Finally, the Missing Link in Planetary Formation!

Finally, the Missing Link in Planetary Formation!

The theory of how planets form has been something of an enduring mystery for scientists. While astronomers have a pretty good understanding of where planetary systems comes from – i.e. protoplanetary disks of dust and gas around new stars (aka. “Nebular Theory“) – a complete understanding of how these discs eventually become objects large enough to collapse under their own gravity has remained elusive.

But thanks to a new study by a team of researchers from France, Australia and the UK, it seems that the missing piece of the puzzle may finally have been found. Using a series of simulations, these researchers have shown how “dust traps” – i.e. regions where pebble-sized fragments could collect and stick together – are common enough to allow for the formation of planetesimals.

Their study, titled “Self-Induced Dust Traps: Overcoming Planet Formation Barriers“, appeared recently in the Monthly Notices of the Royal Astronomical Society. Led by Dr. Jean-Francois Gonzalez – of the Lyon Astrophysics Research Center (CRAL) in France – the team examined the troublesome middle-stage of planetary formation that has plagued scientists.

An image of a protoplanetary disk, made using results from the new model, after the formation of a spontaneous dust trap, visible as a bright dust ring. Gas is depicted in blue and dust in red. Credit: Jean-Francois Gonzalez.

Until recently, the process by which protoplanetary disks of dust and gas aggregate to form peddle-sized objects, and the process by which planetesimals (objects that are one hundred meters or more in diameter) form planetary cores, have been well understood. But the process that bridges these two – where pebbles come together to form planetesimals – has remained unknown.

Part of the problem has been the fact that the Solar System, which has been our only frame of reference for centuries, formed billions of years ago. But thanks to recent discoveries (3453 confirmed exoplanets and counting), astronomers have had lots of opportunities to study other systems that are in various stages of formation. As Dr. Gonzalez explained in a Royal Astronomical Society press release:

“Until now we have struggled to explain how pebbles can come together to form planets, and yet we’ve now discovered huge numbers of planets in orbit around other stars. That set us thinking about how to solve this mystery.”

In the past, astronomers believed that “dust traps” – which are integral to planet formation – could only exist within certain environments. In these high-pressure regions, large grains of dust are slowed down to the point where they are able to come together. These regions are extremely important since they counteract the two main obstacles to planetary formation, which are drag and high-speed collisions.

Artist’s impression of the planets in our solar system, along with the Sun (at bottom). Credit: NASA

Drag is caused by the effect gas has on dust grains, which causes them to slow down and eventually drift into the central star (where they are consumed). As for high-speed collisions, this is what causes large pebbles to smash into each other and break apart, thus reversing the aggregation process. Dust traps are therefore needed to ensure that dust grains are slowed down just enough so that they won’t annihilate each other when they collide.

To see just how common these dust traps were, Dr. Gonzalez and his colleagues conducted a series of computer simulations that took into account how dust in a protoplanetary disk could exert drag on the gas component – a process known as “aerodynamic drag back-reaction”. Whereas gas typically has an arresting influence on dust particles, in particularly dusty rings, the opposite can be true.

This effect has been largely ignored by astronomers up until recently, since its generally quite negligible. But as the team noted, it is an important factor in protoplanetary disks, which are known for being incredibly dusty environments. In this scenario, the effect of back-reaction is to slow inward-moving dust grains and push gas outwards where it forms high-pressure regions – i.e. “dust traps”.

Once they accounted for these effects, their simulations showed how planets form in three basic stages. In the first stage, dust grains grow in size and move inwards towards the central star. In the second, the now pebble-sized larger grains accumulate and slow down. In the third and final stage, the gas is pushed outwards by the back-reaction, creating the dust trap regions where it accumulates.

Illustration showing the stages of the formation mechanism for dust traps. Credit: © Volker Schurbert.

These traps then allow the pebbles to aggregate to form planetesimals, and eventually planet-sized worlds. With this model, astronomers now have a solid idea of how planetary formation goes from dusty disks to planetesimals coming together. In addition to resolving a key question as to how the Solar System came to be, this sort of research could prove vital in the study of exoplanets.

Ground-based and space-based observatories have already noted the presence of dark and bright rings that are forming in protoplanetary disks around distant stars – which are believed to be dust traps. These systems could provide astronomers with a chance to test this new model, as they watch planets slowly come together. As Dr. Gonzalez indicated:

“We were thrilled to discover that, with the right ingredients in place, dust traps can form spontaneously, in a wide range of environments. This is a simple and robust solution to a long standing problem in planet formation.”

Further Reading: Royal Astronomical Society, MNRAS

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You Can’t See the Great Wall of China From Space, But You Can See Their Giant Solar Farm –

You Can’t See the Great Wall of China From Space, But You Can See Their Giant Solar Farm –

While the Great Wall of China is not readily visible from space (we debunked that popular myth here) there are several other human-built structures that actually can be seen from space. And that list is growing, thanks to the large solar farms being built around the world.

