Universe Today

February 9, 2011October 21, 2016 by Matt Williams

What is Fermi Energy?

When it comes to physics, the concept of energy is a tricky thing, subject to many different meanings and dependent on many possible contexts. For example, when speaking of atoms and particles, energy comes in several forms, such as electrical energy, heat energy, and light energy.

But when one gets into the field of quantum mechanics, a far more complex and treacherous realm, things get even trickier. In this realm, scientists rely on concepts such as Fermi Energy, a concept that usually refers to the energy of the highest occupied quantum state in a system of fermions at absolute zero temperature.

Fermions:

Fermions take their name from famed 20th century Italian physicist Enrico Fermi. These are subatomic particles that are usually associated with matter, whereas subatomic particles like bosons are force carriers (associated with gravity, nuclear forces, electromagnetism, etc.) These particles (which can take the form of electrons, protons and neutrons) obey the Pauli Exclusion Principle, which states that no two fermions can occupy the same (one-particle) quantum state.

Neils Bohr's model a nitrogen atom. Credit: britannica.com — *Neils Bohr’s model a nitrogen atom. Credit: britannica.com*

In a system containing many fermions (like electrons in a metal), each fermion will have a different set of quantum numbers. Fermi energy, as a concept, is important in determining the electrical and thermal properties of solids. The value of the Fermi level at absolute zero (-273.15 °C) is called the Fermi energy and is a constant for each solid. The Fermi level changes as the solid is warmed and as electrons are added to or withdrawn from the solid.

Calculating Fermi Energy:

To determine the lowest energy a system of fermions can have (aka. it’s lowest possible Fermi energy), we first group the states into sets with equal energy, and order these sets by increasing energy. Starting with an empty system, we then add particles one at a time, consecutively filling up the unoccupied quantum states with the lowest energy.

When all the particles have been put in, the Fermi energy is the energy of the highest occupied state. What this means is that even if we have extracted all possible energy from a metal by cooling it to near absolute zero temperature (0 kelvin), the electrons in the metal are still moving around. The fastest ones are moving at a velocity corresponding to a kinetic energy equal to the Fermi energy.

Bosons, fermions and other particles after a collsion. Credit: CERN — *Image showing bosons, fermions and other particles created by a high-energy collision. Credit: CERN*

Applications:

The Fermi energy is one of the important concepts of condensed matter physics. It is used, for example, to describe metals, insulators, and semiconductors. It is a very important quantity in the physics of superconductors, in the physics of quantum liquids like low temperature helium (both normal and superfluid 3He), and it is quite important to nuclear physics and to understand the stability of white dwarf stars against gravitational collapse.

Confusingly, the term “Fermi energy” is often used to describe a different but closely-related concept, the Fermi level (also called chemical potential). The Fermi energy and chemical potential are the same at absolute zero, but differ at other temperatures.

We have written many interesting articles about quantum physics here at Universe Today. Here’s What is the Bohr Atomic Model?, Quantum Entanglement Explained, What is the Electron Cloud Model, What is the Double Slit Experiment?, What is Loop Quantum Gravity? and Unifying the Quantum Principle – Flowing Along in Four Dimensions.

If you’d like more info on Fermi Energy, check out these articles from Hyperphysics and Science World.

We’ve also recorded an entire episode of Astronomy Cast all about Quantum Mechanics. Listen here, Episode 138: Quantum Mechanics.

Sources:

February 8, 2011January 19, 2016 by Mark Thompson

In Case of Jerusalem Video, UFO Could Mean “Unidentified Flashlight Objects”

UFO’s are tricky little blighters. Those three letters have caused so much controversy over the years and I find myself, yet again, discussing one of the most misrepresented acronyms in the entire Universe. UFO stands for ‘Unidentified Flying Object’ and, if you have never seen a helicopter before, then its a UFO, its unidentified and flying! Forgive me then when I saw the news on January 28, 2011 of yet another UFO sighting and cries of alien visitors as if it were obvious. Well stop right there…..
Continue reading “In Case of Jerusalem Video, UFO Could Mean “Unidentified Flashlight Objects””

February 8, 2011December 24, 2015 by Nancy Atkinson

Historic Opportunity for Students to Participate on “Extra” Shuttle Mission

Astronaut Jeffrey Williams doing plant cells vs. microgravity experiments aboard the ISS in December 2009. Credit: NASA

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A new opportunity for students to be part of history and fly an experiment on what could be the last space shuttle mission has been announced by the Student Spaceflight Experiments Program (SSEP) for the STS-135, the shuttle mission that might fly in June of 2011.

