Hong Kong, Nov 28 (AP/UNB) — A leader of an international conference on gene editing said Wednesday that the work of a Chinese scientist who claims to have helped make the world's first gene-edited babies showed a failure of self-regulation among scientists.

Nobel laureate David Baltimore said the work of the scientist who made the claim would "be considered irresponsible" because it did not meet criteria many scientists agreed on several years ago before gene editing could be considered.

Baltimore spoke at an international conference in Hong Kong, where the Chinese scientist, He Jiankui (HEH JEE-ahn-qway) of Shenzhen, made his first public comments since his work was revealed.

He said the twin girls were born this month. He said they were conceived to try to help them resist possible future infection with the AIDS virus.

Baltimore said he didn't think that was medically necessary. He said the case showed "there has been a failure of self-regulation by the scientific community" and said the conference committee would meet and issue a statement on Thursday about the future of the field.

Another prominent American scientist speaking at the conference, Harvard Medical School dean Dr. George Daley, warned against a backlash to He's claim. Daley said it would be unfortunate if a misstep with a first case led scientists and regulators to reject the good that could come from altering DNA to treat or prevent diseases.

He has said his lab used the powerful gene-editing tool CRISPR to alter the DNA of human embryos.

There is not yet independent confirmation of his claim, but scientists and regulators have been swift to condemn the experiment as unethical and unscientific.

The National Health Commission has ordered local officials in Guangdong province to investigate He's actions, and his employer, Southern University of Science and Technology, is investigating as well.

The Chinese researcher said he practiced editing mice, monkey and human embryos in the lab for several years and has applied for patents on his methods.

He said he chose embryo gene editing for HIV because these infections are a big problem in China. He sought to disable a gene called CCR5 that forms a protein doorway that allows HIV, the virus that causes AIDS, to enter a cell.

Cape Canaveral, Nov 27 (AP/UNB) —  A NASA spacecraft has landed on Mars to explore the planet's interior.

Flight controllers announced that the spacecraft InSight touched down Monday, after a perilous supersonic descent through the red Martian skies. Confirmation came via radio signals that took more than eight minutes to cross the nearly 100 million miles (160 million kilometers) between Mars and Earth.

There was no immediate word on whether the lander was in good working order. NASA satellites around Mars will provide updates.

It is NASA's eighth successful Mars landing since the 1976 Vikings. The thee-legged, one-armed InSight will operate from the same spot for the next two years. It landed less than 400 miles (600 kilometers) from NASA's Curiosity rover, which until Monday was the youngest working robot in town.

A NASA spacecraft is making a perilous supersonic descent through the atmosphere of Mars, following a six-month journey.

Flight controllers announced that the robotic geologist, InSight, entered the Martian atmosphere Monday afternoon. It should take about six minutes for InSight to get to the surface and land, slowed by a parachute and descent engines.

Updates are coming in via radio signals that take more than eight minutes to cross the nearly 100 million miles (160 million kilometers) between Mars and Earth. The news is being relayed by a pair of mini satellites that have been following InSight since their May launch.

It is NASA's ninth attempt to land at Mars since the 1976 Vikings.

NASA last landed on Mars in 2012 with the Curiosity rover.

A NASA spacecraft is just a few hours away from landing on Mars.

The InSight lander is aiming for a Monday afternoon touchdown on what scientists and engineers hope will be a flat plain.

Everyone involved in the $1 billion international mission is understandably nervous. They say they've had trouble sleeping, and their stomachs are churning.

It's risky business to descend through the Martian atmosphere and land, even for the U.S., the only country to pull it off. It would be NASA's eighth landing on Mars.

A NASA spacecraft's six-month journey to Mars is nearing its dramatic grand finale.

The InSight lander aimed for a touchdown Monday afternoon, as anxiety built among those involved in the $1 billion international effort.

InSight's perilous descent through the Martian atmosphere has stomachs churning and nerves stretched to the max. Although an old pro at this, NASA hasn't attempted a landing at Mars for six years.

The robotic geologist — designed to explore Mars' mysterious insides — must go from 12,300 mph (19,800 kph) to zero in six minutes flat as it pierces the Martian atmosphere, pops out a parachute, fires its descent engines and lands on three legs.