The solar farm with the current distinction of being the largest in the world — as of February 2017 – is the Longyangxia Dam Solar Park in China. These new images from NASA’s Landsat 8 satellite show the farm’s blue solar panels prominently standing out on the brown landscape of the western province of Qinghai, China. Reportedly, the solar farm covers 27 square kilometers (10.42 square miles), and consists of nearly 4 million solar panels.

You can see in the image below from 2013 that the farm has been growing over the years. The project has cost the amount of 6 billion yuan ($889.5 million).

The orbital view from April 16, 2013
of the Longyangxia Dam Solar Park in China. Credit: NASA/Landsat 8.

China wants to shed its title of the biggest polluter in the world and is now investing in clean, renewable energy. It has a goal of producing 110 GW of solar power and 210 GW of wind power by the year 2020. That sounds like a lot, but in a country of 1.4 billion people that relies heavily on coal, it amounts to less than 1 percent of the country’s more than 1,500 gigawatts of total power generation capacity, says Inside Climate News.

According to NASA, China is now the world’s largest producer of solar power, however Germany, Japan, and the United States produce more solar power per person.

China has another solar farm in the works that will have a capacity of 2,000 MW when it is finished.

Here’s another view from Landsat 8 of the Longyangxia Dam and lake near the solar farm.

The Longyangxia Dam Solar Park as seen from orbit on January 5, 2017. Credit: NASA/Landsat 8.

Source: Landsat

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Rise of the Super Telescopes: The Overwhelmingly Large Telescope

Rise of the Super Telescopes: The Overwhelmingly Large Telescope

We humans have an insatiable hunger to understand the Universe. As Carl Sagan said, “Understanding is Ecstasy.” But to understand the Universe, we need better and better ways to observe it. And that means one thing: big, huge, enormous telescopes.

In this series we’ll look at 6 of the world’s Super Telescopes:

  • The Giant Magellan Telescope
  • The Overwhelmingly Large Telescope
  • The 30 Meter Telescope
  • The European Extremely Large Telescope
  • The Large Synoptic Survey Telescope
  • The James Webb Space Telescope

The Overwhelmingly Large Telescope

The OWL (Overwhelmingly Large Telescope) was a gargantuan telescope proposed by the European Southern Observatory (ESO). The OWL was going to be a 100 meter monstrosity, which would dwarf anything in operation at the time. Sadly, OWL was eventually cancelled.

For now, anyway.

At the time that OWL was first proposed—in the late 1990’s—scientific studies showed that huge telescopes would be necessary to advance our knowledge. OWL promised to help us unlock the mystery of dark matter, peer back in time to witness the birth of the first stars and galaxies, and to directly image the atmospheres of exoplanets. It’s easy to see why people were excited by OWL.

This image simulates the increased resolving power of the OWL compared to its contemporaries. Image: ESO Telescope Systems Division

By 2005, the OWL study was completed and reviewed by a panel of experts. At that time, the concept was validated as a cost-effective way to build an Extremely Large Telescope (ELT). However, as the wheels kept turning, and a price tag of € 1.5 billion was attached to it, the ESO backed away.

OWL’s design called for a 100 meter diameter mirror, built out of 3264 segments. It would have had unequalled light-gathering capacity, and the ability to resolve details down to a milli-arc second. (A milli-arc second is approximately the size of a dime, placed on top of the Eiffel Tower, and viewed from New York City.) That’s extremely impressive to say the least. And OWL would have operated in both visible light and infrared.

Everything about OWL’s design was modular, in an effort to keep costs down. Image: ESO Telescope Systems Division

The problem with OWL was the cost, not the design feasibility. Engineers still think the design is feasible. In fact, the construction of the mirrors was pretty well-understood, and perhaps the most challenging part of the OWL was the adaptive optics required.

It’s a fact of large telescopes that they have to be constantly adjusted to produce sharp images. This requires adaptive optics. The adaptive optics required for OWL would have pushed the state-of-the-art technology at the time.

Adaptive optics is a method of overcoming the distortions that affect light as they pass through Earth’s atmosphere. For extremely sensitive telescopes like the OWL, the atmosphere of Earth is problematic. The photons coming from the distant reaches of the Universe can be garbled by the atmosphere as they approach the telescope. Telescopes are built on mountain-tops to reduce how much atmosphere photons have to travel through, but that’s not enough.

This video explains how adaptive optics work, and how they helped the Keck telescope make new discoveries.

OWL’s mirror segments would have to be aligned to within a fraction of the wavelength (0.0005 mm for visible light) in order for the telescope to deliver good images. OWL’s adaptive optics would have achieved this by adjusting each of OWL’s 3264 segments rapidly, sometimes several times per second.

OWL’s design called for modularity, or “serial, industrialized fabrication of identical building blocks” to reduce costs. The manufacture of extremely large telescopes is expensive, but so are the transportation costs. All of the components have to be built in engineering and manufacturing centres, then shipped to, and assembled on, fairly remote mountain tops. OWL’s components were designed to be shipped in standard shipping containers, which simplified that aspect of its construction.