“We hope to get 50 communities and 100,000 students participating in the initiative which allows grade 5-14 student design of real experiments to fly aboard Atlantis, and engages entire communities,” Dr. Jeff Goldstein, the Director for the National Center for Earth and Space Science Education told Universe Today. “This is very unique opportunity for students and teachers to be part of a high visibility, keystone U.S. national STEM education program of the highest caliber.”

SSEP is a new program that launched in June 2010 by the National Center for Earth and Space Science Education in partnership with NanoRacks, LLC, a company that is working with NASA under a Space Act Agreement as part of the utilization of the International Space Station as a National Laboratory.

The company hopes to stimulate space station research by providing a very low-cost 1 kilogram platform that puts micro-gravity projects within the reach of universities and small companies, as well as elementary and secondary schools through SSEP. So, this is actually a commercial space program and not a NASA program.

This opportunity offers real research done on orbit, with students designing and proposing the experiments to fly in low Earth orbit.

Goldstein said the program is a U.S. national Science, Technology, Engineering, and Mathematics (STEM) education initiative that gives up to 3,200 students across a community—middle and high school students (grades 5-12), and/or undergraduates at 2-year community colleges (grades 13-14)—the ability to fly their own experiments in low Earth orbit, first aboard the final flights of the Space Shuttle, and then later on the International Space Station.

For the STS-134 mission, now scheduled to launch in April 2011, 16 communities were chosen to participate from 447 student team proposals. Goldstein said the 16 selected experiments are now moving through formal NASA Flight Safety review.

But the end of the shuttle mission is not the end of this program – instead it is just the beginning. “This is meant to be a gateway to Phase 2 of the program, which will allow routine access to space for students conducting experiments, said Goldstein. “SSEP was designed to engage and inspire America’s next generation of scientists and engineers through immersion in real science. We believe that ‘student as scientist’ represents the very best in science education.”

What type of experiments would be accepted? Students and teachers should discuss what biological, chemical or physical system they would like to explore with no gravity off for 10 days. Examples of experiments are seed germination cell biology, life cycles of organisms, food preservation, and crystal growth. The SSEP program will help guide the teachers through implementation of the program in their classrooms.

Each participating school district will be provided an experiment slot in an easy-to-use real microgravity research mini-laboratory flying on Space Shuttle Atlantis. The SSEP center will then guide the school districts through an experiment design competition within the grade 5-12 range, which can be conducted across a single school, or district-wide to as many as 3,200 students. Student teams then design real experiments vying for your reserved slot on this historic flight, with designs constrained by mini-laboratory operation.

Other benefits of the program include a customized Blog for students and teachers to report on their program, and a design competition for each school to have a 4-inch x 4-inch emblem that we will fly aboard the Shuttle and returned to the school.

There is uncertainty, however, whether the STS-135 mission will fly. Funding for the additional STS-135 mission was authorized by Congress on September 29, 2010, and the authorization was signed by President Obama. NASA is currently awaiting Congressional allocation of funds for STS-135. On January 20, 2011, NASA formally added STS-135 to its launch schedule. Goldstein said there is now a high probability that STS-135 will indeed fly. But when it flies is the issue.

Because of the timing of when NASA needs to have a list of material that will be used in the experiments so that they can do a flight safety review, the SSEP program needs NASA to slip the launch date from June 28, 2011 until at least August 31, 2011. They fully expect this to occur given the significant launch slips that have occurred for STS-133 and STS-134, and the conversations already taking place in NASA.

But it is now time critical for schools to be able to participate. There is a proposal submission deadline of May 12, 2011. By the end of May, the flight experiments will be selected, so that NASA can be provided with the materials list 3 months in advance of launch.