It's aiming for flat red plains, hopefully low on rocks.

Earth's overall success rate at Mars is 40 percent.

Cape Canaveral, Nov 26 (AP/UNB) — With just a day to go, NASA's InSight spacecraft aimed for a bull's-eye touchdown on Mars, zooming in like an arrow with no turning back.

InSight's journey of six months and 300 million miles (482 million kilometers) comes to a precarious grand finale Monday afternoon.

The robotic geologist — designed to explore Mars' insides, surface to core — must go from 12,300 mph (19,800 kph) to zero in six minutes flat as it pierces the Martian atmosphere, pops out a parachute, fires its descent engines and, hopefully, lands on three legs.

It is NASA's first attempt to land on Mars in six years, and all those involved are understandably anxious.

NASA's top science mission official, Thomas Zurbuchen, confided Sunday that his stomach is already churning. The hardest thing is sitting on his hands and doing nothing, he said, except hoping and praying everything goes perfectly for InSight.

"Landing on Mars is one of the hardest single jobs that people have to do in planetary exploration," noted InSight's lead scientist, Bruce Banerdt. "It's such a difficult thing, it's such a dangerous thing that there's always a fairly uncomfortably large chance that something could go wrong."

Earth's success rate at Mars is 40 percent, counting every attempted flyby, orbital flight and landing by the U.S., Russia and other countries dating all the way back to 1960.

But the U.S. has pulled off seven successful Mars landings in the past three decades. With only one failed touchdown, it's an enviable record. No other country has managed to set and operate a spacecraft on the dusty red surface.

InSight could hand NASA its eighth win.

It's shooting for Elysium Planitia, a plain near the Martian equator that the InSight team hopes is as flat as a parking lot in Kansas with few, if any, rocks. This is no rock-collecting expedition. Instead, the stationary 800-pound (360-kilogram) lander will use its 6-foot (1.8-meter) robotic arm to place a mechanical mole and seismometer on the ground.

The self-hammering mole will burrow 16 feet (5 meters) down to measure the planet's internal heat, while the ultra-high-tech seismometer listens for possible marsquakes. Nothing like this has been attempted before at our smaller next-door neighbor, nearly 100 million miles (160 million kilometers) away.

No experiments have ever been moved robotically from the spacecraft to the actual Martian surface. No lander has dug deeper than several inches, and no seismometer has ever worked on Mars.

By examining the deepest, darkest interior of Mars — still preserved from its earliest days — scientists hope to create 3D images that could reveal how our solar system's rocky planets formed 4.5 billion years ago and why they turned out so different. One of the big questions is what made Earth so hospitable to life.

Mars once had flowing rivers and lakes; the deltas and lakebeds are now dry, and the planet cold. Venus is a furnace because of its thick, heat-trapping atmosphere. Mercury, closest to the sun, has a surface that's positively baked.

The planetary know-how gained from InSight's $1 billion, two-year operation could even spill over to rocky worlds beyond our solar system, according to Banerdt. The findings on Mars could help explain the type of conditions at these so-called exoplanets "and how they fit into the story that we're trying to figure out for how planets form," he said.

Concentrating on planetary building blocks, InSight has no life-detecting capability. That will be left for future rovers. NASA's Mars 2020 mission, for instance, will collect rocks for eventual return that could hold evidence of ancient life.

Because it's been so long since NASA's last Martian landfall — the Curiosity rover in 2012 — Mars mania is gripping not only the space and science communities, but everyday folks.

Viewing parties are planned coast to coast at museums, planetariums and libraries, as well as in France, where InSight's seismometer was designed and built. The giant NASDAQ screen in New York's Times Square will start broadcasting NASA Television an hour before InSight's scheduled 3 p.m. EST touchdown; so will the National Air and Space Museum's Udvar-Hazy Center in Chantilly, Virginia, and the Denver Museum of Nature and Science. The InSight spacecraft was built near Denver by Lockheed Martin.

But the real action, at least on Earth, will unfold at NASA's Jet Propulsion Laboratory in Pasadena, California, home to InSight's flight control team. NASA is providing a special 360-degree online broadcast from inside the control center.

Confirmation of touchdown could take minutes — or hours. At the minimum, there's an eight-minute communication lag between Mars and Earth.

