Thursday, December 13, 2018

NASA's OSIRIS-REx Spacecraft Discovers Water on Asteroid

   Newly analyzed data from NASA's Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer (OSIRIS-REx) has revealed the presence of water locked within the clays of the asteroid Bennu.
   Since the beginning of the mission's approach phase in mid-August, the science team has been using three instruments on the spacecraft to begin making preliminary scientific observations of the asteroid from afar.
   Data obtained from the spacecraft's two spectrometers revealed the presence of molecules that contain oxygen and hydrogen atoms bonded together, known as 'hydroxyls'. It is currently hypothesized that these hydroxyl groups exist throughout the asteroid in water-bearing clay minerals. This indicates that that at some point in its history, Benu's rocky material interacted with water.
  “The presence of hydrated minerals across the asteroid confirms that Bennu, a remnant from early in the formation of the solar system, is an excellent specimen for the OSIRIS-REx mission to study the composition of primitive volatiles and organics,” said Amy Simon, OVIRS deputy instrument scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “When samples of this material are returned by the mission to Earth in 2023, scientists will receive a treasure trove of new information about the history and evolution of our solar system.”
Image of asteroid Bennu photographed on Dec 2 via NASA/Goddard/University of Arizona

Tuesday, December 11, 2018

NASA's Voyager 2 Enters Interstellar Space

    In a news conference yesterday, NASA announced that its Voyager 2 probe exited the heliosphere - the protective bubble composed of particles from the solar wind created by our Sun. This marks the second time in history in which a human-made object has left the near solar system.
    Comparing data gathered using different instruments on the spacecraft, scientists realized that the probe crossed the boundary on November 5. Although Voyager 1 made this crossing six years ago, Voyager 2 will be able to provide unique observations through its still-functioning array of instruments unlike its predecessor.
    Scientists realized that the spacecraft left the solar system when Voyager 2's Plasma Science Experiment (PLS) observed a steep decline in the speed of the solar wind particles on Nov. 5. Since that time, this instrument has detected virtually no solar wind flow in its environment around Voyager. 
 
 
     "Working on Voyager makes me feel like an explorer, because everything we're seeing is new," said John Richardson, principal investigator for the PLS instrument and a principal research scientist at the Massachusetts Institute of Technology in Cambridge. "Even though Voyager 1 crossed the heliopause in 2012, it did so at a different place and a different time, and without the PLS data. So we're still seeing things that no one has seen before."
    Although both probes have crossed the heliosphere, these two spacecraft have not left the solar system entirely. The boundary of the solar system is considered to be beyond the outer edge of the Oort Cloud. The distance of this collection of small objects under the gravity of the Sun is currently known, but it is estimated that it may begin 1,000 astronomical units (AU) from the Sun and extend to over 100,000 AU.

Image Credit: NASA/JPL-Caltech

Sunday, December 9, 2018

MIT Researchers Develop Renewable Energy Storage System Using Liquid Silicon

    Researchers at MIT have released a conceptual design for a renewable energy system capable of storing extra electricity from solar and wind power that could be released back on demand.
    The design involves storing excess electricity in the form of heat in large tanks of molten silicon and then converting the light from the glowing material back into electricity when required. The engineers investigating this design state that such a system would cost significantly less than lithium-ion batteries, an alternative method to store renewable energy. Furthermore, it is estimated that this system would cost half as much as pumped hydroelectric storage, the cheapest form of grid-scale energy storage currently used.
    This design is based on an existing model of renewable energy called concentrated solar power. Unlike conventional solar plants, concentrated solar power utilizes fields of huge mirrors that concentrate sunlight onto a central tower. There, light is converted into heat that is eventually turned into electricity.
    Concentrated solar plants store this heat energy in big tanks filled with molten salt heated at temperatures exceeding 500 degrees Celsius. When electricity is needed, this salt is pumped through a heat exchanger that converts the heat into steam which in turn powers a electrical turbine.
    What sets this system apart involves a few factors including the following:
- Silicon is used instead of salt as it has the highest heat tolerance on record. This tolerance creates a more efficient system that can still be stored safely in graphite tanks that withstand corrosion.
- Instead of mirrors and a central tower, the storage system converts electricity generated by a renewable source (let it be sunlight, wind) into thermal energy through joule heating (by passing current through a heating element)
    The following is an excerpt from MIT News detailing the concept in action:
    The system would consist of a large, heavily insulated, 10-meter-wide tank made from graphite and filled with liquid silicon, kept at a “cold” temperature of almost 3,500 degrees Fahrenheit. A bank of tubes, exposed to heating elements, then connects this cold tank to a second, “hot” tank. When electricity from the town’s solar cells comes into the system, this energy is converted to heat in the heating elements. Meanwhile, liquid silicon is pumped out of the cold tank and further heats up as it passes through the bank of tubes exposed to the heating elements, and into the hot tank, where the thermal energy is now stored at a much higher temperature of about 4,300 F.