For more information see the SSEP website

Testimonials for SSEP on STS-134

Watch a video of Dr. Jeff Goldstein talking about SSEP.

February 8, 2011April 26, 2016 by Nancy Atkinson

Ares-1 Rocket Could Be Re-born as “Liberty”

The Liberty launch vehicle combines the proven systems from the Space Shuttle and Ariane 5. (PRNewsFoto/ATK)

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An idea too good to die, or a case of recycle, reuse, reduce? Two rocket companies are joining forces to use part of the Ares-1 rocket and combine it with elements of the Ariane 5 launcher to create a new launch system called Liberty that they say will “close the US human spaceflight gap.” US company ATK (Alliant Techsystems) and the European firm Astrium announced their collaboration today on a 90-meter (300-ft) rocket that would fit under NASA’s Commercial Crew Development-2 (CCDev-2) procurement. The companies say the new rocket could be ready by 2013.

“This team represents the true sense of international partnership in that we looked across borders to find the best for our customers,” said Blake Larson, President of ATK Aerospace Systems Group in a press release. “Together we combine unique flight-proven systems and commercial experience that allows us to offer the market’s most capable launch vehicle along with flexibility to meet a wide variety of emerging needs. Liberty provides greater performance at less cost than any other comparable launch vehicle.”

The partners say Liberty would be much cheaper than the Ares I, because the unfinished upper stage of the Ares I would be replaced with the first stage of the Ariane 5, which has been launched successfully 41 consecutive times. The lower stage of the Liberty, a longer version of the shuttle booster built by ATK, would be almost the same as what was built for Ares-1.

he new Liberty launch vehicle will use existing infrastructure at Kennedy Space Center, such as the Mobile Launcher shown here. (PRNewsFoto/ATK)

Since both stages were designed for human-rating, the collaborators say this “would enable unmatched crew safety.” The team has planned an initial flight by the end of 2013, a second test flight in 2014, and operational capability in 2015.

Liberty would be able to deliver 20,000 kg (44,500 lbs) to the International Space Station’s orbit, which would give it a launch capability to carry any crew vehicle in development. This is less payload capability, however, than the 25-ton payload that the Ares-1 was advertised to deliver to the ISS.

With the announcement of the collaboration (and quick turn-around) the companies are hoping to be the recipient of some of the $200 million in funding NASA is planning to give out in March 2011 to private companies that are developing space taxis. Smaller NewSpace companies like SpaceX and , Orbital, along with big companies Lockheed Martin and Boeing are all vying for the CCDev-2 contracts.

With some space experts and Congress expressing concern about the length of time it might take for commercial companies to provide reliable transportation to space, as well as concerns about relying on the Russian Soyuz vehicles, this new collaboration could fit NASA’s needs nicely. Plus, the collaborators are hoping the new Liberty rocket will be a bargain compared to other contenders. They are targeting a price of $180 million per launch, which is slightly less than the Atlas V rocket launches by the Boeing-Lockheed Martin United Launch Alliance, ($187 million).

The two companies have touted the new rockets’ ability to carry a wide array of spacecraft and satellites.

“The Liberty initiative provides tremendous value because it builds on European Ariane 5 launcher heritage, while allowing NASA to leverage the mature first stage,” said former NASA astronaut Charlie Precourt, Vice President and General Manager of ATK Space Launch Systems. “We will provide unmatched payload performance at a fraction of the cost, and we will launch it from the Kennedy Space Center using facilities that have already been built. This approach allows NASA to utilize the investments that have already been made in our nation’s ground infrastructure and propulsion systems for the Space Exploration Program.”

If NASA chooses the Liberty system and it works well, it could mean that the money NASA spent on the Ares rocket was not wasted after all.

ATK has put together this video about “Liberty”

Source: ATK

February 8, 2011December 24, 2015 by Nancy Atkinson

Interior of Subsurface Cave Imaged on the Moon

The LROC NAC acquired an oblique view of the Marius Hills pit with just the right angle to reveal an overhang, with a pit below, which is about 65 meters in diameter. Credit: NASA/GSFC/Arizona State University.

