweets/

...on the same page one of them talks about some rapper named K.N.o.B... oopsies!... that should read as B.o.B... that is trying to raise a million dollars to send up a rocket to prove that the Earth is flat but as someone says...

Looking at the campaign, you probably have the same questions I do:

Isn’t this clown famous? Can’t he afford to fund this himself? Why are people giving him money?

So far the campaign has raised a measly six thousand bucks, so B.o.B might have enough to buy a few of the weather balloons he plans to release in search of “evidence”.


Probably not enough for a satellite though.


According to this estimate, B.o.B is worth about $5 million.

Personally, I think he should spend it all on proving the Earth is flat. Maybe then he’ll disappear and we won’t have to listen to him.

...so yes 'B.o.B.'... why not just pay for it yourself old son?... oh I see... that way you don't get anymore publicity than you are at the moment of course... lol!... besides... if it does go up and proves to you that the Earth is round then it would shatter your enormous ego too wouldn't it?... and this website below...

https://www.livescience.com/24310-flat-earth-belief.html

...it is quite good reading actually because they talk about how 'Flatliners' explain how the Earth works according to them... (it's quite hysterical reading actually) lol!... here it is...

Earth's day and night cycle is explained by positing that the sun and moon are spheres measuring 32 miles (51 kilometers) that move in circles 3,000 miles (4,828 km) above the plane of the Earth. (Stars, they say, move in a plane 3,100 miles up.) Like spotlights, these celestial spheres illuminate different portions of the planet in a 24-hour cycle. Flat-earthers believe there must also be an invisible "antimoon" that obscures the moon during lunar eclipses.


Furthermore, Earth's gravity is an illusion, they say. Objects do not accelerate downward; instead, the disc of Earth accelerates upward at 32 feet per second squared (9.8 meters per second squared), driven up by a mysterious force called dark energy. Currently, there is disagreement among flat-earthers about whether or not Einstein's theory of relativity permits Earth to accelerate upward indefinitely without the planet eventually surpassing the speed of light. (Einstein's laws apparently still hold in this alternate version of reality.)

As for what lies underneath the disc of Earth, this is unknown, but most flat-earthers believe it is composed of "rocks."


upload_2017-11-9_16-34-35.jpeg


...there are a myriad of other sites whereas the 'Flatliners' garble on about their ridiculous bullshit such as these for example...

https://www.facebook.com/FlatEarthToday/

https://listverse.com/2016/02/01/10-absurd-claims-of-modern-flat-earth-conspiracy-theorists/

https://www.vice.com/en_uk/article/zngdg3/the-earth-is-flat-sam-kriss

...and there are some quite humorous video's of people debunking the 'Flat Earthers/Flatliners' theories like this one for instance...


...anyway... moving on... I have a couple of viewpoints of my own for the 'Flat Earthers/Flatliners' myself...

(1)... I believe that the people that start these websites up are Trollers that have been banned from every website that they have ever trolled and have all met one day and said to each other something like this...

..."hey!... we've all been banned from every website possible right?... we have nowhere to troll now right?... so!... I have an idea... why don't WE start our own website to do with something completely ridiculous like say?... oh I don't know?... um... let's say just for argument's sake that the Earth is really flat for example... and when people come on here to call us fuckwits or whatever then we can rip them to shreds lol!... the beauty of that is that we can't be banned from our own website!... WE'RE THE ADMINISTRATORS!... lol!... they are like fly's in our traps!... we can't lose!"...

...hence my theory of these websites... and...

(2)... as many would probably know... I'm not a religious man BUT!... I'd like to just say something in Religion's defense against these imbeciles that believe that the Earth is flat... most of the people that cannot answer certain questions on the subject often tell them to pray and read this or that scripture to answer the question for them so obviously they are quite religious people themselves... okay... that being said...

...they must believe that God created everything within the Universe and that He created Earth as a flat disc such as this right?...

2017-11-09_15-03-41.jpg

...so what gives them the right to underplay God's work by 'downsizing' all of his miraculous creations such as Galaxies/Nebula's/Planets/Suns and Moons down to a mere disc that is forever rising in the Universe?... aren't they merely trivialising his amazing creations?... how dare they take away his greatness of creations?... some really great work there yourselves 'Flat Earthers'... well done... you've just belittled your own God's ability at Creation itself... imbeciles!...

(3) Volcanoes erupt right?... where does the Lava flow from Earthliners?...

...anyhow... that's me done... these people are complete morons... anything for seeking attention types to me... if I went onto their websites to have some fun I'd be there for months arguing with them but then I'd be one of the Fly's in their trap... the trollers would be winning again on their home ground wouldn't they?... lol!... not for me I'm afraid lol!... I just couldn't be arsed lol!... **light-hearted rant over**... cheers.
 
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I am currently attending a talk about the cosmotology, the universe and the big bang by Brian Cox. It is confusing my brain but facinating!
 
I am currently attending a talk about the cosmotology, the universe and the big bang by Brian Cox. It is confusing my brain but facinating!

...oh wow Isee!... when you said 'attending a talk'... was you talking about seeing him in person in his show or something?... he's such a fascinating man who is only second to the late great Carl Sagan to me... I want to go to one of his Live shows one day myself... cheers.
 
...oh wow Isee!... when you said 'attending a talk'... was you talking about seeing him in person in his show or something?... he's such a fascinating man who is only second to the late great Carl Sagan to me... I want to go to one of his Live shows one day myself... cheers.
Yes he was live on stage in adelaide tonight. He raised lots of questions for my husband and I to ponder about the universe and the meaning of life and our place in it. So just light stuff for a Tuesday lol!
 
