Freedawn Scientia: Space

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Friday, 10 June 2016

In The Life of The ISS

In In The Life of The ISS – Question Time

This post is dedicated to our friend Mihaela from Facebook that recently asked us a question that is partially related to the International Space Station (ISS). The Question was…

How many sunrises can an astronaut see from an orbiting space station, if it orbits the Earth in 90 minutes, and why?

This is a brilliant question and thank you Mihaela for asking us to look into it for you. I will be going through two parts to answering this. The first part is the straight forward answer, we will then go through a little more information about the ISS with some visulisations, that will help see why the aforementioned occurs. I have also used the ISS as an example as this is the most commonly known space station (seriously, isn’t it pretty cool we have space stations just whipping above us as we speak), plus there are some great apps available that allow you to track the ISS.

The Short Answer…

The ISS takes 92 minutes to orbit the earth once. Where as somewhere on Earth takes 24 hours to complete a full rotation and we see one sun rise and one sunset.

As it takes approximately 92 minutes for the ISS to complete and orbit, this means that every 45 minutes or so they will witness a sunrise or a sunset as they effectively pass over the point that Earth would be having a sun rise or a sun set at that particular time.

This means, over the course of 24 hours (Earth’s full rotation) the ISS will observe between 15 and 16 sun rises and sunsets.

Now a little more information on the ISS

The space station is made of many pieces. The pieces were put together in space by astronauts. The space station’s orbit is about 220 miles above Earth. NASA uses the station to learn about living and working in space. These lessons will help NASA explore space.

Questions and Facts

How Old Is the Space Station?

The first piece of the International Space Station was launched in 1998. A Russian rocket launched that piece. After that, more pieces were added. Two years later, the station was ready for people. The first crew arrived on November 2, 2000. People have lived on the space station ever since. Over time more pieces have been added. NASA and its partners around the world finished the space station in 2011.

How Big Is the Space Station?

The space station is as big inside as a house with five bedrooms. It has two bathrooms, a gymnasium and a big bay window. Six people are able to live there. It weighs almost a million pounds. It is big enough to cover a football field including the end zones. It has science labs from the United States, Russia, Japan and Europe.

What Are the Parts of the Space Station?

The space station has many parts. The parts are called modules. The first modules had parts needed to make the space station work. Astronauts also lived in those modules. Modules called “nodes” connect parts of the station to each other. Labs on the space station let astronauts do research.

On the sides of the space station are solar arrays. These arrays collect energy from the sun. They turn sunlight into electricity. Robot arms are attached outside. The robot arms helped to build the space station. They also can move astronauts around outside and control science experiments.

Airlocks on the space station are like doors. Astronauts use them to go outside on spacewalks.

Docking ports are like doors, too. The ports allow visiting spacecraft to connect to the space station. New crews and visitors enter the station through the docking ports. Astronauts fly to the space station on the Russian Soyuz. The crew members use the ports to move supplies onto the station.

Why Is the Space Station Important?

The space station is a home in orbit. People have lived in space every day since the year 2000. The space station’s labs are where crew members do research. This research could not be done on Earth.

Scientists study what happens to people when they live in space. NASA has learned how to keep a spacecraft working for a long time. These lessons will be important in the future.

NASA has a plan to send humans deeper into space than ever before. The space station is one of the first steps. NASA will use lessons from the space station to get astronauts ready for the journey ahead.

Some Quick Facts about the ISS

1. It took an astounding 136 space flights on seven different types of launch vehicles to build it.

2. It flies at 4.791 miles per second (7.71 km/s). That’s fast enough to go to the Moon and back in about a day.

3. It weighs almost 1 million pounds including visiting spacecraft. Picture 120,000 gallons of milk in supermarket cartons in your mind.

4. It has 8 miles of wire just to connect the electrical power system. That will be enough to connect a hair dryer in Newark, New Jersey, to a power plug in New York City.

5. It has a complete surface area the size of a US football field, which actually makes it almost as large as the Tantive IV, the Corellian Corvette that carried Princess Leia.

6. It has more livable space than a 6-bedroom house.

7. It has two bathrooms, a gymnasium and a 360-degree bay window.

8. It’s been the spaceport for 89 Russian Soyuz spacecraft, 37 Space Shuttle missions, three SpaceX Dragons, four Japanese HTV cargo spacecraft, and four European ATV cargo spacecraft.

9. All its research experiments and spacecraft systems are housed in a bit more than one hundred telephone-booth sized racks.

10. The US solar array surface area on the is 38,400 sq. feet (.88 acre), which is large enough to cover 8 basketball courts

11. According to NASA, “there are 52 computers controlling the ISS.” Just for the US segment, there are “1.5 million lines of flight software code run on 44 computers communicating via 100 data networks transferring 400,000 signals.”

12. Its internal pressurized volume is 32,333 cubic feet, which is about the same of a Jumbo Boeing 747.

13. The ISS crews have eaten about 25,000 meals since 2000. That’s a staggering “seven tons of supplies per three astronauts for six months.” That’s 32,558 Big Macs.

