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Message 1926584 - Posted: 25 Mar 2018, 18:30:45 UTC
Last modified: 25 Mar 2018, 18:41:29 UTC

Anyone know what the size comparison of Tiangong-1 with Skylab?

What I found is Tiangong-1 is much smaller than Skylab..
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Message 1926602 - Posted: 25 Mar 2018, 20:32:09 UTC - in response to Message 1926584.  
Last modified: 25 Mar 2018, 20:33:41 UTC

Anyone know what the size comparison of Tiangong-1 with Skylab?
What I found is Tiangong-1 is much smaller than Skylab..

The weight of Skylab was 77 tonnes.
https://en.wikipedia.org/wiki/Skylab
Tiangong-1's weight is 8.5 tonnes.
https://en.wikipedia.org/wiki/Tiangong-1
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Message 1926603 - Posted: 25 Mar 2018, 20:34:18 UTC - in response to Message 1926602.  

Anyone know what the size comparison of Tiangong-1 with Skylab?
What I found is Tiangong-1 is much smaller than Skylab..

The weight of Skylab was 77 tonnes.
https://en.wikipedia.org/wiki/Skylab
Tiangong-1's weight is 8.5 tonnes.
https://en.wikipedia.org/wiki/Tiangong-1


Ta muchly :)
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Message 1926609 - Posted: 25 Mar 2018, 21:18:39 UTC - in response to Message 1926603.  

Anyone know what the size comparison of Tiangong-1 with Skylab?
What I found is Tiangong-1 is much smaller than Skylab..

The weight of Skylab was 77 tonnes.
https://en.wikipedia.org/wiki/Skylab
Tiangong-1's weight is 8.5 tonnes.
https://en.wikipedia.org/wiki/Tiangong-1

Ta muchly :)

As a comparision, IIS's weight is more than 420 tonnes and it will fall back to earth in about 2024 when the project shut down.
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Message 1926842 - Posted: 27 Mar 2018, 8:50:24 UTC

See China's space station death-dive live via telescope.

China's Tiangong-1 space station isn't long for this orbit.

Also known by its English translation, "Heavenly Palace," the out-of-control station is heading back into the atmosphere sometime around April 1. We don't know exactly when or exactly where it will reenter, but space fans will have a chance to watch one of its last passages across the sky live via telescope.

The Virtual Telescope Project, in partnership with Tenagra Observatories in Arizona, will broadcast a live online feed of the Heavenly Palace on Mar. 28 starting at 5 a.m. PT, though that time may be updated as needed. It's hard to predict the station's exact movements as its orbit decays.
Cheers.
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Message 1926960 - Posted: 28 Mar 2018, 21:44:31 UTC

Astronomers baffled by distant galaxy void of dark matter.

Astronomers have found a distant galaxy where there is no dark matter.

Dark matter is called "dark" because it can't be seen. It is the mysterious and invisible skeleton of the universe that scientists figure makes up about 27 percent of the cosmos. Scientists only know dark matter exists because they can observe how it pushes and pulls things they can see, like stars.

It's supposed to be everywhere.
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Message 1927055 - Posted: 29 Mar 2018, 11:03:24 UTC

Asteroid-bound spacecraft finds signs of life—on Earth by Katherine Kornei, Mar. 26, 2018
http://www.sciencemag.org/news/2018/03/asteroid-bound-spacecraft-finds-signs-life-earth

Nearly 30 years ago, the Galileo spacecraft flew past Earth on its journey to Jupiter, prompting astronomer Carl Sagan to develop a novel experiment: to look for signs of life on Earth from space. The spacecraft found high levels of methane and oxygen, suggestions that photosynthesis was occurring on Earth’s surface. Now, astronomers have repeated the experiment, this time with an asteroid-bound spacecraft that swung around Earth in late 2017. It also found Earth to be teeming with life, but with an unsettling corollary: Atmospheric levels of carbon dioxide and methane were far higher than they were during the Galileo flyby.

“It’s a challenging intellectual enterprise,” says Dante Lauretta, a planetary scientist at the University of Arizona in Tucson and principal investigator of NASA’s Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer (OSIRIS-REx) mission. “I really tried to channel Carl Sagan.”

