Posts Tagged ‘space’

By Rob Picheta

Aliens definitely exist, Britain’s first astronaut has said — and it’s possible they’re living among us on Earth but have gone undetected so far.

Helen Sharman, who visited the Soviet Mir space station in 1991, told the Observer newspaper on Sunday that “aliens exist, there’s no two ways about it.”

“There are so many billions of stars out there in the universe that there must be all sorts of different forms of life,” she went on. “Will they be like you and me, made up of carbon and nitrogen? Maybe not.”

Then, in a tantalizing theory that should probably make you very suspicious of your colleagues, Sharman added: “It’s possible they’re here right now and we simply can’t see them.”
Sharman was the first of seven Britons to enter space.

The chemist spent eight days as a researcher on the space mission when she was 27, making her one of the youngest people to enter orbit.

NASA rovers are trawling Mars for evidence of past or present life forms, but humankind’s endless fascination with extraterrestrial life forms has so far proved fruitless.

Sharman is not the only person to speculate that we’ve had brushes with aliens, though.

A former Pentagon official who led a secret government program to research potential UFOs, revealed in 2017, told CNN at the time that he believes there is evidence of alien life reaching Earth.

Elsewhere in her interview, Sharman said there is “no greater beauty than looking at the Earth from up high.”

“I’ll never forget the first time I saw it,” she added.

Sharman also discussed her frustration with observers defining her by her sex. “People often describe me as the first British woman in space, but I was actually the first British person. It’s telling that we would otherwise assume it was a man,” she said.

“When Tim Peake went into space, some people simply forgot about me. A man going first would be the norm, so I’m thrilled that I got to upset that order.”

https://www.cnn.com/2020/01/06/uk/helen-sharman-aliens-exist-scli-scn-gbr-intl/index.html

by Steve Nadis

In January 1916, Karl Schwarzschild, a German physicist who was stationed as a soldier on the eastern front, produced the first exact solution to the equations of general relativity, Albert Einstein’s radical, two-month-old theory of gravity. General relativity portrayed gravity not as an attractive force, as it had long been understood, but rather as the effect of curved space and time. Schwarzschild’s solution revealed the curvature of space-time around a stationary ball of matter.

Curiously, Schwarzschild noticed that if this matter were confined within a small enough radius, there would be a point of infinite curvature and density — a “singularity” — at the center.

Infinities cropping up in physics are usually cause for alarm, and neither Einstein, upon learning of the soldier’s result, nor Schwarzschild himself believed that such objects really exist. But starting in the 1970s, evidence mounted that the universe contains droves of these entities — dubbed “black holes” because their gravity is so strong that nothing going into them, not even light, can come out. The nature of the singularities inside black holes has been a mystery ever since.

Recently, a team of researchers affiliated with Harvard University’s Black Hole Initiative (BHI) made significant progress on this puzzle. Paul Chesler, Ramesh Narayan and Erik Curiel probed the interiors of theoretical black holes that resemble those studied by astronomers, seeking to determine what kind of singularity is found inside. A singularity is not a place where quantities really become infinite, but “a place where general relativity breaks down,” Chesler explained. At such a point, general relativity is thought to give way to a more exact, as yet unknown, quantum-scale description of gravity. But there are three different ways in which Einstein’s theory can go haywire, leading to three different kinds of possible singularities. “Knowing when and where general relativity breaks down is useful in knowing what theory [of quantum gravity] lies beyond it,” Chesler said.

The BHI group built on a major advance achieved in 1963, when the mathematician Roy Kerr solved Einstein’s equations for a spinning black hole — a more realistic situation than the one Schwarzschild took on since practically everything in the universe rotates. This problem was harder than Schwarzschild’s, because rotating objects have bulges in the center and therefore lack spherical symmetry. Kerr’s solution unambiguously described the region outside a spinning black hole, but not its interior.

Kerr’s black hole was still somewhat unrealistic, as it occupied a space devoid of matter. This, the BHI researchers realized, had the effect of making the solution unstable; the addition of even a single particle could drastically change the black hole’s interior space-time geometry. In an attempt to make their model more realistic and more stable, they sprinkled matter of a special kind called an “elementary scalar field” in and around their theoretical black hole. And whereas the original Kerr solution concerned an “eternal” black hole that has always been there, the black holes in their analysis formed from gravitational collapse, like the ones that abound in the cosmos.