14. 211 people from 15 countries have visited the ISS so far.

15. When it reaches the end of its life, some of the most modern Russian modules—like Nauka—will be reused to make a third space station to support interplanetary mission to Mars, the Moon and Saturn, serving as a launching and return point.

Some Questions Answered by the NASA Team

Do you believe in that the design of the ISS will cause a problem in case of a meteor shower? Why?

That’s a really good question. The space environment is a very harsh environment: there’s radiation and micrometeorite strikes, and other things in the environment that cause it to be very hazardous. So, one of the things that we’ve designed the space station for is to protect the astronauts against micrometeorite striking the outer shell of the space station. Now, in doing so, the basic design philosophy of the pressurized modules has been to develop an inner shell, which contains the pressurized interior of the space station, and then a layer of insulation around that inner shell, and then an outer armor plating, if you will, to the exterior. And what that does is protects against small pieces of debris that strike the station and can cause leaks. Now, for larger pieces of debris: they actually track them and have to actually move the space station out of the way of the larger pieces that could cause serious damage to the station.

What kind of contingency plan does the ISS have in case of an emergency? How long do life support systems on board last for the stranded astronauts? Is there such a thing as an emergency launch to the ISS using the current space shuttles?

Well, there are several redundant systems on the space station, which really enable the astronauts to survive for long periods of time without a space shuttle or a Russian re-supply ship coming to bring additional supplies. Now, in the event of an outright emergency, where the lives of the astronauts were threatened, they would have to evacuate the space station using the Soyuz module, but the life support systems themselves are designed to last for months at a time without a re-supply ship.

What would you say to date has been the greatest benefit to mankind from the space station, and what is its predicted benefits?

Well, I think it’s all a matter of judgment, but to me the greatest benefit of the space station is the international cooperation to date that we’ve had with over 16 different countries contributing to the International Space Station; countries that were at one time, enemies of each other, have now come together to do something that will benefit mankind. I think down the road the space station will bring great leaps in science, in medical fields, in the materials manufacturing fields, and it will also teach us a lot about long duration human space flight so that we can expand our civilization beyond Earth.

Why is the center truss section called S-Zero?

That’s actually a really good question, because the trusses are named for whether they’re on the starboard side or the port side; so you have S-Zero, S-One, P-One, S-Three, P-Three, P-Four, S-Four, P-Five, S-Five. Well, S-Zero being in the middle, I guess they couldn’t decide whether to call it S-Zero or P-Zero, and maybe they flipped a coin or whatever else and decided to call it S-Zero, but it’s actually in the center, it’s not on the starboard side or the port side, so it could have just as easily been named P-Zero.

Does the International Space Station have any hardware or machines that were specifically invented for it and cannot be found anywhere else? What are they?

Well, the International Space Station has lots of unique hardware elements that were designed specifically for the International Space Station. They also use off-the-shelf technology when possible; one instance of that is the cameras that they use on the space station for the interior of the space station are actually just off-the-shelf camcorders. But, some, there’s certainly a great amount of technology that was developed specifically for the International Space Station to function specifically in the space environment. I think one of the best examples of that is the Canadian robotic arm. The Canadian robotic arm was developed specifically for the International Space Station and fills the task of actually constructing the International Space Station, and it doesn’t even function in the Earth environment in the one-G conditions that we have here on Earth.

When will the International Space Station be completed?

Well also that’s a very interesting question. The core complete milestone that we are reaching for right now is due in the mid-2004 timeframe. Now, after we finish building what’s essentially the core of the International Space Station then we have a lot of additional options to add elements developed by international partners, and other additional features that we might want to add. The fact that the space station was designed the way it was allows us to once we get to the core complete milestone to expand it to provide lots of additional capabilities.

Which ISS docking port is being used by the Soyuz TM-34 spacecraft? Also, where on the station will Endeavour and Leonardo dock?

Well, the Soyuz module is nominally docked to the end of the Russian service module. Now, there are additional docking ports on the Russian functional cargo block, I’m sorry, on the bottom of the service module, where the Soyuz modules can be docked. And when they bring a second one up onto orbit in order to switch out the first one when they have to replace them, they actually have to move one of the Soyuz modules from the end of the service module to the bottom of the service module, and the second service module goes on to the end. The space shuttle, on the other hand, docks to the American side of the space station, to the Destiny laboratory. And the MPLM, Leonardo, in this case, is docked to Node-1, which was also built by an American company, Boeing.

Is it possible to give the times and locations of when the ISS passes over Central California?

Well, it’s actually possible to find out when the space station will be passing over your head no matter where you live, and there’s a website, it’s http://spaceflight.nasa.gov, and if you go that website, you can follow links and actually no matter what city you are in the country, you can find out when the space station will be traveling overhead.

With respect to the space station, why can’t we just shoot the trash off towards the sun instead of bringing it back to Earth?