(...) .
These OSIRIS-REx observations are an important test of what a habitable, life-filled planet looks like from afar, says Sarah Stewart Johnson, a planetary scientist at Georgetown University in Washington, D.C. “These images and spectra underscore the dazzling possibilities for exoplanets.” But as scientists begin to comb through observations from distant worlds for signs of life, they’ll want to remember some sage advice from the Galileo team: Any measurements that suggest the existence of life must always be carefully scrutinized for other possible explanations. As they wrote, “Life is the hypothesis of last resort.”

https://www.nasa.gov/osiris-rex
https://www.asteroidmission.org/
https://www.asteroidmission.org/why-bennu
https://solarsystem.nasa.gov/missions/galileo/in-depth/
Apr 3, 1999 - May 3, 2020
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Message 1927079 - Posted: 29 Mar 2018, 12:23:52 UTC - in response to Message 1927055.  

Searching for planets having atmospheric oxygen is good start to search for extraterrestrial life.
But it is a bit of a disappointment that oxygen in a planet's atmosphere does not have to be a sign of life.
http://www.manyworlds.space/index.php/2018/01/29/false-positives-false-negatives-the-world-of-distant-biosignatures-attracts-and-confounds/
The most often discussed biosignature is oxygen, the product of life on Earth. But while oxygen remains central to the search for biosignatures afar, there are some serious problems with relying on that molecule.
It can, for one, be produced without biology, although on Earth biology is the major source. Conditions on other planets, however, might be different, producing lots of oxygen without life.
And then there’s the troubling reality that for most of the time there has been life on Earth, there would not have been enough oxygen produced to register as a biosignature. So oxygen brings with it the danger of both a false positive and a false negative.
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Message 1927089 - Posted: 29 Mar 2018, 13:37:46 UTC

NASA's New Parker Probe Will Skim the Sun's Surface.

Early on Easter Sunday, around 4 am local time, a C-17 transport plane carrying a cargo worth $1.5 billion will take off from Joint Base Andrews near Washington, DC, and head south to Cape Canaveral. On board, a carefully wrapped and padded spacecraft headed for a rendezvous with the sun.

The Parker Solar Probe—designed and built by Johns Hopkins University’s Applied Physics Laboratory and managed by NASA—is scheduled to launch on July 31 aboard a Delta IV rocket. On its solar journey, it will reach speeds up to 450,000 miles per hour by using Venus’ gravitational pull as a slingshot. This speed will allow the probe to pass through the sun’s hazy atmosphere, or corona, at just 4 million miles above its surface—the closest a spacecraft has ever gotten to the fireball.
Cheers.
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Message 1927109 - Posted: 29 Mar 2018, 15:38:35 UTC - in response to Message 1927079.  
Last modified: 29 Mar 2018, 16:02:12 UTC

How can we avoid a 'false positive' for the detection of life on a planet, where oxygen is concerned? One way has been discussed scientifically. If both oxygen and methane are detected, the chances are much better that life is the source.

On an Earth-like planet, where we would be looking for life in the first place, the presence of methane suggests microorganisms, while oxygen hints at photosynthetic plants. The likelihood of both gases occurring together, exclusive of life is considered low.

As far as we know, only life can maintain a continuous supply of and ozone, an unstable form of oxygen, and methane, also unstable over time.
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Message 1927116 - Posted: 29 Mar 2018, 16:36:01 UTC

The European Space Agency has decided to build ARIEL, a spacecraft for analyzing the atmosphere of exoplanets. It should be launched in 2028.
Tullio
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Message 1927124 - Posted: 29 Mar 2018, 17:54:07 UTC - in response to Message 1927109.  
Last modified: 29 Mar 2018, 17:54:28 UTC

If both oxygen and methane are detected, the chances are much better that life is the source.

True.
But oxygen in gaseous form is very rare on celestial bodies like planets, moons and comets whereas methane is very common.
At very least in our solar system.

The likelihood of both gases occurring together, exclusive of life is considered low.
I don't think anyone can draw that conclusion.
Until the 90's no one even could say that exoplanets existed for certain.
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Message 1927131 - Posted: 29 Mar 2018, 18:42:12 UTC
Last modified: 29 Mar 2018, 18:50:10 UTC

#LiveTracking of the 8.5 metric tons uncontrolled #Tiangong1 Space Station atmospheric reentry
http://www.satflare.com/track.asp?q=37820#TOP
http://www.n2yo.com/?s=37820


Depending on the source, its reentry is predicted to happen sometime between saturday March 31 am and sunday April 1st pm EDT (UTC+5hrs).

