Connect with us

Science

China’s Chang’e-4 detects hazardous radiation levels on the Moon

Published

 on

Space radiation on the moon is two to three times higher than that on the International Space Station (ISS). This could be one of the biggest dangers for future moon explorers, the Chinese moon probe discovered.

A Chinese-German team reported on the radiation data collected by the moon lander – named Chang’e-4 for the Chinese moon goddess – in the U.S. journal Science Advances. Chang’e-4 made the first ever soft-landing on the far side of the Moon in January, 2019.

The discovery provides the first full measurements of radiation exposure from the lunar surface, vital information for NASA and others aiming to send astronauts to the moon, the study noted.

“This is an immense achievement in the sense that now we have a data set which we can use to benchmark our radiation” and better understand the potential risk to people on the moon, said Thomas Berger, a physicist with the German Space Agency’s medicine institute.

Though Apollo missions in the 1960s and 1970s proved it was safe for people to spend a few days on the lunar surface, NASA did not take daily radiation measurements that would help scientists quantify just how long crews could stay.

Astronauts would get 200 to 1,000 times more radiation on the moon than what we experience on Earth – or five to 10 times more than passengers on a trans-Atlantic airline flight, noted Robert Wimmer-Schweingruber of Christian-Albrechts University in Kiel, Germany.

“The radiation levels we measured on the Moon are about 200 times higher than on the surface of the Earth and five to 10 times higher than on a flight from New York to Frankfurt,” added Wimmer-Schweingruber.

That means humans can stay at most two months on the surface of the Moon without special protection measures, according to Robert Wimmer-Schweingruber, an astrophysicist at the University of Kiel.

Sources of radiation

There are several sources of radiation exposure: galactic cosmic rays, sporadic solar particle events (for example from solar flares), and neutrons and gamma rays from interactions between space radiation and the lunar soil.

Radiation is measured using the unit sievert, which quantifies the amount absorbed by human tissues.

The team found that the radiation exposure on the Moon is 1,369 microsieverts per day – about 2.6 times higher than the International Space Station crew’s daily dose.

The reason for this is that the ISS is still partly shielded by the Earth’s protective magnetic bubble, called the magnetosphere, which deflects most radiation from space.

Earth’s atmosphere provides additional protection for humans on the surface, but we are more exposed the higher up we go.

NASA is planning to bring humans to the Moon by 2024 under the Artemis mission and has said it has plans for a long term presence that would include astronauts working and living on the surface.

For Wimmer-Schweingruber there is one work-around if we want humans to spend more than two or three months: build habitats that are shielded from radiation by coating them with 80 centimeters (30 inches) of lunar soil.

(With input from agencies)

Source:- CGTN

Source link

Continue Reading

Science

City of Vernon extends temporary patio permits for a full year – Vernon News – Castanet.net

Published

 on


The City of Vernon is extending temporary measures so businesses can use outdoor spaces in response to impacts of the COVID-19 pandemic. 

The city created a temporary outdoor commercial use program this past summer, allowing businesses to expand patios into parking lots, sidewalks and parking stalls, so customers and staff could continue practising physical distancing. 

With the extension, businesses can continue using the spaces in the downtown business improvement area until next fall. They will also be able to use single, on-street parking stalls to create pop-up patios or for retail uses during the warmer months, from March 1 to Oct. 31, 2021. 

Businesses with liquor licences will be pre-approved to have licences extended into the temporary spaces.

“Through the temporary outdoor commercial use program, the city is helping our community maintain physical distancing,” Mayor Victor Cumming said in a press release. “This program extension will also help businesses continue to adapt as we head into the colder months and plan ahead for spring and summer.”    

For information on the guidelines, visit vernon.ca/covid-19/.

Let’s block ads! (Why?)



Source link

Continue Reading

Science

NASA spacecraft collects up to 4.5 pounds of asteroid to be sent to Earth – Global News

Published

 on


A NASA spacecraft tucked more than two pounds of asteroid samples into a capsule for return to Earth after losing some of its precious loot because of a jammed lid, scientists said Thursday.

They won’t know the precise amount of the cosmic haul from asteroid Bennu, more than 200 million miles (322 million kilometres) away, until the capsule parachutes into the Utah desert in 2023.

Read more:
Scans reveal failed planet-turned-asteroid worth up to $10,000 quadrillion

“We’ve still got a lot of work to do” to get the samples back safely, said lead scientist Dante Lauretta of the University of Arizona.

The spacecraft Osiris-Rex won’t depart Bennu’s neighbourhood until March at the earliest, when the asteroid and Earth are properly aligned.

Story continues below advertisement

Osiris-Rex collected so much material from Bennu’s rough surface on Oct. 20 that rocks got wedged in the rim of the container and jammed it open. Some of the samples were seen escaping into space, so flight controllers moved up the crucial stowing operation.






2:08
NASA spacecraft gets sample from nearby asteroid Bennu


NASA spacecraft gets sample from nearby asteroid Bennu

Based on images, scientists believe Osiris-Rex grabbed 4 1/2 pounds (2 kilograms) of rubble, a full load. The minimum requirement had been 2 ounces (60 grams) — a handful or two.