This graphic shows the sizes of the world’s telescopes superimposed over the OWL. By Cmglee – Own workiThe source code of this SVG is valid., CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=33613161

In fact, OWL could have begun operation before all of its mirrors were in place, and would have grown in power as more mirror segments were built and integrated. (Other telescopes, like the Giant Magellan Telescope (GMT) will be in operation before all of the mirrors are installed.)

In the end, OWL’s cost became too great, and the project was cancelled. The ESO moved on to the 39.3 meter European Extremely Large Telescope. But all of the work done on the design of OWL was not lost.

This artist’s impression shows the European Extremely Large Telescope (E-ELT) in its enclosure. The E-ELT will be a 39-metre aperture optical and infrared telescope sited on Cerro Armazones in the Chilean Atacama Desert, 20 kilometres from ESO’s Very Large Telescope on Cerro Paranal, which is visible in the distance towards the left. The design for the E-ELT shown here is preliminary. ESO/L. Calçada

Everything that we learn about telescope design trickles down to our next-generation of telescopes. That’s true whether designs like OWL get built or not. We’ll just keep building on our success, and keep building larger and more powerful telescopes.

The adaptive optics that OWL required were a challenge. But huge advances have been made on that front. And in the way of things, the manufacturing costs have likely come down as well.

OWL itself may never be built, but other ‘scopes are on the way. Telescopes like the James Webb Space Telescope, the Giant Magellan Telescope, and the European Extremely Large Telescope hold the same promise that OWL did.

And in the end, the contributions of those and other ‘scopes might surpass those promised by OWL.

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Join the Eclipse MegaMovie 2017 Chronicling the August Total Solar Eclipse

Join the Eclipse MegaMovie 2017 Chronicling the August Total Solar Eclipse

Eclipse Diamond Ring

The November 2012 total solar eclipse as seen from Australia. The Eclipse Megamovie project hopes to capture a similar extended view. Image credit and copyright: Alan Dyer/Amazing Sky Photography.

Ready for the “Great American Eclipse?” We’re now less than six months out from the long-anticipated total solar eclipse spanning the contiguous United States from coast-to-coast. And while folks are scrambling to make last minute plans to stand in the path of totality on Monday, August 21st 2017, a unique project named the Eclipse Megamovie 2017 seeks seeks to document the view across the entire path.

The Project: Sponsored by Google’s Making & Science Initiative and led by Scott McIntosh from the National Center for Atmospheric Research’s High Altitude Observatory and Hugh Hudson from the University of California at Berkeley, the Eclipse Megamovie Project seeks to recruit 1,500 observers stationed across the eclipse path from Oregon to South Carolina. Although individual observers will only experience a maximum totality length of 2 minutes and 40 seconds, the complete span of the Eclipse Megamovie will last 90 minutes, compiled using observer images from coast-to-coast.

Mega movie

Getting ready for the Eclipse Megamovie project. Credit: Eclipse Megamovie Project.

“The movie is a tool for scientific exploration,” Hudson said in a recent University of California at Berkeley press release. “We’ll be collecting this level of data for the first time, from millions of observers, and it will be a valuable archive. But we don’t know what we’ll see or what we’ll learn about the interactions between the chromosphere and the corona.”

One portion of the project will have trained volunteers image the Sun from along the eclipse path using DSLRs, while another portion of the project will feature smartphone users imaging totality using a forthcoming Eclipse Megamovie app for a full length lower resolution movie.

Bikers and Baily’s Beads

The only total solar eclipse for 2017, totality for this eclipse occurs along a 114 kilometer-wide path touching on 12 states. Millions live within an easy day drive of the eclipse path, so expect lots of general public interest leading up to eclipse day. August is RV and camping season, so expect camplots to fill up quickly as well. The eclipse also occurs just over a week after the annual Biker’s Rally in Sturgis, South Dakota, affording motorcyclists a chance to stand in the shadow of the Moon en route to the annual pilgrimage.

Great American Eclipse

The path of the August 21st, 2017 eclipse across the United States. Credit: Michael Zeiler/Eclipse-Maps.

The last total solar eclipse to cross one of the 50 United States graced Hawaii on July 11th, 1991, and the last time the umbra of the Moon touched down over the lower 48 states was on February 26th, 1979 across the United States northwest. But you have to go all the way back over almost a century ago to June 8th, 1918 to find an eclipse featuring totality which exclusively spanned the United States from sea to shining sea.

Observers have chased after the umbra seeking to extend fleeting totality before. Eclipse chasers documented the January 24th, 1925 eclipse from aloft aboard a dirigible over New York City. On June 30th, 1973, a supersonic Concorde flight chased the umbra of the Moon across northern Africa, extending totality out to 74 minutes.

The team was also on hand to perform a dry run test of the Megamovie Project at this past weekend’s annular eclipse which crossed South America, the Southern Atlantic and Africa and reports that the field test of the promised project app by Mark Bender worked admirably, and the Eclipse Megamovie App should be available to the general public soon.

