Thursday, October 24, 2019
Wednesday, October 23, 2019
Mars once had salt lakes similar to those on Earth
October 18, 2019
Texas A&M University
Mars once had salt lakes that
are similar to those on Earth and has gone through wet and dry periods.
Mars once had salt lakes that
are similar to those on Earth and has gone through wet and dry periods,
according to an international team of scientists that includes a Texas A&M
University College of Geosciences researcher.
Marion Nachon, a postdoctoral
research associate in the Department of Geology and Geophysics at Texas
A&M, and colleagues have had their work published in the current issue
of Nature Geoscience.
The team examined Mars'
geological terrains from Gale Crater, an immense 95-mile-wide rocky basin that
is being explored with the NASA Curiosity rover since 2012 as part of the MSL
(Mars Science Laboratory) mission.
The results show that the lake
that was present in Gale Crater over 3 billion years ago underwent a drying
episode, potentially linked to the global drying of Mars.
Gale Crater formed about 3.6
billion years ago when a meteor hit Mars and created its large impact crater.
"Since then, its
geological terrains have recorded the history of Mars, and studies have shown
Gale Crater reveals signs that liquid water was present over its history, which
is a key ingredient of microbial life as we know it," Nachon said.
"During these drying periods, salt ponds eventually formed. It is
difficult to say exactly how large these ponds were, but the lake in Gale
Crater was present for long periods of time -- from at least hundreds of years
to perhaps tens of thousands of years," Nachon said.
So what happened to these salt
lakes?
Nachon said that Mars probably
became dryer over time, and the planet lost its planetary magnetic field, which
left the atmosphere exposed to be stripped by solar wind and radiation over
millions of years.
"With an atmosphere
becoming thinner, the pressure at the surface became lesser, and the conditions
for liquid water to be stable at the surface were not fulfilled anymore,"
Nachon said. "So liquid water became unsustainable and evaporated."
The salt ponds on Mars are
believed to be similar to some found on Earth, especially those in a region
called Altiplano, which is near the Bolivia-Peru border.
Nachon said the Altiplano is
an arid, high-altitude plateau where rivers and streams from mountain ranges
"do not flow to the sea but lead to closed basins, similar to what used to
happen at Gale Crater on Mars," she said. "This hydrology creates
lakes with water levels heavily influenced by climate. During the arid periods
Altiplano lakes become shallow due to evaporation, and some even dry up
entirely. The fact that the Atliplano is mostly vegetation free makes the
region look even more like Mars," she said."
Nachon added that the study
shows that the ancient lake in Gale Crater underwent at least one episode of
drying before "recovering." It's also possible that the lake was
segmented into separate ponds, where some of the ponds could have undergone
more evaporation.
Because up to now only one
location along the rover's path shows such a drying history, Nachon said it
might give clues about how many drying episodes the lake underwent before
Mars's climate became as dry as it is currently.
"It could indicate that
Mars's climate 'dried out' over the long term, on a way that still allowed for
the cyclical presence of a lake," Nachon said. "These results
indicate a past Mars climate that fluctuated between wetter and drier periods.
They also tell us about the types of chemical elements (in this case sulphur, a
key ingredient for life) that were available in the liquid water present at the
surface at the time, and about the type of environmental fluctuations Mars life
would have had to cope with, if it ever existed."
Story Source:
Materials provided by Texas A&M University.
Original written by Keith Randall. Note: Content may be edited for style
and length.
Journal Reference:
W. Rapin, B. L. Ehlmann, G.
Dromart, J. Schieber, N. H. Thomas, W. W. Fischer, V. K. Fox, N. T. Stein, M.
Nachon, B. C. Clark, L. C. Kah, L. Thompson, H. A. Meyer, T. S. J. Gabriel, C.
Hardgrove, N. Mangold, F. Rivera-Hernandez, R. C. Wiens, A. R. Vasavada. An
interval of high salinity in ancient Gale crater lake on Mars. Nature
Geoscience, 2019; DOI: 10.1038/s41561-019-0458-8
Defiant Tarantino won’t re-cut ‘Hollywood’
Film’s suspension comes after
Bruce Lee’s daughter made direct appeal to China’s National Film Administration
DM CHAN
According to a report from the
Hollywood Reporter, US film director Quentin Tarantino will not be re-cutting
his Once Upon a Time in Hollywood for the Chinese mainland, Global
Times reported.
Originally set for release on
Friday, the film was suspended indefinitely a week before its release by
Chinese regulators.
Tarantino, who has final-cut
rights for the film in his contract, refused to cooperate with Chinese
authorities when the film’s co-producer Bona Film Group asked him to help
re-edit the film in order to re-approve the release, according to a report from
film news site Cinema Blend.
The Hollywood Reporter
reported that the suspension came after Bruce Lee’s daughter Shannon Lee made a
direct appeal to China’s National Film Administration to have her father’s
controversial portrayal in the film changed. No official statement about the
suspension has been made by any parties involved.