...Isee I so envy you and your husband... you lucky things you!... and needless to say that there were never any dull moments whatsoever lol!... what I like about him is that he has the same soothing voice when he speaks as Carl Sagan used to have and the way that they both explain things is so understandable to the common listeners that aren't overly clued up about all things to do with Space (including myself but I am learning every day)... as I said before Isee... he's on my 'to do' list in people that I want to see lol!... cheers.
 
...oh dear... it looks like just finding another Earth-like planet for us to live on and eventually destroy like this one isn't that easy to find afterall... apart from the immense distances involved in getting there in the first place... there is also the matter of finding the exact environmental ingredients to be able to keep us alive too apparently... (just a little suggestion from me folks... how about we just look after this Planet a little tad better in the first place eh?)... lol!... from this website below... cheers.

https://www.nature.com/news/exoplanet-hunters-rethink-search-for-alien-life-1.23023
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Exoplanet hunters rethink search for alien life
Astronomers expand ideas of how chemistry and geology could affect chances for life on other worlds.


2017_23NovNEWS_PlanetaryHabitability_800LEDE_NEW.jpg

M. Kornmesser/ESO
The exoplanet Ross 128b orbits a cool dwarf star at a distance that could allow the world to have liquid water.

Steve Desch can see the future of exoplanet research, and it’s not pretty. Imagine, he says, that astronomers use NASA’s upcoming James Webb Space Telescope to scour the atmosphere of an Earth-mass world for signs of life. Then imagine that they chase hints of atmospheric oxygen for years — before realizing that those were false positives produced by geological activity instead of living things.

Desch, an astrophysicist at Arizona State University in Tempe, and other planet hunters met from 13-17 November in Laramie, Wyoming, to plot better ways to scout for life beyond Earth. Many are starting to argue that the standard definition of habitability — having liquid water on a planet’s surface — is not the factor that should guide exoplanet exploration. Instead, the scientists say, the field should focus on the chances of detecting alien life, should it exist.

“Planets can be habitable and not have life with any impact,” Desch told researchers at the meeting.

It turns out that water worlds may be some of the worst places to look for living things. One study presented at the meeting shows how a planet covered in oceans could be starved of phosphorus, a nutrient without which earthly life cannot thrive. Other work concludes that a planet swamped in even deeper water would be geologically dead, lacking any of the planetary processes that nurture life on Earth.

“Habitability is not only about finding the signature of an alien life form taking a deep breath,” says Elizabeth Tasker, an astronomer and exoplanet researcher at the Japan Aerospace Exploration Agency's Institute for Space and Aeronautical Sciences in Sagamihara. It’s also about how a planet’s geology and chemistry interconnect to create a welcoming or hostile environment, she says — complicating the search for extraterrestrial life.

Surf and turf
Astronomers have catalogued thousands of exoplanets, of which more than a dozen are potentially habitable. The most recent, announced on 15 November, is Ross 128b, which is 3.4 parsecs (11 light years) away from Earth. It resembles the target that scientists have spent decades hunting: an Earth-sized planet orbiting a nearby star, probably at the right distance to allow liquid water.

Most of these planets have some qualities that stop them from being true Earth twins. Ross 128b orbits a cool dwarf star rather than a Sun-like host, for instance. But Tasker says the usual metrics that scientists use to rank how habitable a world is, such as its location relative to its star or how closely it resembles Earth, are misguided1.

To figure out how to parcel out valuable observing time, some scientists suggest targeting planets that, like Earth, are thought to have a mix of ocean and land. That's because worlds with nothing but water on their surfaces may not have key nutrients available in forms that can support life — if it is based on the same chemistry as life on Earth.

“We have this stereotype that if we have oceans, we have life,” says Tessa Fisher, a microbial ecologist at Arizona State. But her recent work contradicts this idea. Fisher and her colleagues studied what would happen on an “aqua planet” with a surface that is almost or completely covered by enough water to fill Earth’s oceans five times.

On Earth, rainwater hitting rocks washes phosphorus and other nutrients into the oceans. But without any exposed land, there is no way for phosphorus to enrich water on an aqua planet over time, Fisher reported at the Laramie meeting. There would be no ocean organisms, such as plankton, to build up oxygen in the planet’s atmosphere, she says — making this type of world a terrible place to find life.



Wet blanket
The wettest planets would run into a different sort of trouble, says Cayman Unterborn, a geologist at Arizona State who analysed the planet-wide effects of having as much as 50 Earth oceans’ worth of water. The sheer weight of all that liquid would exert so much pressure on the sea floor that the planet’s interior would not melt at all, Unterborn found.

Planets need at least some internal melting to sustain geological activity, such as plate tectonics, and to provide the right geochemical environment for life. In this case, Unterborn says, “too much water is too much of a good thing.”

Water-rich worlds are easy to make. Many planets are likely to have formed far from their parent star, Tasker says, in chilly temperatures where they could have coalesced from fragments of rock and lots of ice. If such a planet later migrated closer to its star, the ice would melt and cover the surface in vast oceans. Some of the seven small planets orbiting the star TRAPPIST-1, which is 12.6 parsecs (41 light years) from Earth, are thought to have substantial water on their surfaces2.

Instead of instinctively studying such water worlds, Tasker says, astronomers need to think more deeply about how planets have evolved through time. “We need to look carefully at picking the right planet,” she says.

The James Webb Space Telescope is set to launch in 2019. Once in space, the telescope will spend much of its time studying potentially Earth-like worlds. Researchers have already begun to analyse how oxygen, methane or other ‘biosignature’ gases in exoplanet atmospheres might appear to the telescope’s view3.

Towards the end of the Laramie meeting, attendees voted on whether scientists will find evidence of life on an exoplanet by 2040. They were not optimistic: 47 said no and 29 said yes. But a greater share was willing to bet that life would be found on another world in the 2050s or 2060s.

That's presumably enough time to work through the debate over which worlds are the best to target.
 
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