Baily's Beads

A mosaic of the 2016 total solar eclipse, depicting the evolution of Baily’s Beads before and after totality. Image credit and copyright: Steed Joy.

What sort of science can such a project offer? What is left to learn from a total solar eclipse after centuries of scientific study? Well, some of the most accurate measurements of the solar diameter and the size and shape of the Sun have been made during solar eclipses. A long movie may also reveal streamers and development of the solar corona, the ethereal pearly white glowing outer atmosphere surrounding the Sun. About half as bright as a Full Moon, we only get a brief glimpse of the corona during totality. Also, the Eclipse Megamovie will get another shot at the project in April 2024, when another eclipse crosses the United States from Texas to Maine.

The Eclipse Megamovie is taking volunteers now. The gear setup required is simple, and you might have what’s needed to image the eclipse laying around already.

DSLR

Got a tripod-mounted, zoom lens equipped DSLR? Photo by author.

You’ll need a DSLR camera with a sturdy tripod, a zoom or fixed lens of 300mm focal length or better, and an ability to nail down your GPS location and the time to the nearest second. Once the volunteers are selected, training will be provided to include GPS and time stamping images, flat-fielding and more.

Phone apps will readily supply the GPS part. For time, I’d go with with WWV Radio, which broadcasts a continuous audio time hack out of Fort Collins, Colorado. This is in Universal Time, and has an accuracy of better than a second better than online time sources, which occasionally lag due to spurious web connections.

Keep in mind, you’ll be photographing the eclipsed Sun during very brief moments of totality. You’ll need to have approved solar glasses and filters in place during all partial phases leading up to and immediately after the eclipse. The Eclipse Megamovie project also hopes to catch sight of the Bailey’s Beads phenomenon as final streamers of sunlight pour through the lunar valleys, giving the illusion known as the Diamond Ring effect.

TSE2017

An animation of the August 21st, 2017 total solar eclipse. A.T. Sinclair/NASA/GSFC

And us? We’ll be casting our hubris at the Universe and catch the eclipse from Columbia, South Carolina. We’re heeding the advice of veteran eclipse chasers, and simply enjoying our first eclipse, and imaging our second, though we may sneak in a few shots for the Eclipse Megamovie project. Universe Today publisher Fraser Cain and astronomer and AstronomyCast host Pamela Gay will lead a group watching from southern Illinois, and we’ve also heard from many other observers from around the world who’ll be visiting the U.S. the August… where will you be?

And we’ve already got a spot picked out for 2024, as the next total solar eclipse crosses Aroostook County and our hometown of Mapleton, Maine… hey, you can never start planning too early, right?

Get set for an eclipse for the ages, and be sure to contribute to the Eclipse Megamovie Project.

-Read about all eclipses, comets, occultations and more for the year in our guide to 101 Astronomical Events for 2017, free from Universe Today.

-Eclipse… science fiction? Check out our original eclipse-fueled sci-fi tales Exeligmos, Shadowfall, the Syzygy Gambit, Peak Season and more.

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Rise of the Super Telescopes: The Giant Magellan Telescope

Rise of the Super Telescopes: The Giant Magellan Telescope

We humans have an insatiable hunger to understand the Universe. As Carl Sagan said, “Understanding is Ecstasy.” But to understand the Universe, we need better and better ways to observe it. And that means one thing: big, huge, enormous telescopes.

In this series we’ll look at 6 of the world’s Super Telescopes:

  • The Giant Magellan Telescope
  • The Overwhelmingly Large Telescope
  • The 30 Meter Telescope
  • The European Extremely Large Telescope
  • The Large Synoptic Survey Telescope
  • The James Webb Space Telescope

The Giant Magellan Telescope

The Giant Magellan Telescope (GMT) is being built in Chile, at the Las Campanas Observatory, home of the GMT’s predecessors the Magellan Telescopes. The Atacama region of Chile is an excellent location for telescopes because of its superb seeing conditions. It’s a high-altitude desert, so it’s extremely dry and cool there, with little light pollution.

The GMT is being built by the USA, Australia, South Korea, and Brazil. It started facility construction in 2015, and first light should be in the early 2020’s. Segmented mirrors are the peak of technology when it comes to super telescopes, and the GMT is built around this technology.

The heart of the Giant Magellan Telescope is the segmented primary mirror. Image: Giant Magellan Telescope – GMTO Corporation

The GMT’s primary mirror consists of 7 separate mirrors: one central mirror surrounded by 6 other mirrors. Together they form an optical surface that is 24.5 meters (80 ft.) in diameter. That means the GMT will have a total light collecting area of 368 square meters, or almost 4,000 square feet. The GMT will outperform the Hubble Space Telescope by having a resolving power 10 times greater.

There’s a limit to the size of single mirrors that can be built, and the 8.4 meter mirrors in the GMT are at the limits of construction methods. That’s why segmented systems are in use in the GMT, and in other super telescopes being designed and built around the world.