ESA's reentry updates
http://blogs.esa.int/rocketscience/
Fraunhofer Institute for High Frequency Physics and Radar Techniques FHR
https://twitter.com/Fraunhofer_FHRe
#Tiangong1 Twitter feed:
https://twitter.com/search?q=%23Tiangong1&src=tyah
Chinese Space Station's Crash to Earth: Everything You Need to Know
https://www.space.com/40076-chinese-space-station-crash-to-earth-guide.html
https://en.wikipedia.org/wiki/Tiangong-1
Radar image video of #Tiangong1
https://twitter.com/Fraunhofer_FHRe/status/978616595609157635
Europe’s space freighter ATV Jules Verne burning up over an uninhabited area of the Pacific Ocean at the end of its mission (2008)
https://www.youtube.com/watch?v=OhBw5yaR_SU
Apr 3, 1999 - May 3, 2020
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Message 1927142 - Posted: 29 Mar 2018, 20:08:21 UTC

I just hope the Chinese don't try to take pot shots at it like they have done with previous satellites.
Bob DeWoody

My motto: Never do today what you can put off until tomorrow as it may not be required. This no longer applies in light of current events.
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Message 1927488 - Posted: 31 Mar 2018, 11:54:36 UTC
Last modified: 31 Mar 2018, 11:55:57 UTC

Tiangong-1 is currently predicted to reenter the Earth’s atmosphere around 23:25 UTC on 1 April, and running from the afternoon of 1 April to the early morning on 2 April. This remains highly variable.
http://blogs.esa.int/rocketscience/2018/03/26/tiangong-1-reentry-updates/
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Message 1927645 - Posted: 1 Apr 2018, 4:42:29 UTC

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Message 1927669 - Posted: 1 Apr 2018, 10:02:09 UTC - in response to Message 1927488.  

Update 1 April 2018

With the latest available orbital data and space-weather forecasts, the reentry prediction window has stabilised and shrunk further to a time frame running from midnight 1 April to the early morning of 2 April (in UTC time).

Tiangong-1 is currently predicted to reenter the Earth’s atmosphere around 23:25 UTC on 1 April, and running from the afternoon of 1 April to the early morning on 2 April. This remains highly variable.
http://blogs.esa.int/rocketscience/2018/03/26/tiangong-1-reentry-updates/

Apr 3, 1999 - May 3, 2020
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Message 1927781 - Posted: 2 Apr 2018, 1:41:07 UTC - in response to Message 1927669.  

China's Tiangong-1 space lab re-entered the Earth's atmosphere around 8.15 a.m. Monday (8:15 p.m. ET Sunday) in a fiery fall, China's Manned Space Agency said.
Tiangong-1 plummeted into the middle of the South Pacific, the space agency said.
"Most parts were burned up in the re-entry process," the agency said.
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Message 1928042 - Posted: 4 Apr 2018, 23:39:02 UTC

Center Of The Milky Way Has Thousands Of Black Holes, Study Shows.

The supermassive black hole lurking at the center of our galaxy appears to have a lot of company, according to a new study that suggests the monster is surrounded by about 10,000 other black holes.

For decades, scientists have thought that black holes should sink to the center of galaxies and accumulate there, says Chuck Hailey, an astrophysicist at Columbia University. But scientists had no proof that these exotic objects had actually gathered together in the center of the Milky Way.

"This is just kind of astonishing that you could have a prediction for such a large number of objects and not find any evidence for them," Hailey says.

He and his colleagues recently went hunting for black holes, using observations of the galactic center made by a NASA telescope called the Chandra X-ray Observatory.

Isolated black holes are almost impossible to detect, but black holes that have a companion — an orbiting star — interact with that star in ways that allow the pair to be spotted by telltale X-ray emissions. The team searched for those signals in a region stretching about three light-years out from our galaxy's central supermassive black hole.

"So we're looking at the very, very, very center of our galaxy. It's a place that's filled with a huge amount of gas and dust, and it's jammed with a huge number of stars," Hailey says.

What they found there: a dozen black holes paired up with stars, according to a report in the journal Nature.
Cheers.
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Message 1928267 - Posted: 6 Apr 2018, 7:01:57 UTC

Virgin Galactic conducts first rocket-powered test since 2014 crash.

Around 8 a.m., the company tweeted that mother ship VMS Eve and the attached VSS Unity had taken off. About an hour after liftoff, Virgin Galactic tweeted that VSS Unity separated cleanly from the larger plane and that its two pilots later propelled the spaceship upward by igniting its rocket motor for a “planned partial duration burn.”

During the spaceship’s flight, it reached supersonic speeds of about Mach 1.6, according to a tweet from Virgin Galactic’s founder, British billionaire Richard Branson.

The spaceship landed around 9:15 a.m. Minutes later, Branson tweeted that the company was “back on track.”

“Space feels tantalizingly close now,” he added.
Cheers.
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