    When electricity is needed, say, after the sun has set, the hot liquid silicon — so hot that it’s glowing white — is pumped through an array of tubes that emit that light. Specialized solar cells, known as multijunction photovoltaics, then turn that light into electricity, which can be supplied to the town’s grid. The now-cooled silicon can be pumped back into the cold tank until the next round of storage — acting effectively as a large rechargeable battery.

     “Even if we wanted to run the grid on renewable right now we couldn’t, because you’d need fossil-fuelled turbines to make up for the fact that the renewable supply cannot be dispatched on demand,” said Asegun Henry, the Robert N. Noyce Career Development Associate Professor in the Department of Mechanical Engineering. “We’re developing a new technology that, if successful, would solve this most important and critical problem in energy and climate change, namely, the storage problem.”

Read the full press release at: http://news.mit.edu/2018/liquid-silicon-store-renewable-energy-1206

Saturday, December 8, 2018

China Launches Chang'e-4 Mission to Far Side of the Moon

   At about 2:23 A.M. local time on Saturday, China launched a rocket carrying the Chang'e-4 lunar lander from Xichang Satellite Launch Centre in southern China. An unofficial live stream record near the site documented the rising of the rocket as it made its journey to the Moon.
   Chang'e-4 contains a 2,400 pound lander and 300-pound rover based mainly on the preexisting Chinese moon lander Chang'e-3 that touched down in 2013.
   This rover is set to land in the 110-mile-wide Von Kármán crater located on the far side of the moon.This crater is found in the South Pole-Aitken basin, a gigantic, 1,600-mile-wide crater near the bottom of the moon.
   Through a collaboration with entities such as Kiel University in Germany and the Swedish Institute of Space Physics, the instruments will investigate the structure of the rocks in the area to study the effects of the solar wind on the lunar surface.
   In addition, Chang'e-4 will also make radio astronomy observations from the far side of the moon to understand the lack of effects of noise and interference which are present on Earth. This will be paired with a biological payload that will see if plants seeds are capable of germinating and silkworm eggs are able to hatch in the moon's low gravity.
   Although China's space agency has not announced a landing date, it is currently believed by some experts that the lander will touch down around the first week of January.
 
 Read the full story at:
 
Image Credit: Chinese Academy of Sciences

Thursday, December 6, 2018

Bizarre 'dark fluid' with negative mass could dominate the universe – what my research suggests


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Bubbles can be modelled as having a negative mass. Mike Lewinski/Flickr, CC BY-ND
Jamie Farnes, University of Oxford