Well, that’s actually a question that I used to wonder about when I was growing up, why didn’t we just put all the trash into the sun to save our garbage problems here on Earth. Unfortunately, it would take a lot of rocket power to get anything to the Sun, and so it’s sort of a limiting factor to be able to launch something out the sphere of influence of the Earth. Now, the trash on the International Space Station, not all of it is brought back to Earth. Some of it is placed in the Russian Progress modules, which are sent on a trajectory into the Earth’s atmosphere that burns it back up. So it’s not all brought back to Earth, just some of it in the MPLM modules.

After the completion of the ISS, how much will it contribute to the flight of humans to Mars, and return trips to the Moon?

Well, this kind of goes with the earlier question, about what the benefits of the International Space Station are. If we’re going to go to Mars, or spend long periods of time on the Moon, we have to learn what the effects of long term space flight is going to be on our astronauts. We don’t have a lot of information about what the space environment does to our astronauts, beyond, say six months. There are astronauts, particularly from Russia, who have spend more time than that in space, but very few, so we don’t have a large amount of data, and it’d be very risky to send astronauts to Mars, to spend say, a year and a half outside of the Earth environment, or more, without knowing exactly what the effects of the long term exposure to space would be. So, the International Space Station in addition to us just developing the technology to live in space for large amounts of time, it gives us the information that we need about how long astronauts can safely stay in space.

Is it possible to use a flywheel mechanism to produce power for the space station? Have there been any experiments using this technology to produce power in space?

Well, it’s actually not possible to use flywheels to generate power in the classical sense, but you can use flywheels to store power. So, you would have to use some other source to generate the power, but then to store it you could spin up flywheels and then use the kinetic energy from the flywheels to actually store energy. But because the power requirements of the space station are so large, it’s a lot more practical for us to use batteries to store power on the station. So, the answer to the question is no, we don’t use flywheels to store power.

How many different civilian contracting companies, on average, participate in the building of one of our space station modules?

Well, most of the American space station modules were developed and built by the prime contractor for the space station, which is Boeing. Now, Boeing has dozens, if not hundreds of subcontractors that it uses to build everything from the smallest screw used on the space station to a complex computer, or a solar array. So, there’s one prime contractor, but dozens, if not hundreds of subcontractors.

When the space station needs to make an orbital adjustment, do the occupants of the space station feel the movement of the adjustment?

Well, the reason why I think that’s such a good question is because it really highlights one of the most fundamental laws of physics we have, and there are basically three laws of physics that Isaac Newton postulated hundreds of years ago, and one of those laws it that force equals mass times acceleration. Now, the key thing about these laws is that no matter where you are in the universe, they are true. So whether you’re on Earth or whether you’re in space, these laws are true. Now, this particular law, force equals mass plus acceleration, when you press the gas pedal in your car, your car accelerates, you go from say, 55 miles an hour to 60 miles an hour. That acceleration is what causes you to feel that force. Now, in space, when they fire the thrusters on the space station, the space station also accelerates. But the acceleration is generally very, very small. So sometimes the astronauts might not notice the space station is accelerating. But that also brings in another interesting point, in what they might see, since the astronauts are floating free with respect to the space station, that when the space station fires it thrusters, the space station would move, and the astronauts, not touching one of the surfaces, would not move, so they would see the space station actually moving around them.

During a 24 hour period, how many times does the ISS orbit the Earth?

Well, the space station orbits Earth about every 90 minutes, so that means in a 24 hour day, the space station orbits approximately 16 times.

In operating, maintaining, and troubleshooting problems on the ISS, how involved does the ISS crew get versus the control center team?

Well, that’s a very good question. NASA has an entire army of people supporting the operations of the International Space Station. Of course, the astronauts are often the first line of defense, and especially in emergency situations, they have to make quick, critical decisions that will allow everybody to be safe. Now, the mission control people are a huge part of supporting that and laying out those plans for the emergency situations. But, in the event that something goes wrong on the station, NASA has the ability to go back to the people who actually designed the hardware and ask them what they think about the problem, and if it’s something they might have seen before in ground testing. So it’s a collaborative effort across all of the different countries that make up the hardware that we use on the International Space Station.

On certain days we are able to visualize the space station as it seems to streak across the sky. How fast is the ISS traveling?

Well, in order for the space station to stay in orbit, it has to travel at seven kilometers per second, which the equivalent in miles per hour, is around 15,500 miles per hour. So that’s pretty fast!

I hope you enjoyed this post and Mihaela, I hope this answered your question and then some more 🙂 thank you so so much for the question. If you or anyone else has any more questions please let us know on our Scientia facebook page or use the forums on Scientia to start your own thread.