“Just imagine a sack of flour at the grocery store,” Lauretta said of the initial haul.

But tens of grams of material were lost following the successful touch-and-go maneuver and again this week when the spacecraft’s robot arm moved to put the samples inside the capsule.

Read more:
NASA identifies ‘asteroid’ expected to become mini-moon next month as old rocket

Story continues below advertisement

“Even though my heart breaks for the loss of sample, it turned out to be a pretty cool science experiment and we’re learning a lot,” Lauretta told reporters.

While collecting the samples, the container on the end of the robot arm pressed down nine to 19 inches (24 to 48 centimetres) during the six seconds of contact, indicating a sandy and flaky interior beneath the rough surface, Lauretta said.

The slow, tedious stowing operation took 36 hours. After each successful step, flight controllers cheered, saving the biggest and loudest response when the lid on the capsule finally was closed and latched, sealing the samples inside.


Click to play video 'Space Talk: Asteroid mining'



6:06
Space Talk: Asteroid mining


Space Talk: Asteroid mining

It will be September 2023 — seven years after Osiris-Rex rocketed from Cape Canaveral — before the samples arrive here.

Rich in carbon, the solar-orbiting Bennu is believed to hold the preserved building blocks of the solar system. Scientists said the remnants can help explain how our solar system’s planets formed billions of years ago and how life on Earth came to be. The samples also can help improve our odds, they said, if a doomsday rock heads our way.

Story continues below advertisement

Bennu — a black, roundish rock bigger than New York’s Empire State Building — could come dangerously close to Earth late in the next decade. The odds of a strike are 1-in-2,700. The good news is that while packing a punch, it won’t wipe out the home planet.

Japan, meanwhile, has retrieved samples from other asteroids twice in the past two decades, although just tiny amounts. The second batch is due to arrive in December.

© 2020 The Canadian Press

Let’s block ads! (Why?)



Source link

Continue Reading

Science

Man and dog: Ancient genetics study reveals complex history – FRANCE 24

Published

 on


Issued on: 29/10/2020 – 19:30Modified: 29/10/2020 – 19:28

Advertising

Washington (AFP)

Much of the diversity seen in modern dog populations was already present around the time the last Ice Age had ended 11,000 years ago, a global study of ancient DNA revealed Thursday.

The paper, published in Science, showed how our canine companions spread across the world with their masters, but also found intriguing periods when our shared history was decoupled.

A research team led by the Francis Crick Institute sequenced the genomes of 27 dogs, some of which lived nearly 11,000 years ago, across Europe, the Near East and Siberia.

They found that by this time, well before the domestication of any other animal, there were already at least five different types of dog with distinct genetic ancestries.

Pontus Skoglund of Crick’s Ancient Genomics laboratory, the paper’s senior author, said: “Some of the variation you see between dogs walking down the street today originated in the Ice Age.

“By the end of this period, dogs were already widespread across the northern hemisphere.”

He added this implied that the diversity arose far earlier, “way back in time, during the hunter gatherer Stone Age, the Paleolithic, way before agriculture.”

When and where dogs first diverged from wolves is a contentious matter — analyses of genetic data indicates a window of roughly 25,000-40,000 years ago.

The new paper doesn’t enter this vexed debate but does support the idea that, unlike other animals such as pigs which appear to have been domesticated in multiple locations over time, there is a “single origin” from wolves to dogs.

The scientists found that all dogs probably share a common ancestry “from a single ancient, now-extinct wolf population,” with limited gene flow from wolves since domestication but substantial dog-to-wolf gene flow.

– Convergent evolution –

By extracting and analyzing ancient DNA from skeletal material, the researchers were able to see evolutionary changes as they occurred thousands of years ago.

For instance, European dogs around four or five thousand years ago were highly diverse and appeared to originate from highly distinct populations from Near Eastern and Siberian dogs. But over time, this diversity was lost.

“Although the European dogs we see today come in such an extraordinary array of shapes and forms, genetically they derive from only a very narrow subset of the diversity that used to exist,” said the paper’s lead author Anders Bergstrom.

Evolutionary pathways between our two species have at times followed similar routes.

Humans, for example, have more copies than chimpanzees of a gene that creates a digestive enzyme called salivary amylase, which helps us break down high-starch diets.

Likewise, the paper demonstrated that early dogs carried extra copies of these genes compared to wolves, and this trend only increased over time as their diets adapted to agricultural life.

This builds on previous research that found Arctic sled dogs, like Inuits, have evolved similar metabolic pathways to allow them to process high-fat diets.

There have also been periods when our histories have not run in parallel — for example the loss of diversity that once existed in dogs in early Europe was caused by the spread of single invasive species, an event not mirrored in human migrations.

The field of ancient DNA study has revolutionized the study of our ancestors and researchers are hopeful it can do the same for dogs, our longest animal allies.

“Understanding the history of dogs teaches us not just about their history but also about our own history,” said Bergstrom.

Let’s block ads! (Why?)



Source link

Continue Reading

Trending