Earthshine is one of the most spectacular sights in our night sky. Yet, this astronomical phenomenon is slowly vanishing, and this is providing us with a new warning sign for the climate.
Gaze up at a thin Crescent Moon as it hangs above the horizon, and you will often be able to dimly make out the features that are immersed in the shadow of the Moon’s dark side. This phenomenon is known as Earthshine.
Sunlight reflected from Earth shines upon the Moon’s dark side, in a phenomenon called Earthshine. Credit: Science@NASA
Earthshine results from Earth’s albedo. Of all the incoming sunlight that reaches Earth, roughly one-third gets directly reflected back into space by bright cloud tops and icy surfaces.
Some of this reflected sunlight shines onto the Moon’s surface. This effect is best seen just before and just after a New Moon. That’s when the greatest amount of dark lunar surface is lit by the greatest amount of reflected light from Earth. Anyone looking up at the Moon on those nights will be able to pick out the most prominent features of the lunar surface, even though they are not lit by the direct light of the Sun.
Viewing the Moon from Earth and Earth from the Moon during any month reveals how their phases are complementary. As shown in this image, anyone standing on the lunar surface during a thin Crescent Moon would see a brightly lit “nearly full” Earth. Credit: NASA
However, according to a new study, this phenomenon is slowly disappearing.
Researchers gathered two decades worth of observations of Earthshine, from 1998 to 2017, taken at the Big Bear Solar Observatory, in San Bernardino National Forest, east of Los Angeles, California. The data they collected revealed that Earthshine had dimmed over that time, by about 0.5 per cent. Since the dimming they observed did not match up with changes in the Sun’s brightness during that same time period, that means the dimming is being caused by Earth.
In other words, Earth’s albedo is decreasing, thus the planet is now reflecting less sunlight back into space than it was 20 years ago.
“The albedo drop was such a surprise to us when we analyzed the last three years of data after 17 years of nearly flat albedo,” Philip Goode, the lead researcher on the study from the New Jersey Institute of Technology, said in a press release from the American Geophysical Union (AGU).
This graph shows two decades worth of Earthshine data (black points), alongside data from NASA’s Clouds and the Earth’s Radiant Energy System (CERES) instruments in orbit (blue points). Both reveal that Earth’s albedo is decreasing. CERES detected a significant drop in albedo in 2019. Credit: Goode et al. (2021), Geophysical Research Letters.
While the slow disappearance of Earthshine would be terrible for stargazers, there is a much more significant and troubling impact from this discovery.
Over the years, one of the uncertainties in Earth’s climate system has been whether rising ocean temperatures would increase or decrease cloud cover.
If it increased cloud cover, it could create a self-limiting effect on climate change. Greater cloud cover would increase the amount of sunlight being reflected back into space. As a result, with less sunlight reaching the surface, it would reduce the amount of heat being added to the climate system.
On the other hand, if warming oceans resulted in less cloud cover, it would lower the planet’s albedo. More sunlight would reach the ground, which would result in more heat being added to the climate system. Over time, this would increase the rate of global warming and make the impacts of climate change worse.
Photographed from the International Space Station on July 31, 2011, this image shows the Crescent Moon shining above the limb of Earth, along with the different layers of the atmosphere (troposphere in orange, stratosphere in blue, fading into the mesosphere). The dark side of the Moon is dimly illuminated by the phenomenon of Earthshine. Credit: NASA
This new study found that, along with the detected decrease in Earthshine from their observations, NASA’s Clouds and the Earth’s Radiant Energy System (CERES) project also saw a reduction in the amount of cloud cover over the eastern Pacific Ocean. The CERES instruments, carried by NASA’s Terra and Aqua satellites, found fewer bright, low-lying clouds over a region of the Pacific Ocean off the west coasts of North and South America.
This reduction in clouds is over a region of the ocean where previous studies have shown sea surface temperatures to be on the rise. The increase in temperatures is likely due to changes in a large-scale climate pattern known as the Pacific Decadal Oscillation (PDO).
Thus, based on the findings of this study, it would appear that warmer oceans are reducing the amount of cloud cover, which is very bad news.
Also, although the drop in albedo is only 0.5 per cent, the amount of extra heat it adds to our climate system is nearly the same as what human activity added over the same time period.
“The two-decade decrease in earthshine-derived albedo corresponds to an increase in radiative forcing of about 0.5 Watts per square metre, which is climatologically significant,” the researchers wrote. “For comparison, total anthropogenic forcing increased by about 0.6 Watts per square metre over the same period.”
Green activist hid in Louvre loos before gatecrashing Louis Vuitton’s show
Marie Cohuet hid in a lavatory inside the Louvre art museum for over two hours, plotting her gatecrashing of Louis Vuitton fashion show in protest at the environmental damage that activists say is caused by the fashion industry.