– Credit and Resource –

NASA

In The Life of The ISS

Saturday, 28 May 2016

Link Between Primordial Black Holes and Dark Matter

Scientist suggests possible link between primordial black holes and dark matter

primordial black holes, dark matter, NASA, Spitzer Space Telescope, Ursa Major, universe, space, gravity, massive exotic particle, X-ray background glows,

Left: This image from NASA’s Spitzer Space Telescope shows an infrared view of a sky area in the constellation Ursa Major. Right: After masking out all known stars, galaxies and artifacts and enhancing what’s left, an irregular background glow appears. This is the cosmic infrared background (CIB); lighter colors indicate brighter areas. The CIB glow is more irregular than can be explained by distant unresolved galaxies, and this excess structure is thought to be light emitted when the universe was less than a billion years old. Scientists say it likely originated from the first luminous objects to form in the universe, which includes both the first stars and black holes. Credit: NASA/JPL-Caltech/A. Kashlinsky (Goddard)

Scientia — Dark matter is a mysterious substance composing most of the material universe, now widely thought to be some form of massive exotic particle. An intriguing alternative view is that dark matter is made of black holes formed during the first second of our universe’s existence, known as primordial black holes. Now a scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, suggests that this interpretation aligns with our knowledge of cosmic infrared and X-ray background glows and may explain the unexpectedly high masses of merging black holes detected last year.

“This study is an effort to bring together a broad set of ideas and observations to test how well they fit, and the fit is surprisingly good,” said Alexander Kashlinsky, an astrophysicist at NASA Goddard. “If this is correct, then all galaxies, including our own, are embedded within a vast sphere of black holes each about 30 times the sun’s mass.”

In 2005, Kashlinsky led a team of astronomers using NASA’s Spitzer Space Telescope to explore the background glow of infrared light in one part of the sky. The researchers reported excessive patchiness in the glow and concluded it was likely caused by the aggregate light of the first sources to illuminate the universe more than 13 billion years ago. Follow-up studies confirmed that this cosmic infrared background (CIB) showed similar unexpected structure in other parts of the sky.

In 2013, another study compared how the cosmic X-ray background (CXB) detected by NASA’s Chandra X-ray Observatory compared to the CIB in the same area of the sky. The first stars emitted mainly optical and ultraviolet light, which today is stretched into the infrared by the expansion of space, so they should not contribute significantly to the CXB.

Yet the irregular glow of low-energy X-rays in the CXB matched the patchiness of the CIB quite well. The only object we know of that can be sufficiently luminous across this wide an energy range is a black hole. The research team concluded that primordial black holes must have been abundant among the earliest stars, making up at least about one out of every five of the sources contributing to the CIB.

The nature of dark matter remains one of the most important unresolved issues in astrophysics. Scientists currently favor theoretical models that explain dark matter as an exotic massive particle, but so far searches have failed to turn up evidence these hypothetical particles actually exist. NASA is currently investigating this issue as part of its Alpha Magnetic Spectrometer and Fermi Gamma-ray Space Telescope missions.

“These studies are providing increasingly sensitive results, slowly shrinking the box of parameters where dark matter particles can hide,” Kashlinsky said. “The failure to find them has led to renewed interest in studying how well primordial black holes—black holes formed in the universe’s first fraction of a second—could work as dark matter.”

Physicists have outlined several ways in which the hot, rapidly expanding universe could produce primordial black holes in the first thousandths of a second after the Big Bang. The older the universe is when these mechanisms take hold, the larger the black holes can be. And because the window for creating them lasts only a tiny fraction of the first second, scientists expect primordial black holes would exhibit a narrow range of masses.

Primordial black holes, if they exist, could be similar to the merging black holes detected by the LIGO team in 2014. This computer simulation shows in slow motion what this merger would have looked like up close. The ring around the black holes, called an Einstein ring, arises from all the stars in a small region directly behind the holes whose light is distorted by gravitational lensing. The gravitational waves detected by LIGO are not shown in this video, although their effects can be seen in the Einstein ring. Gravitational waves traveling out behind the black holes disturb stellar images comprising the Einstein ring, causing them to slosh around in the ring even long after the merger is complete. Gravitational waves traveling in other directions cause weaker, shorter-lived sloshing everywhere outside the Einstein ring. If played back in real time, the movie would last about a third of a second. Credit: SXS Lensing

On Sept. 14, gravitational waves produced by a pair of merging black holes 1.3 billion light-years away were captured by the Laser Interferometer Gravitational-Wave Observatory (LIGO) facilities in Hanford, Washington, and Livingston, Louisiana. This event marked the first-ever detection of gravitational waves as well as the first direct detection of black holes. The signal provided LIGO scientists with information about the masses of the individual black holes, which were 29 and 36 times the sun’s mass, plus or minus about four solar masses. These values were both unexpectedly large and surprisingly similar.

“Depending on the mechanism at work, primordial black holes could have properties very similar to what LIGO detected,” Kashlinsky explained. “If we assume this is the case, that LIGO caught a merger of black holes formed in the early universe, we can look at the consequences this has on our understanding of how the cosmos ultimately evolved.”

In his new paper, published May 24 in The Astrophysical Journal Letters, Kashlinsky analyzes what might have happened if dark matter consisted of a population of black holes similar to those detected by LIGO. The black holes distort the distribution of mass in the early universe, adding a small fluctuation that has consequences hundreds of millions of years later, when the first stars begin to form.

