Science & TechnologyS


Chalkboard

String Theory: A dream and a nightmare

Ethan Siegel
Forbes
Mon, 23 Mar 2020 16:02 UTC
string theory
© University of CambridgeThe string landscape might be a fascinating idea that's full of theoretical potential, but it cannot explain why the value of such a finely-tuned parameter like the cosmological constant, the initial expansion rate, or the total energy density have the values that they do. Still, understanding why this value takes on the particular one it does is a fine-tuning question that most scientists assume has a physically-motivated answer.
String theory is perhaps the most controversial big idea in all of science today. On the one hand, it's a mathematically compelling framework that offers the potential to unify the Standard Model with General Relativity, providing a quantum description of gravity and providing deep insights into how we conceive of the entire Universe. On the other hand, its predictions are all over the map, untestable in practice, and require an enormous set of assumptions that are unsupported by an iota of scientific evidence.

For perhaps the last 35 years, string theory has been the dominant idea in theoretical particle physics, with more scientific papers arising from it than any other idea. And yet it has not produced even one testable prediction in all that time, leading many to decry that it hasn't even risen to the standard of science. String theory is simultaneously one of the best ideas in the entire history of theoretical physics and one of our greatest disappointments. Here's why.
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Blue Planet

Fragment of lost continent discovered off coast of Canada

Peter Dockrill
Science Alert
Mon, 23 Mar 2020 12:00 UTC
Baffin Island
© (Jennifer Latuperisa-Andresen/Unsplash)Baffin Island.
Scientists have uncovered a splintered remnant of Earth's continental crust from millions of years ago, embedded in the isolated wilderness of northern Canada.

Baffin Island, located in between the Canadian mainland and Greenland, is a vast Arctic expanse covering over 500,000 square kilometres (almost 200,000 square miles), making it the fifth largest island in the world.

While the island comprises part of the newest recognised territory in Canada - Nunavut, formally established in 1999 - a new discovery shows this ancient landmass has undisclosed ties that stretch backwards in time so far, they actually emanate from a distant geologic eon.

While analysing igneous rock samples recovered from diamond exploration drilling in the Chidliak Kimberlite Province at the southern stretches of Baffin Island, researchers identified a mineral signature in the rock they had never expected to find.

Comment: See also:

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Bizarro Earth

Russia to create first ever 3D Moon map to help decide where cosmonauts will land


RT
Sun, 22 Mar 2020 00:00 UTC
Moon 3D Map
© Roscosmos
Russia is creating the first ever topographic three dimensional map of the Moon to help decide where cosmonauts will land in future journeys to Earth's natural satellite.

The director of the Russian Space Research Institute Anatoly Petrukovich announced the plan on Sunday, saying the map will be created using stereo imaging and it will have a resolution of two to three meters.

"After the work of the American satellites, we have planar maps of the Lunar surface, but here, using stereo processing and light analysis, we will get a universal altitudes map of the entire Moon with high accuracy," he said.

Comment: See also:

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Solar Flares

Explosion on the far side of the sun


Space Weather
Sun, 22 Mar 2020 03:41 UTC
CME farside of sun
© YouTube/nemesis maturity (screen capture)
Solar Minimum is not as quiet as you think. On March 20th, something exploded on the farside of the sun. The Solar and Heliospheric Observatory (SOHO) saw the debris flying over the sun's eastern limb:


Comment: Preparing for the inevitable solar storm

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Moon

China's Chang'e 4 lander and Yutu 2 rover reawaken on far side of the moon

Andrew Jones
Space.com
Sat, 21 Mar 2020 17:15 UTC
china lunar rover Chang'e 4
© BACC/Our SpaceThe green line shows Yutu 2's route from the landing site. The yellow illustrates the new drive plan.
China's Chang'e 4 mission has started its 16th lunar day of work on the far side of the moon, with the Yutu 2 rover beginning a journey in search of new areas.

Both the Chang'e 4 lander and the Yutu 2 rover and their science payloads are in good operating condition, despite the spacecraft spending over a year in the harsh conditions on the lunar surface.

Yutu 2 awoke on March 17 following sunrise over its position in Von Kármán Crater, with the lander following 16 hours later on Mar. 18, according to the China Lunar Exploration Program (CLEP).

The lander will continue its low-frequency radio astronomy observations, but a new plan has been formulated for the Yutu 2 rover, which has already provided insights into the composition of the surface and what lies below.

Watch video here.
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Beaker

The elusive 'ideal glass' would explain why glass exists at all

Natalie Wolchover
Quanta Magazine
Wed, 11 Mar 2020 15:20 UTC
fossilized amber glass shard
© James Rajotte for Quanta MagazineMiguel Ramos holds up a piece of fossilized amber. After settling for 110 million years, the amber was thought to approach the state of ideal glass, where molecules are packed together in the densest possible random arrangement.
Glass is anything that's rigid like a crystal, yet made of disordered molecules like a liquid. To understand why it exists, researchers are attempting to create the perfect, still-hypothetical "ideal glass."