First, Chesler, Narayan and Curiel tested their methodology on a charged, non-spinning, spherical black hole formed from the gravitational collapse of matter in an elementary scalar field. They detailed their findings in a paper posted on the scientific preprint site arxiv.org in February. Next, Chesler tackled the more complicated equations pertaining to a similarly formed rotating black hole, reporting his solo results three months later.

Their analyses showed that both types of black holes contain two distinct kinds of singularities. A black hole is encased within a sphere called an event horizon: Once matter or light crosses this invisible boundary and enters the black hole, it cannot escape. Inside the event horizon, charged stationary and rotating black holes are known to have a second spherical surface of no return, called the inner horizon. Chesler and his colleagues found that for the black holes they studied, a “null” singularity inevitably forms at the inner horizon, a finding consistent with prior results. Matter and radiation can pass through this kind of singularity for most of the black hole’s lifetime, Chesler explained, but as time goes on the space-time curvature grows exponentially, “becoming infinite at infinitely late times.”

The physicists most wanted to find out whether their quasi-realistic black holes have a central singularity — a fact that had only been established for certain for simple Schwarzschild black holes. And if there is a central singularity, they wanted to determine whether it is “spacelike” or “timelike.” These terms derive from the fact that once a particle approaches a spacelike singularity, it is not possible to evolve the equations of general relativity forward in time; evolution is only allowed along the space direction. Conversely, a particle approaching a timelike singularity will not inexorably be drawn inside; it still has a possible future and can therefore move forward in time, although its position in space is fixed. Outside observers cannot see spacelike singularities because light waves always move into them and never come out. Light waves can come out of timelike singularities, however, making them visible to outsiders.

Of these two types, a spacelike singularity may be preferable to physicists because general relativity only breaks down at the point of singularity itself. For a timelike singularity, the theory falters everywhere around that point. A physicist has no way of predicting, for instance, whether radiation will emerge from a timelike singularity and what its intensity or amplitude might be.

The group found that for both types of black holes they examined, there is indeed a central singularity, and it is always spacelike. That was assumed to be the case by many, if not most, astrophysicists who held an opinion, Chesler noted, “but it was not known for certain.”

The physicist Amos Ori, a black hole expert at the Technion in Haifa, Israel, said of Chesler’s new paper, “To the best of my knowledge, this is the first time that such a direct derivation has been given for the occurrence of a spacelike singularity inside spinning black holes.”

Gaurav Khanna, a physicist at the University of Massachusetts, Dartmouth, who also investigates black hole singularities, called the BHI team’s studies “great progress — a quantum leap beyond previous efforts in this area.”

While Chesler and his collaborators have strengthened the case that astrophysical black holes have spacelike singularities at their cores, they haven’t proved it yet. Their next step is to make more realistic calculations that go beyond elementary scalar fields and incorporate messier forms of matter and radiation.

Chesler stressed that the singularities that appear in black hole calculations should disappear when physicists craft a quantum theory of gravity that can handle the extreme conditions found at those points. According to Chesler, the act of pushing Einstein’s theory to its limits and seeing exactly how it fails “can guide you in constructing the next theory.”

https://www.quantamagazine.org/black-hole-singularities-are-as-inescapable-as-expected-20191202/?utm_source=Nature+Briefing&utm_campaign=6cddda34dd-briefing-dy-20191206&utm_medium=email&utm_term=0_c9dfd39373-6cddda34dd-44039353


Ann Hodges (center) poses with her meteorite, underneath the point where it crashed through her house, with Sylacauga, Alabama mayor Ed Howard (left) and the town’s police chief W.D. Ashcraft. Hodges was struck by the meteorite while on her couch on Nov. 30, 1954. She donated it to the University of Alabama’s Museum of Natural History in 1956.

By Chelsea Gohd

Sixty-five years ago, a few days after Thanksgiving, Ann Hodges was snuggled up on the sofa in her Alabama home when a 4.5-billion-year-old meteorite crashed through the ceiling and struck the left side of her body. Not the best interruption to the holiday season.