For much of the universe’s first 500 million years, normal matter remained too hot to coalesce into the first stars. Dark matter was unaffected by the high temperature because, whatever its nature, it primarily interacts through gravity. Aggregating by mutual attraction, dark matter first collapsed into clumps called minihaloes, which provided a gravitational seed enabling normal matter to accumulate. Hot gas collapsed toward the minihaloes, resulting in pockets of gas dense enough to further collapse on their own into the first stars. Kashlinsky shows that if black holes play the part of dark matter, this process occurs more rapidly and easily produces the lumpiness of the CIB detected in Spitzer data even if only a small fraction of minihaloes manage to produce stars.

As cosmic gas fell into the minihaloes, their constituent black holes would naturally capture some of it too. Matter falling toward a black hole heats up and ultimately produces X-rays. Together, infrared light from the first stars and X-rays from gas falling into dark matter black holes can account for the observed agreement between the patchiness of the CIB and the CXB.

Occasionally, some primordial black holes will pass close enough to be gravitationally captured into binary systems. The black holes in each of these binaries will, over eons, emit gravitational radiation, lose orbital energy and spiral inward, ultimately merging into a larger black hole like the event LIGO observed.

“Future LIGO observing runs will tell us much more about the universe’s population of black holes, and it won’t be long before we’ll know if the scenario I outline is either supported or ruled out,” Kashlinsky said.

Kashlinsky leads science team centered at Goddard that is participating in the European Space Agency’s Euclid mission, which is currently scheduled to launch in 2020. The project, named LIBRAE, will enable the observatory to probe source populations in the CIB with high precision and determine what portion was produced by black holes.

– Credit and Resource –

More information: A. Kashlinsky. LIGO GRAVITATIONAL WAVE DETECTION, PRIMORDIAL BLACK HOLES, AND THE NEAR-IR COSMIC INFRARED BACKGROUND ANISOTROPIES, The Astrophysical Journal (2016). DOI: 10.3847/2041-8205/823/2/L25 , On Arxiv: arxiv.org/abs/1605.04023

Journal reference: Astrophysical Journal Letters, Astrophysical Journal, arXiv

Provided by: NASA

Link Between Primordial Black Holes and Dark Matter

Juno Spacecraft Crosses Jupiter/Sun Gravity Boundary

NASA’s Juno Spacecraft Crosses Jupiter/Sun Gravitational Boundary

Scientia — Since its launch five years ago, there have been three forces tugging at NASA’s Juno spacecraft as it speeds through the solar system. The sun, Earth and Jupiter have all been influential — a gravitational trifecta of sorts. At times, Earth was close enough to be the frontrunner. More recently, the sun has had the most clout when it comes to Juno’s trajectory. Today, it can be reported that Jupiter is now in the gravitational driver’s seat, and the basketball court-sized spacecraft is not looking back.

Juno Spacecraft, Juno, spacecraft, space, NASA, solar system, plants, Jupiter, gravity, Sun, gravitational forces

This artist’s rendering shows NASA’s Juno spacecraft making one of its close passes over Jupiter.
Credits: NASA/JPL-Caltech

“Today the gravitational influence of Jupiter is neck and neck with that of the sun,” said Rick Nybakken, Juno project manager at NASA’s Jet Propulsion Laboratory in Pasadena, California. “As of tomorrow, and for the rest of the mission, we project Jupiter’s gravity will dominate as the trajectory-perturbing effects by other celestial bodies are reduced to insignificant roles.”

Juno was launched on Aug. 5, 2011. On July 4 of this year, it will perform a Jupiter orbit insertion maneuver — a 35-minute burn of its main engine, which will impart a mean change in velocity of 1,212 mph (542 meters per second) on the spacecraft. Once in orbit, the spacecraft will circle the Jovian world 37 times, skimming to within 3,100 miles (5,000 kilometers) above the planet’s cloud tops. During the flybys, Juno will probe beneath the obscuring cloud cover of Jupiter and study its auroras to learn more about the planet’s origins, structure, atmosphere and magnetosphere.

Juno’s name comes from Greek and Roman mythology. The mythical god Jupiter drew a veil of clouds around himself to hide his mischief, and his wife — the goddess Juno — was able to peer through the clouds and reveal Jupiter’s true nature.

NASA’s Jet Propulsion Laboratory, Pasadena, California, manages the Juno mission for the principal investigator, Scott Bolton, of Southwest Research Institute in San Antonio. Juno is part of NASA’s New Frontiers Program, which is managed at NASA’s Marshall Space Flight Center in Huntsville, Alabama, for NASA’s Science Mission Directorate. Lockheed Martin Space Systems, Denver, built the spacecraft. The California Institute of Technology in Pasadena manages JPL for NASA.

– Credit and Resource –

NASA

Juno Spacecraft Crosses Jupiter/Sun Gravity Boundary

Life on Ceres

Life on Ceres? Mysterious changes in the bright spots still baffle scientists

Scientia –Bright spots on the dwarf planet Ceres continue to puzzle researchers. When recently a team of astronomers led by Paolo Molaro of the Trieste Astronomical Observatory in Italy, conducted observations of these features, they found out something unexpected. The scientists were surprised to detect that the spots brighten during the day and also show other variations. This variability still remains a mystery.

