Newly lab-made metallic hydrogen could revolutionize spaceflight

After almost one century of being predicted by physicists, metallic hydrogen is claimed to be a reality according to two scientists from Harvard University, Professor Isaac Silvera and Dr. Ranga Dias. The scientists described this rare creation in a paper published in Science on January 26.

“This is the holy grail of high-pressure physics,” Professor Silvera explained. “It’s the first-ever sample of metallic hydrogen on Earth, so when you’re looking at it, you’re looking at something that’s never existed before.”

They managed to create the rarest, and possibly most valuable, material on the planet by squeezing it to incredibly high pressures between two ultrapure diamonds. The amount of pressure needed was immense – more than is found at the center of the Earth.

metallic-hydrogen

Credit: Ranga Dias; Isaac Silvera

At the moment scientists don’t know much about the material’s properties. The tiny piece of metal can only be seen through two diamonds that were used to crush liquid hydrogen at a temperature far below freezing.

The next risky step is to establish whether the metal is stable at normal pressures and temperatures. If it succeeds, metallic hydrogen could transform humanity’s efforts to explore our solar system by providing a form of rocket fuel nearly four times more powerful than the best available today.

Professor Silvera commented: “We would be able to put rockets into orbit with only one stage, versus two, and could send up larger payloads, so it could be very important.”

On the other hand, some experts are having doubts about that. They argue that the shiny material may be something else entirely – like aluminum oxide, which is known to coat the diamonds that sit in the anvil and may become shiny under high pressure.

Griffin, from Independent UK news, say that scientists have also questioned why the team published their results before they have taken the material out of the anvil, and will get to work on doing other experiments. But the researchers claimed in press materials that they had done so in order to publicize their “breakthrough event”, and that further experiments would shed more light.

It’s a tremendous achievement, and even if it only exists in this diamond anvil cell at high pressure, it’s a very fundamental and transformative discovery”, Professor Silvera said.

 

Sources:

Ghose, T. (2017). Lab-Made ‘Metallic Hydrogen’ Could Revolutionize Rocket Fuel. Retrieved from: http://bit.ly/2jGM5xD

Johnston, I. (2017). Hydrogen turned into metal in stunning act of alchemy that could revolutionise technology and spaceflight. Retrieved from: http://ind.pn/2k6kjNT

Griffin, A. (2017). Physicists might have made a mistake in claiming to have turned hydrogen into a metal, experts say. Retrieved from: http://ind.pn/2jbtAoU

New study on Ceres’ surface shows: asteroids might be camouflaged

Ceres is the largest object in the asteroid belt and for being much larger than the rest of the other objects it was classified as a dwarf planet in 2006. Since first discovered, in 1801, Ceres has been surprising scientists and the latest study on its surface just deepened the mystery around the dwarf planet.

Using data primarily gathered by SOFIA, NASA’s Stratospheric Observatory for Infrared Astronomy with DLR partnership, a team of astronomers has detected the presence of substantial amounts of material on the surface of Ceres that appears to be fragments of other asteroids. This is contrary to the currently accepted surface composition classification of Ceres, suggesting that the largest body in the asteroid belt between Mars and Jupiter is cloaked by material that has partially disguised its real makeup.

“We find that the outer few microns of the surface is partially coated with dry particles,” says Franck Marchis, senior planetary astronomer at the SETI Institute. “But they don’t come from Ceres itself. They’re debris from asteroid impacts that probably occurred tens of millions of years ago.”

Ceres is considered to be both an asteroid and a dwarf planet, the only dwarf planet located in the inner solar system. Astronomers have classified Ceres, as well as 75 percent of all asteroids, as belonging to composition class “C” based on their similar colors. But the mid-infrared spectra from SOFIA show that Ceres differs substantially from C-type asteroids in nearby orbits, challenging the conventional understanding of the relationship between Ceres and smaller asteroids.