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Follow-up observations of a potential ‘skylight’ in a lava tube on the Moon has revealed a cavernous lunar pit in the Marius Hills region, with a view of the interior and bottom of the pit. The sun angle, camera angle and lighting conditions were just right for the Lunar Reconnaissance Orbiter camera to look all the way down to the floor of the pit. And this is no small hole in the ground — the LRO team says this pit is about 65 meters in diameter! This latest image confirms this object is actually a subsurface cave; a lava tube close to the surface where part of it has collapsed. These lava tubes could be great locations for lunar bases that could protect human explorers from dangers such as cosmic rays, meteorite impacts, and the extreme temperature differences between the lunar day and night.

This is the fourth time that this particular lunar pit has been imaged. Since LRO is constantly orbiting the Moon and it completes a full cycle of lunar imaging each month, the team can do follow up observations of previous discoveries and re-image targets under different lighting conditions.

An image taken about a year ago showing the dark entrance to the Marius Hills pit. Credit: NASA/GSFC/Arizona State University

Previous images had revealed the dark, cave-like entrance, and another showed part of the pit wall.
For this fourth imaging run, the spacecraft slewed 43° to the east and the solar incidence angle was 34° from vertical. This was just the right angle so that if there actually was an open lava tube extending horizontally its floor would be illuminated.

The LROC team hit paydirt (or pay-regolith, if you will).

With LRO’s Narrow Angle Camera, the team was able to image a few meters under the overhang to show the interior of this sublunarean void. With this oblique angle, they were also able to capture the layered nature of the mare bedrock in the pit walls. These exposed layers give scientists important clues as to how the vast mare were deposited.

The collection of images now verifies this is actually a cavernous subsurface cave. These pits had been predicted to exist, based on the understanding of the geomorphology of mare deposits and lava flow behavior on Earth, but never directly imaged before.

A graphic of the imaging geometry in cross section, which allows a view of the lava tube floor. Arizona State University.

The LROC team will be presenting their findings about this pit and others that have been imaged at the Lunar and Planetary Science Conference. You can read their abstract here. (pdf file).

See more about this new image at the LROC website.

February 8, 2011December 24, 2015 by Vanessa Janek

Universe Could be 250 Times Bigger Than What is Observable

Cosmic Noise — This NASA Hubble Space Telescope image shows the distribution of dark matter in the center of the giant galaxy cluster Abell 1689, containing about 1,000 galaxies and trillions of stars. Credit: NASA, ESA, D. Coe (NASA Jet Propulsion Laboratory/California Institute of Technology, and Space Telescope Science Institute), N. Benitez (Institute of Astrophysics of Andalusia, Spain), T. Broadhurst (University of the Basque Country, Spain), and H. Ford (Johns Hopkins University)

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Our Universe is an enormous place; that’s no secret. What is up for discussion, however, is just how enormous it is. And new research suggests it’s a whopper – over 250 times the size of our observable universe.

Currently, cosmologists believe the Universe takes one of three possible shapes:

1) It is flat, like a Euclidean plane, and spatially infinite.
2) It is open, or curved like a saddle, and spatially infinite.
3) It is closed, or curved like a sphere, and spatially finite.

While most current data favors a flat universe, cosmologists have yet to come to a consensus. In a paper recently submitted to Arxiv, UK scientists Mihran Vardanyan, Roberto Trotta and Joseph Silk present their fix: a mathematical version of Occam’s Razor called Bayesian model averaging. The principle of Occam’s Razor states that the simplest explanation is usually the correct one. In this case, a flat universe represents a simpler geometry than a curved universe. Bayesian averaging takes this consideration into account and averages the data accordingly. Unsurprisingly, the team’s results show that the data best fits a flat, infinite universe.

But what if the Universe turns out to be closed, and thus has a finite size after all? Cosmologists often refer to the Hubble volume – a volume of space that is similar to our visible Universe. Light from any object outside of the Hubble volume will never reach us because the space between us and it is expanding too quickly. According to the team’s analysis, a closed universe would encompass at least 251 Hubble volumes.