The bright features have been discovered by NASA’s Dawn spacecraft which is orbiting this dwarf planet, constantly delivering substantial information about it. These spots reflect far more light than their much darker surroundings. The composition of these features is discussed as the scientists debate if they are made of water ice, of evaporated salts, or something else.

Molaro and his colleagues studied the spots on Ceres in July and August 2015, using the High Accuracy Radial velocity Planet Searcher (HARPS), as was reported by the European Southern Observatory (ESO) earlier this year. This instrument, mounted on ESO’s 3.6m telescope at La Silla Observatory in Chile, enables measurements of radial velocities with the highest accuracy currently available.

By utilizing HARPS, the researchers found out unexpected changes in the mysterious bright spots. However, at the beginning they thought that it was an instrumental problem. But after double checking, they had to conclude that the radial velocity anomalies were likely real. Then the team noticed that they were connected to periods of time when the bright spots in the Occator crater were visible from the Earth. So the scientists made an association between them.

However, these detected variations still continue to perplex the astronomers as they haven’t found a plausible explanation for their occurrence.

“We know nothing about these changes, really. And this increases the mystery of these spots,” Molaro told Astrowatch.net.

One of the proposed hypotheses is that the observed changes could be triggered by the presence of volatile substances that evaporate due to solar radiation. When the spots are on the side illuminated by the sun they form plumes that reflect sunlight very effectively. The scientists suggest that these plumes then evaporate quickly, lose reflectivity and produce the observed changes.

“It is already well known that a lot of water hides beneath the surface of Ceres, so water ice or clathrates hydrates are the most natural hypotheses. But a proper answer will be hopefully provided by scientists working in the Dawn team in the coming months,” Molaro said.

He noted that the indication of variability needs to be confirmed by direct imaging of Occator’s bright spot at the highest available spatial resolution.

“This kind of measurements are underway. I would say that the detection of a variability improves our ignorance rather than our understanding of this planetary body,” Molaro revealed.

The team is currently applying for further observations by the end of this year to repeat in a more systematical way what they have done in their pilot project. An important aspect of their work is to have shown a new way to study Ceres from ground, which could turn out to be useful even after the end of the Dawn mission. However by now, they are eager to see the results from the Dawn spacecraft in the next months.

If the team’s theory is confirmed, Ceres would seem to be internally active. While this dwarf planet is known to be rich in water, it is unclear whether this is related to the bright spots. It is also still debated if Ceres due to its vast reservoir of water, could be a suitable place to host microbial life.

“Life as we know it on Earth needs liquid water, biogenic elements and a stable source of energy. Is Ceres a good place to have these things simultaneously and for a substantial amount of time, like billions of years? Nobody knows at the moment,” Molaro concluded.

A little about Ceres

-Discovered: January 1,1801 by Giuseppe Piazzi of Italy (first asteroid/dwarf planet discovered)

-Size: 975 by 909 kilometers (606 by 565 miles)

-Shape: Spheroid

-Rotation: Once every 9 hours, 4.5 minutes

The object is known by astronomers as “1 Ceres” because it was the very first minor planet discovered. As big across as Texas, Ceres’ nearly spherical body has a differentiated interior – meaning that, like Earth, it has denser material at the core and lighter minerals near the surface. Astronomers believe that water ice may be buried under Ceres’ crust because its density is less than that of the Earth’s crust, and because the dust-covered surface bears spectral evidence of water-bearing minerals. Ceres could even boast frost-covered polar caps.

Astronomers estimate that if Ceres were composed of 25 percent water, it may have more water than all the fresh water on Earth. Ceres’ water, unlike Earth’s, is expected to be in the form of water ice located in its mantle.

– Credit and Resource –

NASA

Life on Ceres

Wednesday, 9 December 2015

Visualization of Space Environment at Pluto

NASA Releases New Visualization of Space Environment at Pluto

This video shows a simulation of the space environment all the way out to Pluto in the months surrounding New Horizons’ July 2015 flyby. At the time, scientists at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, worked with the New Horizons team to test how well their models—and other models contributed by scientists around the world—predicted the space environment at Pluto. Understanding the environment through which our spacecraft travel can ultimately help protect them from radiation and other potentially damaging effects. Visualizers at Goddard recently updated the movie of the model, creating this new release.

Credits: NASA’s Goddard Space Flight Center Scientific Visualization Studio, the Space Weather Research Center (SWRC) and the Community-Coordinated Modeling Center (CCMC), Enlil and Dusan Odstrcil (GMU).
Download this video in HD formats from NASA Goddard’s Scientific Visualization Studio

Though the vacuum of space is about a thousand times emptier than a laboratory vacuum, it’s still not completely empty. The sun releases a constant stream of particles called the solar wind—as well as occasional denser clouds of particles known as coronal mass ejections, or CMEs—both containing embedded magnetic fields. The density, speed, and temperature of these particles, as well as the direction and strength of the embedded magnetic fields, make up the space environment.