The cosmic event, which took place on Nov. 30, 1954, was the first known reported instance of a human being struck by a meteorite and suffering an injury. The softball-size space rock, weighing about 8.5 lbs. (3.8 kilograms), burst through the roof of Hodges’ house in Sylacauga at 2:46 p.m. local time, bouncing off a large radio console before striking her and leaving a large, dark bruise.

The meteorite that struck Hodges, who was 31 at the time, turned out to be one-half of a larger rock that split in two as it fell toward Earth. The piece that didn’t hit Hodges landed a few miles away and is now in the collections of the Smithsonian’s National Museum of Natural History. In 2017, a 10.3-gram piece of the space rock that hit Hodges sold at auction for $7,500.

Before it ended up leaving a serious welt on Hodges’ side, people across eastern Alabama say they saw a bright light in the sky. Reports poured in of a reddish light, and some observers even described a fireball that trailed smoke and left an arc of light in the afternoon sky. After Hodges was struck and the meteorite landed, she and her mother, who was home at the time, tried to figure out what had happened.

Dust filled the house after the crash, but as it settled and they spotted the rock and the enormous bruise on Hodges, the two women called the police and fire department.

Now, as a local geologist was called to the scene to verify what the object was, word quickly spread about what happened. However, the event occurred in 1954, and not everyone was convinced that this strange rock was a meteorite. Some thought it could’ve been debris from a plane crash, and some thought it could have even come from what was then the Soviet Union.

Still, despite a few skeptics, people from all over flocked to Hodges’ home to see the woman hit by a space rock, a crowd that Hodges’ husband found as he returned from work that night. “We had a little excitement around here today,” Ann Hodges told the Associated Press. “I haven’t been able to sleep since I was hit,” she said. With all of this commotion around her, Hodges was soon hospitalized, though, despite the massive mark on her side, was not too seriously injured.

“Think of how many people have lived throughout human history,” Michael Reynolds, who wrote the book “Falling Stars: A Guide to Meteors and Meteorites,” said to National Geographic. “You have a better chance of getting hit by a tornado and a bolt of lightning and a hurricane all at the same time.”

Shockingly, Hodges is not the only person to have been hit by a meteorite, but it is still exceptionally rare.

In 2009, a 14-year-old German boy, Gerrit Blank, was hit in the hand by a pea-size meteorite. While he wasn’t seriously injured, the rock did leave a scar and gave the boy quite a fright. “When it hit me it knocked me flying and then was still going fast enough to bury itself into the road,” said Blank.

https://www.space.com/meteorite-hit-alabama-woman-65-years-ago.html?utm_source=notification


Scientists found three bio-essential sugars, including ribosome, in samples from a pair of meteorites. Photo by Yoshihiro Furukawa

By Brooks Hays

For the first time, scientists have identified sugars essential to life inside meteorites.

The discovery, described this week in the journal PNAS, supports the theory that a bombardment of meteorites provided ancient Earth with the building blocks required for the origin of life.

An international team of scientists identified a trio of bio-essential sugars, including ribose, arabinose and xylose, inside two carbon-rich meteorites.

“Ribose is an essential sugar for present life as a building block of RNA, which could have both stored information and catalyzed reactions in primitive life on Earth,” researchers wrote in their new paper.

Scientists have previously found other biomolecules in meteorites, including amino acids, which form proteins, and nucleobases, the building blocks of DNA and RNA. But until now, scientists hadn’t been able to find sugars.

“The research provides the first direct evidence of ribose in space and the delivery of the sugar to Earth,” Yoshihiro Furukawa, researcher at Tohoku University in Japan, said in news release. “The extraterrestrial sugar might have contributed to the formation of RNA on the prebiotic Earth which possibly led to the origin of life.”

To find the sugars, scientists used gas chromatography mass spectrometry to analyze the chemical components of powdered meteorite samples. The method identifies molecules by measuring their mass and electric charge.

The research team used isotopic analysis to confirm the sugar’s interplanetary origins. Their tests showed a higher concentration of carbon 13 in the sugars. Carbon 13 is a heavier carbon isotope that is less abundant in terrestrial samples.

While planetary scientists continue to search for signs of life on other planets, researchers are still trying to figure out how biology — or the first living organisms — emerged from non-biological chemical processes here on Earth.

While some scientists theorize that RNA and DNA evolved together, or emerged simultaneously, others estimate that RNA came first and evolved DNA. RNA can catalyze chemical reactions, as well as make copies of itself, something DNA can’t do. Some research suggests metabolism preceded both RNA and DNA.