These mirrors are modern feats of engineering. Each one is made of 20 tons of glass, and takes years to build. The first mirror was cast in 2005, and was still being polished 6 years later. In fact, the mirrors are so massive, that they need 6 months to cool when they come out of casting.

They aren’t just flat, simple mirrors. They’re described as potato chips, rather than being flat. They’re aspheric, meaning the mirrors’ faces have steeply curved surfaces. The mirror’s have to have exactly the same curvature in order to perform together, which requires leading-edge manufacturing. The mirrors’ paraboloidal shape has to be polished to an accuracy greater than 25 nanometers. That’s about 1/25th the wavelength of light itself!

In fact, if you took one of the GMT’s mirrors and spread it out from the east coast to the west coast of the USA, the height of the tallest mountain on the mirror would be only 1/2 of one inch.

The plan is for the Giant Magellan Telescope to begin operation with only four of its mirrors. The GMT will also have an extra mirror built, just for contingencies.

The construction of the GMT’s mirrors required entirely new testing methods and equipment to achieve these demanding accuracies. The entire task fell on the University of Arizona’s Richard F. Caris Mirror Lab.

But GMT is more than just its primary mirror. It also has a secondary mirror, which is also segmented. Each one of the secondary mirror’s segments must work in concert with its matching segment on the primary mirror, and the distance from secondary mirror to primary mirror has to be measured within one part in 500 million. That requires exacting engineering for the steel structure of the body of the telescope.

The engineering behind the GMT is extremely demanding, but once it’s in operation, what will it help us learn about the Universe?

“I think the really exciting things will be things that we haven’t yet though of.” -Dr. Robert Kirshner

The GMT will help us tackle multiple mysteries in the Universe, as Dr. Robert Kirshner, of the Harvard-Smithsonian Center for Astrophysics, explains in this video.

The scientific aims of the GMT are well laid out, and there aren’t really any surprises. The goals of the GMT are to increase our understanding of some fundamental aspects of our Universe:

  • Star, planet, and disk formation
  • Extrasolar planetary systems
  • Stellar populations and chemical evolution
  • Galaxy assembly and evolution
  • Fundamental physics
  • First light and reionization

The GMT will collect more light than any other telescope we have, which is why its development is so keenly followed. It will be the first ‘scope to directly image extrasolar planets, which will be enormously exciting. With the GMT, we may be able to see the color of planets, and maybe even weather systems.

We’re accustomed to seeing images of Jupiter’s storm bands, and weather phenomena on other planets in our Solar System, but to be able to see something like that on extra-solar planets will be astounding. That’s something that even the casual space-interested person will immediately be fascinated by. It’s like science fiction come to life.

Of course, we’re still a ways away from any of that happening. With first light not anticipated until the early 2020’s, we’ll have to be very patient.

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Elon Musk Announces Daring SpaceX Dragon Flight Beyond Moon with 2 Private Astronauts in 2018

Elon Musk Announces Daring SpaceX Dragon Flight Beyond Moon with 2 Private Astronauts in 2018

SpaceX CEO Elon Musk announced plans on Feb. 27, 2017 to launch a commercial crew SpaceX Dragon to beyond the Moon and back with two private astronauts in 2018 using a SpaceX Falcon Heavy launching from the Kennedy Space Center. Credit: SpaceX

KENNEDY SPACE CENTER, FL – Breaking News – Elon Musk, billionaire founder and CEO of SpaceX, announced today (27 Feb) a daring plan to launch a commercial manned journey to beyond the Moon and back in 2018 flying aboard an advanced crewed Dragon spacecraft paid for by two private astronauts – at a media telecon.

Note: Check back again for updated details in this breaking news story.

“This is an exciting thing! We have been approached to do a crewed mission to beyond the Moon by some private individuals,” Musk announced at the hastily arranged media telecon just concluded this afternoon which Universe Today was invited to participate in.

The private two person crew would fly aboard a human rated Dragon on a long looping trajectory around the moon and far beyond on an ambitious mission lasting roughly eight days and that could blastoff by late 2018 – if all goes well with rocket and spacecraft currently under development, but not yet flown.

No human has traveled beyond low Earth orbit in more than four decades since Apollo 17 – NASA’s final lunar landing mission in December 1972, and commanded by recently deceased astronaut Gene Cernan.

“Like the Apollo astronauts before them, these individuals will travel into space carrying the hopes and dreams of all humankind, driven by the universal human spirit of exploration,” says SpaceX.

Musk said the private crew of two would launch on a Dragon 2 crew spacecraft atop a SpaceX Falcon Heavy booster from historic pad 39A at the Kennedy Space Center in Florida – the same pad that just reopened for business last week with the successful launch of a cargo Dragon to the International Space Station for NASA

“They are two paying customers.”

“They will fly using a Dragon 2 and Falcon Heavy next year in 2018.”

The Falcon Heavy, once operational, will be the most powerful rocket in the world. Credit: SpaceX

SpaceX is currently developing the commercial crew Dragon spacecraft for missions to transport astronauts to low Earth orbit (LEO) and the International Space Station (ISS) under a NASA funded public/private contract.