A pair of briefcase-size satellites trailing InSight since liftoff in May will try to relay its radio signals to Earth, with a potential lag time of under nine minutes. These experimental CubeSats will fly right past the red planet without stopping. Signals also could travel straight from InSight to radio telescopes in West Virginia and Germany. It will take longer to hear from NASA's Mars orbiters.

Project manager Tom Hoffman said he's trying his best to stay outwardly calm as the hours tick down. Once InSight phones home from the Martian surface, though, he expects to behave much like his three young grandsons did at Thanksgiving dinner, running around like crazy and screaming.

"Just to warn anybody who's sitting near me ... I'm going to unleash my inner 4-year-old on you, so be careful," he said.

Dhaka, Nov 24 (UNB) - Scientists are proposing an ingenious but as-yet-unproven way to tackle climate change: spraying sun-dimming chemicals into the Earth’s atmosphere.

The research by scientists at Harvard and Yale universities, published in the journal Environmental Research Letters, proposes using a technique known as stratospheric aerosol injection, which they say could cut the rate of global warming in half, reports CNN.

The technique would involve spraying large amounts of sulfate particles into the Earth’s lower stratosphere at altitudes as high as 12 miles. The scientists propose delivering the sulfates with specially designed high-altitude aircraft, balloons or large naval-style guns.

Despite the technology being undeveloped and with no existing aircraft suitable for adaptation, the researchers say that “developing a new, purpose-built tanker with substantial payload capabilities would neither be technologically difficult nor prohibitively expensive.”

They estimate the total cost of launching a hypothetical system in 15 years’ time at around $3.5 billion, with running costs of $2.25 billion a year over a 15-year period.

The report does, however, acknowledge that the technique is purely hypothetical.

“We make no judgment about the desirability of SAI,” the report states. “We simply show that a hypothetical deployment program commencing 15 years hence, while both highly uncertain and ambitious, would indeed be technically possible from an engineering perspective. It would also be remarkably inexpensive.”

The researchers also acknowledge potential risks: coordination between multiple countries in both hemispheres would be required, and stratospheric aerosol injection techniques could jeopardize crop yields, lead to droughts or cause extreme weather.

The proposals also don’t address the issue of rising greenhouse gas emissions, which are a leading cause of global warming.

And despite the conviction of the report’s authors, other experts were skeptical.

“From the point of view of climate economics, solar radiation management is still a much worse solution than greenhouse gas emissions: more costly and much more risky over the long run,” said Philippe Thalmann of the École Polytechnique Fédérale de Lausanne, an expert in the economics of climate change.

David Archer of the Department of Geophysical Science at the University of Chicago said, “The problem with engineering climate in this way is that it’s only a temporary Band-Aid covering a problem that will persist essentially forever, actually hundreds of thousands of years for fossil fuel CO2 to finally go away naturally.

“It will be tempting to continue to procrastinate on cleaning up our energy system, but we’d be leaving the planet on a form of life-support. If a future generation failed to pay their climate bill they would get all of our warming all at once.”

Los Angeles, Nov 24 (Xinhua/UNB)-- Scientists have proposed a new way to tackle climate change by spraying sun-dimming chemicals into the Earth's atmosphere, according to a study published Friday.

Scientists at Harvard and Yale universities have proposed using a technique known as Stratospheric Aerosol Injection (SAI), which they believe could cut the rate of global warming by half, according to a paper published in the journal Environmental Research Letters.

The technique would involve spraying large amounts of sulfate particles into the Earth's lower stratosphere at altitudes as high as 12 miles (19.3 km).

However, no existing aircraft design -- even with extensive modifications -- can reasonably fulfill this mission, said the paper.

The scientists propose developing a new purpose-built high-altitude tanker with substantial payload capabilities to deliver the sulfates.

The estimated cost of deploying material is about 2.25 billion U.S. dollars a year over 15 years, according to the paper. Scientists calculate the number of flights at 4,000 for the first year, linearly increasing by 4,000 a year.

The report also acknowledges that the technique is purely hypothetical.

"We make no judgment about the desirability of SAI. We simply show that a hypothetical deployment program commencing 15 years hence, while both highly uncertain and ambitious, would indeed be technically possible from an engineering perspective. It would also be remarkably inexpensive," the paper said.