The latest discovery supports the theory that RNA was the initial conductor of life’s assembly.

“The sugar in DNA, 2-deoxyribose, was not detected in any of the meteorites analyzed in this study,” said study co-author Danny Glavin, researcher at NASA’s Goddard Space Flight Center. “This is important since there could have been a delivery bias of extraterrestrial ribose to the early Earth which is consistent with the hypothesis that RNA evolved first.”

Scientists hope to gain additional insights into life’s origins as they probe other meteorite samples for evidence of sugar’s abundance.

https://www.upi.com/Science_News/2019/11/19/Sugars-essential-to-life-detected-in-meteorites-a-first/4421574186445/?sl=1

by Morgan McFall-Johnsen

The NASA scientist Jessie Christiansen made a video that traces our solar system’s movement through the Milky Way as dinosaurs emerged, went extinct, and were replaced by mammals on Earth.

Our sun orbits the galaxy’s center, so many dinosaurs roamed the Earth while the planet was on the other side of the Milky Way.

Our solar system’s orbit keeps us just the right distance from the galaxy’s chaotic center for life to exist.

When dinosaurs ruled the Earth, the planet was on a completely different side of the galaxy.

A new animation by the NASA scientist Jessie Christiansen shows just how long the dinosaurs’ reign lasted — and how short the era of humans has been in comparison — by tracing our solar system’s movement through the Milky Way.

Our sun orbits the galaxy’s center, completing its rotation every 250 million years or so. So Christiansen’s animation shows that the last time our solar system was at its current point in the galaxy, the Triassic period was in full swing and dinosaurs were just emerging. Many of the most iconic dinosaurs roamed the Earth when the planet was in a very different part of the Milky Way.

Christiansen got the idea to illustrate this history when she was leading a stargazing party at the California Institute of Technology in Pasadena. Attendees were astonished when she mentioned that our solar system was across the galaxy when dinosaurs roamed.

“That was the first time I realized that those time scales — archaeological, fossil-record time scales and astronomical time scales — actually kind of match along together,” Christiansen told Business Insider. “Then I had this idea that I could map out dinosaur evolution through the galaxy’s rotation.”

Christiansen said it took her about four hours to make the film using timed animations in PowerPoint. She also noted a couple of minor corrections to the text in her video: Plesiosaurs are not dinosaurs, and we complete a galactic orbit every 250 million years, not 200 million years.

‘A spiral through space’

But galactic movement is more complicated than the video shows. The other stars and planetary systems in the galaxy are also moving, at different speeds and in different orbits. The inner portions spin faster than the outer regions.

What’s more, the galaxy itself is moving through space, slowly approaching the nearby Andromeda galaxy.

“The animation kind of makes it seem like we’ve come back to the same spot, but in reality the whole galaxy has moved a very long way,” Christiansen said. “It’s more like we’re doing a spiral through space. As the whole galaxy’s moving and we’re rotating around the center, it kind of creates this spiral.”

So in the solar system’s rotation around the galactic center, we’re not returning to a fixed point. The neighborhood is different from the last time we were here.

Earth, however, is not drastically different; it still supports complex life. That’s partially thanks to the path of our sun’s galactic orbit.

“Our solar system doesn’t travel to the center of the galaxy and then back again,” Christiansen said. “We always stay about this distance away.”

In other words, even as our solar system travels through the Milky Way, it doesn’t approach the inhospitable center, where life probably wouldn’t survive.

“There’s a lot of stars, it’s dynamically unstable, there’s a lot of radiation,” Christiansen said. “Our solar system certainly doesn’t pass through that.”

That’s a huge part of why dinosaurs, mammals, or any other form of life can exist on Earth.

https://www.businessinsider.com/video-nasa-scientist-dinosaurs-milky-way-2019-10


Russian cosmonaut Alexei Leonov, right, and Russian President Vladimir Putin pose for a photo in 2013.

By Scottie Andrew

Alexei Leonov, the first person to perform a spacewalk, died this week. He was 85.

Russian space agency Roscosmos Space Corporation announced his passing Friday. State news agency RIA-Novosti reported he’d been chronically ill before his death.