The company is developing the triple barreled Falcon Heavy with its own funds – which is derived from the single barreled Falcon 9 rocket funded by NASA.

SpaceX founder and CEO Elon Musk. Credit: Ken Kremer/kenkremer.com

An artist's illustration of the Falcon Heavy rocket. Image: SpaceX

An artist’s illustration of the Falcon Heavy rocket. Image: SpaceX

Historic maiden blastoff of SpaceX Falcon 9 rocket from Launch Complex 39A at the Kennedy Space Center) at 9:38 a.m. EDT on Feb 19, 2017, on Dragon CRS-10 resupply mission to the International Space Station (ISS) for NASA. Credit: Ken Kremer/kenkremer.com

Stay tuned here for Ken’s continuing Earth and Planetary science and human spaceflight news.

Ken Kremer

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This is Actual Science. Crystals at the Earth’s Core Power its Magnetic Field

This is Actual Science. Crystals at the Earth’s Core Power its Magnetic Field

Whether or not a planet has a magnetic field goes a long way towards determining whether or not it is habitable. Whereas Earth has a strong magnetosphere that protects life from harmful radiation and keeps solar wind from stripping away its atmosphere, planet’s like Mars no longer do. Hence why it went from being a world with a thicker atmosphere and liquid water on its surface to the cold, desiccated place it is today.

For this reason, scientists have long sought to understand what powers Earth’s magnetic field. Until now, the consensus has been that it was the dynamo effect created by Earth’s liquid outer core spinning in the opposite direction of Earth’s rotation. However, new research from the Tokyo Institute of Technology suggests that it may actually be due to the presence of crystallization in the Earth’s core.

The research was conducted by scientists from the Earth-Life Science Institute (ELSI) at Tokyo Tech. According to their study – titled “Crystallization of Silicon Dioxide and Compositional Evolution of the Earth’s Core“, which appeared recently in Nature – the energy that drives the Earth’s magnetic field may have more to do with the chemical composition of the Earth’s core.

Using a diamond anvil and a laser, researchers at Tokyo Tech subjected silicon and oxygen samples to conditions similar to the Earth’s core. Credit: Sang-Heon Shim/Arizona State University

Of particular concern for the research team was the rate of which Earth’s core cools over geological time – which has been the subject of debate for some time. And for Dr. Kei Hirose – the director of the Earth-Life Science Institute and lead author on the paper – it has been something of a lifelong pursuit. In a 2013 study, he shared research findings that indicated how the Earth’s core may have cooled more significantly than previously thought.

He and his team concluded that since the Earth’s formation (4.5 billion years ago), the core may have cooled by as much as 1,000 °C (1,832 °F). These findings were rather surprising to the Earth sciences community – leading to what one scientists referred to as the “New Core Heat Paradox“. In short, this rate of core cooling would mean that some other source of energy would be required to sustain the Earth’s geomagnetic field.

On top of this, and related to the issue of core-cooling, were some unresolved questions about the chemical composition of the core. As Dr. Kei Hirose said in a Tokyo Tech press release:

“The core is mostly iron and some nickel, but also contains about 10% of light alloys such as silicon, oxygen, sulfur, carbon, hydrogen, and other compounds. We think that many alloys are simultaneously present, but we don’t know the proportion of each candidate element.”

The magnetic field and electric currents in and around Earth generate complex forces that have immeasurable impact on every day life. Credit: ESA/ATG medialab

In order to resolve this, Hirose and his colleagues at ELSI conducted a series of experiments where various alloys were subjected to heat and pressure conditions similar to that in the Earth’s interior. This consisted of using a diamond anvil to squeeze dust-sized alloy samples to simulate high pressure conditions, and then heating them with a laser beam until they reached extreme temperatures.

In the past, research into iron alloys in the core have focused predominantly on either iron-silicon alloys or iron-oxide at high pressures. But for the sake of their experiments, Hirose and his colleagues decided to focus on the combination of silicon and oxygen – which are believed to exist in the outer core – and examining the results with an electron microscope.

What the researchers found was that under conditions of extreme pressure and heat, samples of silicon and oxygen combined to form silicon dioxide crystals – which were similar in composition to mineral quartz found in the Earth’s crust. Ergo, the study showed that the crystallization of silicon dioxide in the outer core would have released enough buoyancy to power core convection and a dynamo effect from as early on as the Hadean eon onward.

As John Hernlund, also a member of ELSI and a co-author of the study, explained:

“This result proved important for understanding the energetics and evolution of the core. We were excited because our calculations showed that crystallization of silicon dioxide crystals from the core could provide an immense new energy source for powering the Earth’s magnetic field.”

Cross-section of Mars revealing its inner core. Mars must have one day had such a field, but the energy source that powered it has since shut down. Credit: NASA/JPL/GSFC

This study not only provides evidence to help resolve the so-called “New Core Heat Paradox”, it also may help advance our understanding of what conditions were like during the formation of Earth and the early Solar System. Basically, if silicon and oxygen form crystal of silicon dioxide in the outer core over time, then sooner or later, the process will stop once the core runs out of these elements.