It’s embarrassing, but astrophysicists are the first to admit it. Our best theoretical model can only explain 5% of the universe. The remaining 95% is famously made up almost entirely of invisible, unknown material dubbed dark energy and dark matter. So even though there are a billion trillion stars in the observable universe, they are actually extremely rare.
The two mysterious dark substances can only be inferred from gravitational effects. Dark matter may be an invisible material, but it exerts a gravitational force on surrounding matter that we can measure. Dark energy is a repulsive force that makes the universe expand at an accelerating rate. The two have always been treated as separate phenomena. But my new study, published in Astronomy and Astrophysics, suggests they may both be part of the same strange concept – a single, unified “dark fluid” of negative masses.
Negative masses are a hypothetical form of matter that would have a type of negative gravity – repelling all other material around them. Unlike familiar positive mass matter, if a negative mass was pushed, it would accelerate towards you rather than away from you.
Negative masses are not a new idea in cosmology. Just like normal matter, negative mass particles would become more spread out as the universe expands – meaning that their repulsive force would become weaker over time. However, studies have shown that the force driving the accelerating expansion of the universe is relentlessly constant. This inconsistency has previously led researchers to abandon this idea. If a dark fluid exists, it should not thin out over time.
In the new study, I propose a modification to Einstein’s theory of general relativity to allow negative masses to not only exist, but to be created continuously. “Matter creation” was already included in an early alternative theory to the Big Bang, known as the Steady State model. The main assumption was that (positive mass) matter was continuously created to replenish material as the universe expands. We now know from observational evidence that this is incorrect. However, that doesn’t mean that negative mass matter can’t be continuously created. I show that this assumed dark fluid is never spread too thinly. Instead it behaves exactly like dark energy.



I also developed a 3D computer model of this hypothetical universe to see if it could also explain the physical nature of dark matter. Dark matter was introduced to explain the fact that galaxies are spinning much faster than our models predict. This implies that some additional invisible matter must be present to prevent them from spinning themselves apart.
My model shows that the surrounding repulsive force from dark fluid can also hold a galaxy together. The gravity from the positive mass galaxy attracts negative masses from all directions, and as the negative mass fluid comes nearer to the galaxy it in turn exerts a stronger repulsive force onto the galaxy that allows it to spin at higher speeds without flying apart. It therefore appears that a simple minus sign may solve one of the longest standing problems in physics.

Is the universe really this weird?

One may argue that this sounds a little far fetched. But while negative masses are bizarre, they are considerably less strange than you may immediately think. For starters, these effects may only seem peculiar and unfamiliar to us, as we reside in a region dominated by positive mass.
Whether physically real or not, negative masses already have a theoretical role in a vast number of areas. Air bubbles in water can be modelled as having a negative mass. Recent laboratory research has also generated particles that behave exactly as they would if they had negative mass.
And physicists are already comfortable with the concept of negative energy density. According to quantum mechanics, empty space is made up of a field of fluctuating background energy that can be negative in places – giving rise to waves and virtual particles that pop into and out of existence. This can even create a tiny force that can be measured in the lab.
The new study could help solve many problems in modern physics. String theory, which is our best hope for unifying the physics of the quantum world with Einstein’s theory of the cosmos, is currently seen as being incompatible with observational evidence. However, string theory does suggest that the energy in empty space must be negative, which corroborates the theoretical expectations for a negative mass dark fluid.
Moreover, the team behind the groundbreaking discovery of an accelerating universe surprisingly detected evidence for a negative mass cosmology, but took the reasonable precaution of interpreting these controversial findings as “unphysical”.
The theory could also solve the problem of measuring the universe’s expansion. This is explained by the Hubble-Lemaître Law, the observation that more distant galaxies are moving away at a faster rate. The relationship between the speed and the distance of a galaxy is set by the “Hubble constant”, but measurements of it have continued to vary. This has led to a crisis in cosmology. Fortunately, a negative mass cosmology mathematically predicts that the Hubble “constant” should vary over time. Clearly, there is evidence that this weird and unconventional new theory deserves our scientific attention.

Where to go from here

The creator of the field of cosmology, Albert Einstein, did – along with other scientists including Stephen Hawking – consider negative masses. In fact, in 1918 Einstein even wrote that his theory of general relativity may have to be modified to include them.
Despite these efforts, a negative mass cosmology could be wrong. The theory seems to provide answers to so many currently open questions that scientists will – quite rightly – be rather suspicious. However, it is often the out-of-the-box ideas that provide answers to longstanding problems. The strong accumulating evidence has now grown to the point that we must consider this unusual possibility.
The largest telescope to ever be built – the Square Kilometre Array (SKA) – will measure the distribution of galaxies throughout the history of the universe. I’m planning to use the SKA to compare its observations to theoretical predictions for both a negative mass cosmology and the standard one – helping to ultimately prove whether negative masses exist in our reality.