In 2008, Miguel Ramos read in the newspaper that 110-million-year-old amber bearing pristine Mesozoic insects had been discovered a few hours' drive from Madrid, where he lived. A physicist who specializes in glass, Ramos had wanted for years to get his hands on ancient amber. He contacted the paleontologists working at the site, who invited him to visit.

"They provided me with the clear samples that are not good for them," he said. "They have no interesting insects or whatever ... but they are perfect for me."

Ramos spent the next several years intermittently working on measurements of the ancient glass. He hoped that the fossilized tree resin, after aging for so long, might approach a hypothetical form of matter known as ideal glass.
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Mars

Scientists unravel mystery behind billions of tons of ice on hellishly hot Mercury


Sputnik
Sat, 21 Mar 2020 10:35 UTC
mercury surface
Like the Moon, some parts of Mercury are covered with craters where temperatures reach cold extremes. But the Earth's satellite has tiny amounts of ice, whereas on Mercury there is plenty of it. This mystery has made scientists wonder whether Mercury has received water in a way that couldn't work on the Moon. But if so - how?

Temperatures on Mercury can reach 400 degrees Celsius (750 degrees Fahrenheit), yet for some reason the closest planet to the Sun has vast amounts of ice. A new study conducted by researchers from the Georgia Institute of Technology seems to have cracked this mystery thanks to chemistry.

Solar winds that hit Mercury carry charged particles, including protons. Interacting with the planet's minerals, they generate so-called hydroxyl groups, which under extreme heat free up and smash into each other, producing water molecules and hydrogen. These molecules travel around the planet and some of them land in craters in permanently shadowed regions, areas, which never receive direct sunlight and have extremely cold temperatures.
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Christmas Tree

Secrets of '1,000-year-old trees' unlocked

Helen Briggs
BBC News
Mon, 13 Jan 2020 00:00 UTC
Ginko tree
© GETTY IMAGESGinkgo leaves in autumn
Scientists have discovered the secret of how the ginkgo tree can live for more than 1,000 years.

A study found the tree makes protective chemicals that fend off diseases and drought.

And, unlike many other plants, its genes are not programmed to trigger inexorable decline when its youth is over.

The ginkgo can be found in parks and gardens across the world, but is on the brink of extinction in the wild.

"The secret is maintaining a really healthy defence system and being a species that does not have a pre-determined senescence (ageing) programme," said Richard Dixon of the University of North Texas, Denton.
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Rocket

Pentagon: Successful flight test of hypersonic glide body

Jen Judson
Defense News
Fri, 20 Mar 2020 00:00 UTC
Hypersonic testing
© U.S. Defense DepartmentThe U.S. Defense Department tested a hypersonic glide body in a flight experiment conducted from the Pacific Missile Range Facility in Kauai, Hawaii, on March 19, 2020.
The Pentagon made good on its word that it would test a hypersonic glide body in a flight test this year, launching it from the Pacific Missile Range Facility in Kauai, Hawaii, on March 19 at 10:30 p.m. local time. The test was deemed a success.

The Common-Hypersonic Glide Body, or C-HGB, launched and flew at hypersonic speed to "a designated impact point," according to a statement issued March 20 by the Department of Defense. The test was a joint effort between the Navy and Army.

Hypersonic weapons are capable of flying faster than the speed of sound — Mach 5 — and can maneuver between varying altitudes and azimuths, making it harder to detect.

The DoD has been jointly developing the C-HGB that will serve as the base of its offensive hypersonic missile. The test marks a major step forward in accomplishing that mission amid mounting criticism that the United States is behind China and Russia in hypersonic weapons development.

The C-HGB will be made up of the weapon's warhead, guidance system, cabling and thermal protection shield. Each service will use the C-HGB as the base while developing individual weapon systems such as launchers capable of firing the weapons from land or sea.
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Attention

One of Darwin's theories is FINALLY proved (but not really)


Uncommon Descent
Thu, 19 Mar 2020 07:45 UTC
evolution decline
A friend wrote to say that this headline is "a complete head-scratcher":
One of Darwin's evolution theories finally proved

Scientists have proved one of Charles Darwin's theories of evolution for the first time — nearly 140 years after his death. Researchers discovered mammal subspecies play a more important role in evolution than previously thought. Her research could now be used to predict which species conservationists should focus on protecting. - St John's College, University of Cambridge
Huh? We had been given to understand that Darwin's theories were as dead certain as math. Jonathan Wells, who has a beagle's nose for Darwin hype, offers some thoughts on this example:

Comment: See also:

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