After edging closer to the show’s entrance as the event neared, Cohuet saw her chance when staff were distracted by the glitzy arrival of actress Catherine Deneuve.
Talking animatedly into her phone, Cohuet pretended to be from the organising team and walked in.
She bided her time until the catwalk parade began to a soundtrack of thunderous organ music and church bells, at which point she unfurled her banner and joined the procession of models under a chandelier-lit runway.
“It was a little bit like taking back power,” the 26-year-old environmental campaigner, a member of the Amis de la Terre (Friends of the Earth) group, told Reuters of the seconds before she was bundled to the floor by Louis Vuitton’s security agents.
Her banner was scrawled with the slogan “overconsumption = extinction”.
Cohuet said she had taken a stand on Oct. 5 against a fashion industry that fell short on its promises to act against climate change and pushed brands to renew collections faster, and produce more for less cost.
She accused LVMH of having pledged to reduce its greenhouse gas emissions but excluding its sub-contractors from its calculations.
Asked by Reuters to comment, LVMH said its 2030 target to reduce greenhouse gas emissions by more than half, announced in April, included those of subcontractors.
Critics say that fast fashion, which replicates catwalk trends and high-fashion designs at breakneck speed, is wasteful, exploits low-paid workers and pollutes the environment, including through intensive use of pesticides to grow cotton.
On the runway, Cohuet’s heart was in her stomach as she stared ahead and passed the gazes of cinema stars, LVMH chief executive Bernard Arnault and members of his clan.
“Sometimes an act of civil disobedience is needed, sometimes we need to challenge head-on those who are screwing the planet today, those who are trampling on human rights and social rights,” Cohuet said.
As a teenager at home, she expressed her indignation at the failure of global leaders to act on climate change. It had only been in the past few years that she joined protests, organised petitions and lobbied lawmakers.
Cohuet said she avoided frivolous clothing purchases and air travel but that there was only so much impact an individual could make. Real change must come from governments and leaders of big business, she continued.
Even so, Cohuet holds little hope for meaningful progress at this month’s United Nations COP26 climate change conference summit in Glasgow, Scotland.
“Nice promises get made on paper but then things tend to falter and states fail to turn them into concrete actions,” she said.
(Additional reporting by Mimosa Spencer; writing by Richard Lough; editing by Mark Heinricjh)
Chinese institutions to receive 2nd batch of lunar samples for research – ecns
China has announced a list of research institutions that are to receive the second batch of lunar samples brought back by its Chang’e-5 mission.
The newly distributed samples, weighing about 17.9 grams, will be divided into 51 lots and handed over to scientists from 17 research institutions, according to a notice issued by the State Administration of Science, Technology and Industry for National Defense.
Sixteen institutions that are eligible to study the second batch of lunar samples are from the mainland, including Peking University, Tsinghua University and the Chinese Academy of Sciences. Macau University of Science and Technology is also qualified for using the lunar sample.
According to the notice, the China National Space Administration established a selection commission for the distribution of the samples earlier this month.
The Chang’e-5 probe returned to Earth on Dec. 17, 2020, having retrieved a total of 1,731 grams of lunar samples, mainly rocks and soil from the moon’s surface.
China delivered the first batch of the lunar samples, weighing about 17 grams, to 13 institutions in July.
SpaceX's SN20 Starship prototype completes its first static fire test – Yahoo Movies Canada
SpaceX has taken a major step towards sending the Starship to orbit. On Thursday night, the private space corporation has conducted the SN20 Starship prototype’s first static fire test as part of its preparation for the spacecraft’s launch. According to Space, the SN20 is currently outfitted with two Raptor engines: A standard “sea-level” Raptor and a vacuum version designed to operate in space. At 8:16PM Eastern time on Thursday, the company fired the latter. SpaceX then revealed on Twitter that it was the first ever firing of a Raptor vacuum engine integrated onto a Starship.
Around an hour after that, the SN20 lit up yet again in a second static fire test that may have involved both Raptor engines. The SN20 will eventually have six Raptors — three standard and three vacuum — and will be the first prototype to attempt an orbital launch. A Starship launch system is comprised of the Starship spacecraft itself and a massive first-stage booster called the Super Heavy. Both are designed to be reusable and to carry large payloads for trips to low and higher Earth orbits. It can also eventually be used for longer trips to the Moon and to Mars.
SpaceX doesn’t have a date for the SN20 test flight yet, but the plan is to launch the vehicle with the Super Heavy known as Booster 4 from the company’s Boca Chica site. The booster will splash down in the Gulf of Mexico, while the SN20 will continue its journey towards orbit.
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