To map the space environment at Pluto, scientists combined the predictions of several models—and looked at events that had long since passed Earth.

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This artist’s concept depicts the New Horizons spacecraft during its July 2015 encounter with Pluto and one of the dwarf planet’s moons, Charon.
Credits: Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute

“We set the simulation to start in January of 2015, because the particles passing Pluto in July 2015 took some six months to make the journey from the sun,” said Dusan Odstrcil, a space weather scientist at Goddard who created the Enlil model. The Enlil model, named for the Sumerian god of the wind, is one of the primary models used to simulate the space environment near Earth and is the basis for the New Horizons simulation.

The new, combined model tracks CMEs longer than ever before. Because particles must travel for many months before reaching Pluto, the CMEs eventually spread out and merge with other CMEs and the solar wind to form larger clouds of particles and magnetic field. These combined clouds stretch out as they travel away from the sun, forming thin ring shapes by the time they reach Pluto—quite different from the typical balloon shape of CMEs seen here at Earth.

– Credit and Resource –

NASA

Visualization of Space Environment at Pluto

Thursday, 24 September 2015

What is Dark Matter and Dark Energy?

Dark Energy and Dark Matter

In the early 1990s, one thing was fairly certain about the expansion of the Universe. It might have enough energy density to stop its expansion and recollapse, it might have so little energy density that it would never stop expanding, but gravity was certain to slow the expansion as time went on. Granted, the slowing had not been observed, but, theoretically, the Universe had to slow. The Universe is full of matter and the attractive force of gravity pulls all matter together. Then came 1998 and the Hubble Space Telescope (HST) observations of very distant supernovae that showed that, a long time ago, the Universe was actually expanding more slowly than it is today. So the expansion of the Universe has not been slowing due to gravity, as everyone thought, it has been accelerating. No one expected this, no one knew how to explain it. But something was causing it.

Eventually theorists came up with three sorts of explanations. Maybe it was a result of a long-discarded version of Einstein’s theory of gravity, one that contained what was called a “cosmological constant.” Maybe there was some strange kind of energy-fluid that filled space. Maybe there is something wrong with Einstein’s theory of gravity and a new theory could include some kind of field that creates this cosmic acceleration. Theorists still don’t know what the correct explanation is, but they have given the solution a name. It is called dark energy.

What Is Dark Energy?

More is unknown than is known. We know how much dark energy there is because we know how it affects the Universe’s expansion. Other than that, it is a complete mystery. But it is an important mystery. It turns out that roughly 68% of the Universe is dark energy. Dark matter makes up about 27%. The rest – everything on Earth, everything ever observed with all of our instruments, all normal matter – adds up to less than 5% of the Universe. Come to think of it, maybe it shouldn’t be called “normal” matter at all, since it is such a small fraction of the Universe.

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This diagram reveals changes in the rate of expansion since the universe’s birth 15 billion years ago. The more shallow the curve, the faster the rate of expansion. The curve changes noticeably about 7.5 billion years ago, when objects in the universe began flying apart as a faster rate. Astronomers theorize that the faster expansion rate is due to a mysterious, dark force that is pulling galaxies apart.
NASA/STSci/Ann Feild

One explanation for dark energy is that it is a property of space. Albert Einstein was the first person to realize that empty space is not nothing. Space has amazing properties, many of which are just beginning to be understood. The first property that Einstein discovered is that it is possible for more space to come into existence. Then one version of Einstein’s gravity theory, the version that contains a cosmological constant, makes a second prediction: “empty space” can possess its own energy. Because this energy is a property of space itself, it would not be diluted as space expands. As more space comes into existence, more of this energy-of-space would appear. As a result, this form of energy would cause the Universe to expand faster and faster. Unfortunately, no one understands why the cosmological constant should even be there, much less why it would have exactly the right value to cause the observed acceleration of the Universe.

Another explanation for how space acquires energy comes from the quantum theory of matter. In this theory, “empty space” is actually full of temporary (“virtual”) particles that continually form and then disappear. But when physicists tried to calculate how much energy this would give empty space, the answer came out wrong – wrong by a lot. The number came out 10120 times too big. That’s a 1 with 120 zeros after it. It’s hard to get an answer that bad. So the mystery continues.

Another explanation for dark energy is that it is a new kind of dynamical energy fluid or field, something that fills all of space but something whose effect on the expansion of the Universe is the opposite of that of matter and normal energy. Some theorists have named this “quintessence,” after the fifth element of the Greek philosophers. But, if quintessence is the answer, we still don’t know what it is like, what it interacts with, or why it exists. So the mystery continues.

A last possibility is that Einstein’s theory of gravity is not correct. That would not only affect the expansion of the Universe, but it would also affect the way that normal matter in galaxies and clusters of galaxies behaved. This fact would provide a way to decide if the solution to the dark energy problem is a new gravity theory or not: we could observe how galaxies come together in clusters. But if it does turn out that a new theory of gravity is needed, what kind of theory would it be? How could it correctly describe the motion of the bodies in the Solar System, as Einstein’s theory is known to do, and still give us the different prediction for the Universe that we need? There are candidate theories, but none are compelling. So the mystery continues.