“By analyzing the spectral properties of Ceres we have detected a layer of fine particles of a dry silicate called pyroxene. Models of Ceres based on data collected by NASA’s Dawn as well as ground-based telescopes indicated substantial amounts of water-bearing minerals such as clays and carbonates,” explains Pierre Vernazza, research scientist in the Laboratoire d’Astrophysique de Marseille. “Only the mid-infrared observations made using SOFIA were able to show that both types of material are present on the surface of Ceres.”

asteroid belt SOFIA pyroxene asteroide camouflage ceres surface

Ceres’ surface is contaminated by a significant amount of dry material while its the area below the crust contains essentially water-bearing materials. The mid-infrared observations revealed the presence of dry pyroxene on the surface probably coming from interplanetary dust particles. The Internal structure of the Dwarf Planet Ceres was derived from the NASA Dawn spacecraft data. (Credit: SETI Institute)

To identify where the pyroxene on the surface of Ceres came from, Vernazza and his collaborators, including researchers from the SETI Institute and NASA’s Jet Propulsion Laboratory, turned to interplanetary dust particles (IDPs) that are commonly seen as meteors when they streak through Earth’s atmosphere. The research team had previously shown that IDPs blasted into space by asteroid collisions are an important source of material accumulated on the surfaces of other asteroids. The implication is that a coating of IDPs has caused Ceres to mimic the coloration of some of its dry and rocky neighbors.

Ceres and asteroids are not the only instance in which material transported from elsewhere has affected the surfaces of solar system bodies. Dramatic examples include the red material seen by New Horizons on Pluto’s moon Charon and Saturn’s two-faced moon Iapetus. Planetary scientists also hypothesize that material from comets and asteroids provided a final veneer to the then-forming Earth – a coating that included substantial amounts of water plus the organic substances of the biosphere.

This study resolves a long standing question about whether surface material accurately reflects the intrinsic composition of an asteroid. These results show that by extending observations to the mid-infrared, one can better identify the composition of an asteroid. According to Vernazza, “the detection of some ammoniated clays mixed with the watery clays on Ceres raises the possibility that the dwarf planet might have formed in the outer reaches of the solar system and somehow migrated to its current location.”

“SOFIA, is the only observatory, currently operating or planned, that can make such observations, essential to understanding the true nature of these objects” says Marchis. “The bottom line is that seeing is not believing when it comes to asteroids. We shouldn’t judge these objects by their covers, as it were.”

 

Source: SETI Institute Press Release

Galaxies being killed by ram-pressure stripping phenomenon

New studies revealed that the so-called ram-pressure stripping phenomenon is more prevalent than previously thought and it is killing entire galaxies.

A global team of researchers, based at the International Centre for Radio Astronomy Research (ICRAR), led by the astronomer Toby Brown, studied about 11,000 galaxies and found out that their gas (the lifeblood for star formation) is being violently stripped away on a widespread scale throughout the local Universe.

Brown said removing the gas from galaxies leaves them unable to form new stars. “It dictates the life of the galaxy because the existing stars will cool off and grow old,” he said. “If you remove the fuel for star formation then you effectively kill the galaxy and turn it into a dead object.”

galaxy stripping ram-pressure

An artist’s impression showing the increasing effect of ram-pressure stripping in removing gas from galaxies, sending them to an early death. Credit: ICRAR, NASA, ESA, the Hubble Heritage Team (STScI/AURA)

The leader of the study also said the image we paint as astronomers is that galaxies are embedded in clouds of dark matter that we call dark matter halos.

Dark matter is the mysterious material that despite being invisible accounts for roughly 27 per cent of our Universe, while ordinary matter makes up just 5 per cent. The remaining 68 per cent is dark energy.

“During their lifetimes, galaxies can inhabit halos of different sizes, ranging from masses typical of our own Milky Way to halos thousands of times more massive,” Brown said.

He also explains: “as galaxies fall through these larger halos, the superheated intergalactic plasma between them removes their gas in a fast-acting process called ram-pressure stripping.”

“We’ve found this removal of gas by stripping is potentially the dominant way galaxies are quenched by their surrounds, meaning their gas is removed and star formation shuts down”, he complements.

“What ram-pressure stripping does is bop the galaxy on the head and remove its gas very quickly—of the order of tens of millions of years—and astronomically speaking that’s very fast.”

Animation: Ram Pressure Stripping of Galaxies

An animation showing how ram-pressure stripping removes gas from galaxies, sending them to an early death. Credit: ICRAR, NASA, ESA, the Hubble Heritage Team (STScI/AURA)

 

Source: http://www.icrar.org/galaxy-murder-mystery/

Podcast Interview with NEOShield-2 Project

Last week Dr. Albert Falke and Dr. Line Drube were interviewed by Sean Gill, creator of the PanFuture Society website.

In the interview, Dr. Albert and Dr. Line give more technical details about the NEOShield-2 project and also clarify what is the real threat from asteroids and how asteroid threat can be mitigated.

They also talk about long-period comets, deflecting asteroids, kinetic impactor and raise the importance of the project.

Be full informed checking the interview on the player below.