“I personally do not think
that Shannon Lee, as one of the films’ biggest critics, is the main reason
stopping the film’s release in the Chinese mainland, because according to the
reaction and feedback from those who have seen the film, Tarantino’s use of
Bruce Lee’s image is rather biased and even an insult,” Shi Wenxue, a film
critic and teacher at the Beijing Film Academy, told the Global Times.
The film portrays Bruce Lee as
an arrogant person who claims he could have “crippled” Muhammad Ali in a fight,
yet loses in a fight to Brad Pitt’s Cliff Booth.
“Bruce Lee worked on screen to
change the US stereotype of Chinese. However, after half a century, we see the
expression of such a stereotype, which is unacceptable,” Shi said.
Shannon Lee once told The Wrap
in July that she found the film “disheartening.”
“I understand they want to
make the Brad Pitt character this super bad-ass who could beat up Bruce Lee.
But they didn’t need to treat him in the way that white Hollywood did when he
was alive.”
She added that “It was really
uncomfortable to sit in the theater and listen to people laugh at my father.”
The hashtag related to Shannon
Lee’s dissatisfaction about Once Upon a Time in Hollywood has earned
310 million views on China’s Twitter-like Sina Weibo as of Sunday.
“Bruce Lee’s overconfidence
and arrogant image in the film is a typical stereotype applied to Chinese in
Hollywood movies. Bruce Lee spent his whole life bringing real Chinese
characters to the world, but Tarantino brought this old image into his film
again, which is shameful to us Chinese,” one person commented on Sina Weibo.
According to Shi, Chinese
often play the role of gang members in Chinatown, or arrogant rich
second-generation Chinese in Western film and television. For example, the
Asian characters in the film Crazy Rich Asians catered to the image many US
viewers have when it comes to Asians.
Discrimination is also common
off screen as well. For instance, Vietnamese-American actress Kelly Marie Tran,
who played a role in Star Wars: The Last Jedi, suffered racist attacks and
personal abuse at the hands of Star Wars fans who were dissatisfied with her
character in the film.
EDITORIAL: Don’t Railroad Julian Assange to Virginia
The WikiLeaks legal team
has a strong case to throw out Assange’s extradition request after the
government that wants him extradited got hold of surveillance video of his
privileged attorney-client conversations.
If this were a normal legal
case, WikiLeaks’ lawyers would almost certainly be able to get the
extradition request by the United States for their client Julian Assange thrown
out on the grounds that his privileged conversations with his lawyers at
Ecuador’s London embassy were secretly videotaped.
The very nation that
wants him extradited to stand trial in Virginia has obtained
access to those videos. In a normal extradition case it would be hard
to imagine Britain sending a suspect to a country whose government has already
eavesdropped on that suspect’s defense preparations.
But this is not a normal legal
case.
“The Case should be thrown out
immediately. Not only is it illegal on the face of the treaty, the U.S. has
conducted illegal operations against Assange and his lawyers which are the
subject of a major investigation in Spain,” WikiLeaks Editor-In-Chief
Kristinn Hrafnsson said on Monday as the imprisoned Assange appeared before
a judge in magistrate’s court in London.
“I don’t understand how this
is equitable,” Assange told the court. “This superpower had 10 years to prepare
for this case and I can’t access my writings. It’s very difficult where I am to
do anything but these people have unlimited resources…They are saying
journalists and whistleblowers are enemies of the people. They have unfair
advantages dealing with documents. They [know] the interior of my life with my
psychologist” as the CIA presumably obtained videos of those conversations as
well. Assange was then packed off in a van back to his dreary cell at
Belmarsh prison.
This is a travesty of justice
on many levels.
The existence of Section E of
the 1917 Espionage Act, which technically incriminates the unauthorized
possession and dissemination of U.S. classified material by anyone,
anywhere in the world, effectively criminalizes investigative journalism
and is a travesty that must be challenged on First Amendment grounds.
And now a defendant’s rights
to a fair trial here in Virginia have been seriously undermined, indeed
practically nullified, after his conversations with his attorneys came into the
possession of the government that wants to prosecute him.
But this is not about justice.
This is about revenge.
No case better illustrates
just how corruptly powerful the U.S. and British intelligence services and
militaries have become, as well as the justice system of both nations, which
defend those corrupt interests.
No case better illustrates how
those powerful interests are protected by the legal system in punishing the man
who did most to expose their crimes to a public, a public rendered apathetic by
an Establishment media that has distracted them and presented Assange as an
enemy of the people.
No case better illustrates how
the U.S. and Britain, together carrying out illegal mass surveillance and
unending war, are clinging to a mere pretense of democracy.
That pretense is being
imperiled by the adjudication of this case.
If both governments care in
the very least about maintaining an appearance of following the rule of
law, it has this opportunity: Let Julian Assange go.
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