The Square Kilometre Array may provide answers. SKA Project Development Office and Swinburne Astronomy Productions, CC BY-SA

What is clear is that this new theory generates a wealth of new questions. So as with all scientific discoveries, the adventure does not end here. In fact, the quest to understand the true nature of this beautiful, unified, and – perhaps polarised – universe has only just begun.
Jamie Farnes, Research Associate & Astrophysicist based at Oxford's e-Research Centre, University of Oxford

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Sunday, December 2, 2018

NASA Working with Yuri Milner to Launch Mission to Enceladus

    In documents recently acquired by news agency New Scientist and reported by Gizmodo, NASA will be working with billionaire entrepreneur and physicist Yuri Milner to launch the first ever private deep-space mission. This project will look for life, if it exists, on Saturn's moon Enceladus.
    According to the documents, NASA and Milner's non-profit Breakthrough Starshot Foundation will be working on scientific, technical and financial plans for this mission. NASA has committed over $70,000 to produce a concept study for the flyby mission. This money won't be paid to Breakthrough but represents the agency's staffing costs for the project. Breakthrough Initiatives would lead and pay for an Enceladus fly-by mission, with consulting from NASA.
    Icy moons throughout the Jupiter and Saturn moon systems are thought of as potential candidates for alien life. Jupiter's moon Europa has evidence of water in the form of plumes spewing water vapour out of the cracks on its surface.
    Similarly, Enceladus has evidence of a warm ocean and even complex organic molecules. All of this data was obtained during the Cassini Space mission funded by NASA and ESA. Even though it orbits Saturn which is even farther from Earth and Jupiter, life may have evolved deep within the moon around heat emanating from volcanic vents.

Read the full press release here: https://gizmodo.com/report-nasa-and-yuri-milner-working-together-on-life-h-1830309201

Tuesday, November 27, 2018

Chinese Researcher Claims He Created First Gene-Edited Babies

    A Chinese researcher claimed on Monday that he helped to create the world's first genetically edited babies - twin girls born this month whose DNA he altered using the powerful tool known as CRISPR.
    The researcher, He Jiankui of Shenzhen, said he altered embryos for seven couples during fertility treatments, resulting in one pregnancy thus far. He claimed that his goal was not to cure or prevent inherited diseases, but to give the ability to resist possible future infections from HIV, the AIDS virus.
    As of the time of publication, there is no independent confirmation of He's claim and it has not been published in any peer-reviewed journals. He revealed the news in Hong Kong yesterday to one of the organizers of an international conference on gene editing beginning today prior to an interview with the Associated Press.
    In recent years, scientists have developed a relatively easy way to edit genes. The tool, called CRISPR-cas9, makes it possible to operate on DNA to add an additional gene or disable one. Up until now, CRISPR has been used primarily to create cell and animal models. These are used to accelerate research into diseases such as cancer and mental illness.
    In the United States, editing sperm, eggs or embryos (permitting any gene edits inheritable) is illegal except for lab research. China outlaws human cloning but not specifically gene editing.
The bulk of the scientific community believe that gene editing in humans is too unsafe to try and some scientists have denounced this feat as human experimentation.
He Jiankui, left, and Zhou Xiaqin work on a computer at a laboratory in Shenzhen. (AP Photo/Mark Schiefelbein)
    It’s “unconscionable ... an experiment on human beings that is not morally or ethically defensible,” said Dr. Kiran Musunuru, a University of Pennsylvania gene editing expert and editor of a genetics journal.
    “This is far too premature,” said Dr. Eric Topol, who heads the Scripps Research Translational Institute in California. “We’re dealing with the operating instructions of a human being. It’s a big deal.”
     “I feel a strong responsibility that it’s not just to make a first, but also make it an example,” He told the Associated Press. “Society will decide what to do next” in terms of allowing or forbidding such science. 
Image Credit: (AP Photo/Mark Schiefelbein)