Though Leonov wasn’t the first man on the moon (a goal he wasn’t shy about), he earned his own “first” in the space race between the US and Soviet Union. On March 18, 1965, he embarked on the first spacewalk, spending 12 minutes outside the Voskhod 2 capsule.

The first American to walk in space, Ed White, wouldn’t do so until June that same year.

On the Apollo-Soyuz mission in 1975, Leonov met with US astronauts in space and gave TV viewers tours of their respective crafts, the first time Soviet and US cosmonauts collaborated in space. The mission is credited with kick-starting eventual international cooperation aboard the International Space Station.

Leonov was also a celebrated artist who brought colored pencils to space to sketch the view of Earth. His drawing of the sunrise is considered the first piece of art created in space.

His funeral will be held October 15 at Mytishchi Military Memorial cemetery outside Moscow.

https://www.cnn.com/2019/10/11/world/alexei-leonov-first-spacewalk-death-scn-trnd/index.html


Tracks made by Yutu-2 while navigating hazards during lunar day 8, which occurred during late July and early August 2019.

By Andrew Jones

China’s Chang’e-4 lunar rover has discovered an unusually colored, ‘gel-like’ substance during its exploration activities on the far side of the moon.

The mission’s rover, Yutu-2, stumbled on that surprise during lunar day 8. The discovery prompted scientists on the mission to postpone other driving plans for the rover, and instead focus its instruments on trying to figure out what the strange material is.

Day 8 started on July 25; Yutu-2 began navigating a path through an area littered with various small impact craters, with the help and planning of drivers at the Beijing Aerospace Control Center, according to a Yutu-2 ‘drive diary’ published on Aug. 17 by the government-sanctioned Chinese-language publication Our Space, which focuses on space and science communication.

On July 28, the Chang’e-4 team was preparing to power Yutu-2 down for its usual midday ‘nap’ to protect the rover from high temperatures and radiation from the sun high in the sky. A team member checking images from the rover’s main camera spotted a small crater that seemed to contain material with a color and luster unlike that of the surrounding lunar surface.

The drive team, excited by the discovery, called in their lunar scientists. Together, the teams decided to postpone Yutu-2’s plans to continue west and instead ordered the rover to check out the strange material.


Yutu-2 found a strangely-colored substance in a crater on the far side of the moon.

With the help of obstacle-avoidance cameras, Yutu-2 carefully approached the crater and then targeted the unusually colored material and its surroundings. The rover examined both areas with its Visible and Near-Infrared Spectrometer (VNIS), which detects light that is scattered or reflected off materials to reveal their makeup.

VNIS is the same instrument that detected tantalizing evidence of material originating from the lunar mantle in the regolith of Von Kármán crater, a discovery Chinese scientists announced in May.

So far, mission scientists haven’t offered any indication as to the nature of the colored substance and have said only that it is “gel-like” and has an “unusual color.” One possible explanation, outside researchers suggested, is that the substance is melt glass created from meteorites striking the surface of the moon.

Yutu-2’s discovery isn’t scientists’ first lunar surprise, however. Apollo 17 astronaut and geologist Harrison Schmitt discovered orange-colored soil near the mission’s Taurus-Littrow landing site in 1972, prompting excitement from both Schmitt and his moonwalk colleague, Gene Cernan. Lunar geologists eventually concluded that the orange soil was created during an explosive volcanic eruption 3.64 billion years ago.


Strange orange soil was discovered on the moon by the Apollo 17 mission in 1972.

Chang’e-4 launched in early December 2018, and made the first-ever soft landing on the far side of the moon on Jan. 3. The Yutu-2 rover had covered a total of 890 feet (271 meters) by the end of lunar day 8.

The Chang’e-4 lander and Yutu-2 rover powered down for the end of lunar day 8 on Aug. 7, and began their ninth lunar day over the weekend. The Yutu-2 rover woke up at 8:42 p.m. EDT on Aug. 23 (00:42 GMT Aug. 24), and the lander followed the next day, at 8:10 p.m. (00:10 GMT).

https://www.space.com/china-far-side-moon-rover-strange-substance.html

Thanks to Kebmodee for bringing this to the It’s Interesting community.

During lunar day 9, Yutu-2 will continue its journey west, take a precautionary six-day nap around local noontime, and power down for a ninth lunar night around Sept. 5, about 24 hours hours ahead of local sunset.