That’s quite a bit larger than you might think. Primordial light from just after the birth of the Universe started traveling across the cosmos about 13.75 billion years ago. Since special relativity states that nothing can move faster than a photon, many people misinterpret this to mean that the observable Universe must be 13.75 billion light years across. In fact, it is much larger. Not only has space been expanding since the big bang, but the rate of expansion has been steadily increasing due to the influence of dark energy. Since special relativity doesn’t factor in the expansion of space itself, cosmologists estimate that the oldest photons have travelled a distance of 45 billion light years since the big bang. That means that our observable Universe is on the order of 90 billion light years wide.

To top it all off, it turns out that the team’s size limit of 251 Hubble volumes is a conservative estimate, based on a geometric model that includes inflation. If astronomers were to instead base the size of the Universe solely on the age and distribution of the objects they observe today, they would find that a closed universe encompasses at least 398 Hubble volumes. That’s nearly 400 times the size of everything we can ever hope to see in the Universe!

Given the reality of our current capabilities for observation, to us even a finite universe appears to go on forever.

February 8, 2011April 26, 2016 by Tega Jessa

F6 Tornado

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Everyone knows that tornadoes are among nature’s most powerful and destructive phenomenon on land. Also just like other types of storms tornadoes are ranked by strength. The way that tornadoes are ranked is using the Fujita scale. The Fujita scale is a scale that measures the strength of a tornado by the speed of the winds and the amount of the destruction that it causes. The scale is not perfect in that it is hard to directly measure the speeds of the winds and when looking at damage the guidelines are very general and damage becomes indistinguishable after F3.

The Fujita scale is no longer in use since scientists agreed decommission it in favor of the Enhanced Fujita scale, a more nuanced version of the scale that better ranks tornadoes with detailed guidelines concerning wind and destruction patterns. The Fujita scale is still useful to the average person in giving them a general idea of the strength of a tornado. The interesting thing to look for in the Fujita scale is when it reaches F6 tornado. The F6 is a mythical tornado that you would likely only see in movies or hear of in tall tales. It is similar to the magnitude 10 tornado. Early history may have witnessed such phenomena but they have not occurred in modern times due to more settled climates.

The F6 tornado would be the granddaddy of all tornadoes. It would have wind speeds exceeding 300 miles per hour at maximum and would be able to lift houses from their foundations like Dorothy’s Kansas home in the Wizard of Oz. Car would become ballistic missiles able to hurl at tremendous speeds. However; even if such a tornado existed, it would be hard to identify even with an Enhanced Fujita scale. The damage would look mostly the same as an F5 tornado’s damage. It is thought that the more severe damage would be evidenced by specific funnel marks.

We have written many articles about the tornado for Universe Today. Here’s an article about how tornadoes are formed, and here are some pictures of tornado.

If you’d like more info on F6 tornadoes, check out amazing articles from:
Stormtrack.org
Tornado Project

We’ve also recorded an episode of Astronomy Cast all about planet Earth. Listen here, Episode 51: Earth.

February 7, 2011December 24, 2015 by Nancy Atkinson

Bonanza of Blu-rays to Give Away!

Thanks to the folks at A&E Home Entertainment, we have four different Blu-ray discs to give away to four lucky readers of Universe Today:

All on Blu-ray:

The Universe: Explore The Edges Of The Unknown The Complete Season Five
Ancient Aliens-Season One
Life After People: The Complete Season Two
How Earth Was Made Complete Season One

How to win one?

Just send an email to info@universetoday with “Blu-ray Giveaway” in the subject line, and we’ll randomly choose 4 people to win one of the four discs. The contest goes until Thursday, Feb. 10 at 12 Noon PST.

Below is more info on each Blu-ray title, and click the links to Amazon to find out more.

The Universe Explore The Edges of the Unknown The Complete Season 5

It’s been 50 years since man ventured into the unknown, and the heavens are only now yielding their greatest secrets. Follow in the galactic path of THE UNIVERSE, which this season leads us even further into the world beyond our own.