When that happens, we can expect Earth’s magnetic field will suffer, which will have drastic implications for life on Earth. It also helps to put constraints on the concentrations of silicon and oxygen that were present in the core when the Earth first formed, which could go a long way towards informing our theories about Solar System formation.

What’s more, this research may help geophysicists to determine how and when other planets (like Mars, Venus and Mercury) still had magnetic fields (and possibly lead to ideas of how they could be powered up again). It could even help exoplanet-hunting science teams determine which exoplanets have magnetospheres, which would allow us to find out which extra-solar worlds could be habitable.

Further Reading: Tokyo Tech News, Nature.

The post This is Actual Science. Crystals at the Earth’s Core Power its Magnetic Field appeared first on Universe Today.

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Carnival of Space #498

Carnival of Space #498

This week’s Carnival of Space is hosted by Allen Versfeld at his Urban Astronomer blog.

Click here to read Carnival of Space #498.

And if you’re interested in looking back, here’s an archive to the past Carnivals of Space. If you’ve got a space-related blog, you should really join the carnival. Just email an entry to carnivalofspace@gmail.com, and the next host will link to it. It will help get awareness out there about your writing, help you meet others in the space community – and community is what blogging is all about. And if you really want to help out, sign up to be a host. Send an email to the above address.

The post Carnival of Space #498 appeared first on Universe Today.

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NASA Studies Whether to Add Crew to 1st SLS Megarocket Moon Launch in 2019

NASA Studies Whether to Add Crew to 1st SLS Megarocket Moon Launch in 2019

NASA’s Space Launch System rocket will be the most powerful rocket in the world and, with the agency’s Orion spacecraft, will launch America into a new era of exploration to destinations beyond Earth’s orbit. Their first integrated mission is planned as uncrewed, but NASA now is assessing the feasibility of adding crew. Credits: NASA/MSFC

KENNEDY SPACE CENTER, FL – At the request of the new Trump Administration, NASA has initiated a month long study to determine the feasibility of converting the first integrated unmanned launch of the agency’s new Space Launch System (SLS) megarocket and Orion capsule into a crewed mission that would propel two astronauts to the Moon and back by 2019 – 50 years after the first human lunar landing.

Top NASA officials outlined the details of the study at a hastily arranged media teleconference briefing on Friday, Feb 24. It will examine the feasibility of what it would take to add a crew of 2 astronauts to significantly modified maiden SLS/Orion mission hardware and whether a launch could be accomplished technically and safely by the end of 2019.

On Feb. 15, Acting Administrator Robert Lightfoot announced that he had asked Bill Gerstenmaier, associate administrator for NASA’s Human Exploration and Operations Mission Directorate in Washington, to start detailed studies of what it would take to host astronauts inside the Orion capsule on what the agency calls Exploration Mission-1, or EM-1.

Gerstenmaier, joined by Bill Hill, deputy associate administrator for Exploration Systems Development in Washington, at the briefing said a team was quickly assembled and the study is already underway.

They expect the study to be completed in early spring, possibly by late March and it will focus on assessing the possibilities – but not making a conclusion on whether to actually implement changes to the current uncrewed EM-1 flight profile targeted for blastoff later in 2018.

“I want to stress to you this is a feasibility study. So when we get done with this we won’t come out with a hard recommendation, one way or the other,” Gerstenmaier stated.

“We’re going to talk about essentially the advantages and disadvantages of adding crew to EM-1.”

“We were given this task a week ago, appointed a team and have held one telecon.”

“Our priority is to ensure the safe and effective execution of all our planned exploration missions with the Orion spacecraft and Space Launch System rocket,” said Gerstenmaier.

“This is an assessment and not a decision as the primary mission for EM-1 remains an uncrewed flight test.”

Artist concept of the SLS Block 1 configuration on the Mobile Launcher at KSC. Credit: NASA/MSFC

Gerstenmaier further stipulated that the study should focus on determining if a crewed EM-1 could liftoff by the end of 2019. The study team includes one astronaut.

If a change resulted in a maiden SLS/Orion launch date stretching beyond 2019 it has little value – and NASA is best to stick to the current EM-1 flight plan.

The first SLS/Orion crewed flight is slated for Exploration Mission-1 (EM-2) launching in 2021.

“I felt that if we went much beyond 2019, then we might as well fly EM-2 and actually do the plan we’re on,” Gerstenmaier said.

NASA’s current plans call for the unmanned blastoff of Orion EM-1 on the SLS-1 rocket later next year on its first test flight on a 3 week long mission to a distant lunar retrograde orbit. It is slated to occur roughly in the September to November timeframe from Launch Complex 39B at the Kennedy Space Center.

Lightfoot initially revealed the study in a speech to the Space Launch System/Orion Suppliers Conference in Washington, D.C. and an agency wide memo circulated to NASA employees on Feb. 15 – as I reported here.