From robotic rovers on Mars to NASA probes slamming into comets and deep space telescopes capturing violent images of the birth of stars, season five of this illuminating HISTORY™ series explores how these discoveries were made – and who made them. Dramatic CGI and interviews with expert cosmologists, astronomers and astrophysicists bring the history of the heavens down to earth and provide a glimpse into our future.

Ancient Aliens: Season One

Is it possible that intelligent life forms visited Earth thousands of years ago, bringing with them technology that drastically affected the course of history and man’s own development? Presented in the 1968 bestselling book Chariots of the Gods, by Erich von Daniken, the theory of ‘ancient aliens’ rocked people’s beliefs in mankind’s progress. Ancient cave drawings of strange creatures, remains of landing strips in Peru, and Indian texts that describe the ‘flying machines of the gods’ were just a few of the odd archaeological artifacts cited by von Daniken as proof that ancient astronauts were well known to our ancestors. Produced with the exclusive cooperation of von Daniken himself, ANCIENT ALIENS launches all-new expeditions to seek out and evaluate this evidence, with a concentration on discoveries of the last 30 years, including unusual DNA findings on man s evolution and newly decoded artifacts from Egypt to Syria to South America. It is a balanced investigation into a theory some believe cannot be true, but many agree cannot be ignored.

Life After People: The Complete Season Two

What would happen if every human being on Earth disappeared? This isn’t the story of how we might vanish – it is the story of what happens to the world we leave behind. The second season of the fascinating HISTORY™ series LIFE AFTER PEOPLE takes a stunningly graphic journey to a world wiped clean of humanity, using cinematic CGI to reveal – in scientific detail – the fate of every aspect of the man-made world, and how the landscape of our planet would forever change in our absence.

From animal outbreaks to massive structural collapses to hordes of toxins and chemicals unleashed across the globe, LIFE AFTER PEOPLE: THE COMPLETE SEASON TWO reveals what happens in the hours, days, months, and years after people disappear. Welcome to Earth, population zero

How The Earth Was Made: Season One

Spectacular on-location footage, evidence from geologists in the field, and clear, dramatic graphics combine in this stunning 13-part series from HISTORY™ to show how immensely powerful, and at times violent, forces of geology have formed our planet.

From the Great Lakes to Iceland, the San Andreas Fault to Krakatoa, HOW THE EARTH WAS MADE travels the globe to reveal the physical processes that have shaped some of the most well-known locations and geological phenomena in the world. With rocks as their clues and volcanoes, ice sheets, and colliding continents as their suspects, scientists launch a forensic investigation that will help viewers visualize how the earth has evolved and formed over millions of years.

February 7, 2011April 26, 2016 by Carnival of Space

Carnival of Space 183

The Carnival of Space 183 is up at Parallel Spirals

The list of 182 prior Carnivals of Space is here

If you run a space/astronomy related blog, and would like to get more awareness, participate in the Carnival of Space. Every week, a different webmaster or blogger hosts the carnival, showcasing articles written on the topic of space. It’s a great way to get to know the community, and to help your writing reach a wider audience. If you’d like to be a host for the carnival, please drop me an email at [email protected].

February 7, 2011April 26, 2016 by Nancy Atkinson

A Galaxy With a Big “S” on Its Chest

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Can galaxy NGC 157 leap tall buildings in a single bound, stop a speeding bullet or bend steel in it’s bare hands? This relatively mild-mannered galaxy has a central sweep of stars that resembles a giant “S”, almost just like the comic book hero Superman’s symbol. The image was taken by the HAWK-I (High-Acuity Wide-field K-band Imager) on the Very Large Telescope in Chile. HAWK-I looks in infrared light, allowing us to peer through the gas and dust that normally obscures our view and see parts of NCG 157 that otherwise is hidden from our optical view.

Looking at this and other galaxies like it, astronomers can learn about star formation, as the same processes that are coalescing material and creating stars in NGC 157 also took place around 4.5 billion years ago in the Milky Way to form our own star, the Sun.

NGC 157 is faint — about magnitude 11, but can be seen bigger amateur telescopes. It is located within the constellation of Cetus (the Sea Monster).

For those interested in observing this object, see this post on WikiSky.

And just in case you don’t get the Superman references:

Source: ESO