The Orion EM-1 capsule is currently being manufactured at the Neil Armstrong Operations and Checkout Building at the Kennedy Space Center by prime contractor Lockheed Martin.

Orion crew module pressure vessel for NASA’s Exploration Mission-1 (EM-1) is unveiled for the first time on Feb. 3, 2016 after arrival at the agency’s Kennedy Space Center (KSC) in Florida. It is secured for processing in a test stand called the birdcage in the high bay inside the Neil Armstrong Operations and Checkout (O&C) Building at KSC. Launch to the Moon is slated in 2018 atop the SLS rocket. Credit: Ken Kremer/kenkremer.com

To launch astronauts, Orion EM-1 would require very significant upgrades since it will not have the life support systems, display panels, abort systems and more needed to safely support humans on board.

“We know there are certain systems that needed to be added to EM-1 to add crew,” Gerstenmaier elaborated. “So we have a good, crisp list of all the things we would physically have to change from a hardware standpoint.

In fact since EM-1 assembly is already well underway, some hardware already installed would have to be pulled out to in order to allow access behind to add the life support hardware and other systems, Hill explained.

The EM-1 pressure shell arrived last February as I witnessed and reported here.

Thus adding crew at this latter date in the manufacturing cycle is no easy task and would absolutely require additional time and additional funding to the NASA budget – which as everyone knows is difficult in these tough fiscal times.

“Then we asked the team to take a look at what additional tests would be needed to add crew, what the additional risk would be, and then we also wanted the teams to talk about the benefits of having crew on the first flight,” Gerstenmaier explained.

“It’s going to take a significant amount of money, and money that will be required fairly quickly to implement what we need to do,” Hill stated. “So it’s a question of how we refine the funding levels and the phasing of the funding for the next three years and see where it comes out.”

Hill also stated that NASA would maintain the Interim Cryogenic Propulsion stage for the first flight, and not switch to the more advanced and powerful Exploration Upper Stage (EUS) planned for first use on EM-2.

Furthermore NASA would most move up the AA-2 ascent abort test for Orion to take place before crewed EM-1 mission.

Components of the SLS-1 rocket are being manufactured at NASA’s Michoud Assembly Facility and elsewhere around the country by numerous suppliers.

Michoud is building the huge fuel liquid oxygen/liquid hydrogen SLS core stage fuel tank, derived from the Space Shuttle External Tank (ET) – as I detailed here.

Gerstenmaier noted that Michoud did suffer some damage during the recent tornado strike which will necessitate several months worth of repairs.

The newly assembled first liquid hydrogen tank, also called the qualification test article, for NASA’s new Space Launch System (SLS) heavy lift rocket lies horizontally beside the Vertical Assembly Center robotic weld machine (blue) on July 22, 2016. It was lifted out of the welder (top) after final welding was just completed at NASA’s Michoud Assembly Facility in New Orleans. Credit: Ken Kremer/kenkremer.com

The 2018 launch of NASA’s Orion on the unpiloted EM-1 mission counts as the first joint flight of SLS and Orion, and the first flight of a human rated spacecraft to deep space since the Apollo Moon landing era ended more than 4 decades ago.

If NASA can pull off a 2019 EM-1 human launch it will coincide with the 50th anniversary of Apollo 11 – NASA’s first lunar landing mission manned by Neil Armstrong and Buzz Aldrin, along with Michael Collins.

If crew are added to EM-1 it would essentially adopt the mission profile currently planned for Orion EM-2.

“If the agency decides to put crew on the first flight, the mission profile for Exploration Mission-2 would likely replace it, which is an approximately eight-day mission with a multi-translunar injection with a free return trajectory,” said NASA. It would be similar to Apollo 8 and Apollo 13.

This artist concept depicts the Space Launch System rocket rolling out of the Vehicle Assembly Building at NASA’s Kennedy Space Center. SLS will be the most powerful rocket ever built and will launch the agency’s Orion spacecraft into a new era of exploration to destinations beyond low-Earth orbit. Credits: NASA/Marshall Space Flight Center

Orion is designed to send astronauts deeper into space than ever before, including missions to the Moon, asteroids and the Red Planet.

NASA is developing SLS and Orion for sending humans on a ‘Journey to Mars’ in the 2030s.

They are but the first hardware elements required to carry out such an ambitious initiative.

Looking up from beneath the enlarged exhaust hole of the Mobile Launcher to the 380 foot-tall tower astronauts will ascend as their gateway for missions to the Moon, Asteroids and Mars. The ML will support NASA’s Space Launch System (SLS) and Orion spacecraft during Exploration Mission-1 at NASA’s Kennedy Space Center in Florida. Credit: Ken Kremer/kenkremer.com

Stay tuned here for Ken’s continuing Earth and Planetary science and human spaceflight news.

Ken Kremer

An artist’s interpretation of NASA’s Space Launch System Block 1 configuration with an Orion vehicle. Image: NASA

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