The thing that is needed to decide between dark energy possibilities – a property of space, a new dynamic fluid, or a new theory of gravity – is more data, better data.

What is Dark Matter?

By fitting a theoretical model of the composition of the Universe to the combined set of cosmological observations, scientists have come up with the composition that we described above, ~68% dark energy, ~27% dark matter, ~5% normal matter. What is dark matter?

We are much more certain what dark matter is not than we are what it is. First, it is dark, meaning that it is not in the form of stars and planets that we see. Observations show that there is far too little visible matter in the Universe to make up the 27% required by the observations. Second, it is not in the form of dark clouds of normal matter, matter made up of particles called baryons. We know this because we would be able to detect baryonic clouds by their absorption of radiation passing through them. Third, dark matter is not antimatter, because we do not see the unique gamma rays that are produced when antimatter annihilates with matter. Finally, we can rule out large galaxy-sized black holes on the basis of how many gravitational lenses we see. High concentrations of matter bend light passing near them from objects further away, but we do not see enough lensing events to suggest that such objects to make up the required 25% dark matter contribution.

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One of the most complicated and dramatic collisions between galaxy clusters ever seen is captured in this new composite image of Abell 2744. The blue shows a map of the total mass concentration (mostly dark matter).

However, at this point, there are still a few dark matter possibilities that are viable. Baryonic matter could still make up the dark matter if it were all tied up in brown dwarfs or in small, dense chunks of heavy elements. These possibilities are known as massive compact halo objects, or “MACHOs”. But the most common view is that dark matter is not baryonic at all, but that it is made up of other, more exotic particles like axions or WIMPS (Weakly Interacting Massive Particles)

What is Dark Matter and Dark Energy?

Friday, 18 September 2015

Watch Rocket Fly into Space with On-board Camera

It’s a video that will make your head spin: Captured from the outside of an unmanned scientific rocket, the German Aerospace Center has released stunning new footage of a seven-minute trip into space and back.

The video was released Friday, about a month after the late June launch. What’s interesting about the event is not so much its mission, but the video itself. So far, there has been little footage of such expeditions into space, especially in HD quality.

The rocket, called Mapheus5, was launched in Sweden and was supposed to test the reaction of a variety of materials in weightlessness. Traveling with 6.5 times the speed of sound, the rocket reached space within seconds of its launch. Watching the video, you will notice that the rocket rapidly spins at first, but becomes stable once it reaches about 62 miles above earth. For six minutes, weightlessness sets in, which enables the scientists to conduct their experiments.

“The difference between spinning and stability is crucial in order to understand why scientific rockets are usually equipped with cameras. If a rocket doesn’t stop spinning, an unwanted gravity will be created within the flying object,” Ulrich Walter, a former astronaut and current professor for space technology, told The Washington Post.

Pretty much all nations with space programs use rockets as a cheaper alternative to pursuing research on the International Space Station. “Using rockets is a relatively easy way to experiment with a variety of objects under the conditions of weightlessness,” Walter said.

And judging by the German video, it’s not only a less costly — but also a beautiful — trip into space.

Rocket launch into space with an on-board camera attached – !!WARNING – please turn your speakers down slightly!!

Captured from the outside of an unmanned scientific rocket, the German Aerospace Center has released stunning new footage of a minutes-long trip into the universe, and back down to Earth. (DLR)

Watch Rocket Fly into Space with On-board Camera

Monday, 14 September 2015

New Green Propellants Complete Milestones

Scientia — To stay in the proper orbit, many satellites have thrusters–small rocket engines–that fire to change altitude or orientation in space. On Earth where gravity dominates, 5 pounds of thrust, equivalent to 22 Newtons of force, may seem small, but in space, it doesn’t take much thrust to move a large spacecraft.

Currently, most satellite thrusters are powered by hydrazine, a toxic and corrosive fuel that is dangerous to handle and store. In a quest to replace hydrazine with a more environmentally friendly fuel, NASA is testing thrusters propelled by green propellants that can provide better performance than hydrazine without the toxicity. These propellants could help lower costs by eliminating infrastructure needed for handling toxic fuels and reducing processing time–making it less expensive and safer and easier to launch both commercial and NASA spacecraft.

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This image reveals a temperature profile of a 22 Newton thruster using the green propellant LMP-103S during a 10-second pulsing test that ratchets the temperature upward. Using this data, engineers can determine how chemical reactions cause heat to flow around to the thruster over time.
Credits: NASA/MSFC/Christopher Burnside

“When you consider all of the satellites in orbit today that do everything from observing Earth and monitoring weather to peering deep into our universe to answer questions about its origins, it’s easy to see that using green propellants will make a big difference in increased mission performance at a reduced cost while keeping both the environment and our workforce safe from contamination,” said Steve Jurczyk, NASA’s associate administrator for the Space Technology Mission Directorate (STMD) at NASA Headquarters in Washington. “NASA has a rich history of ensuring our technology and scientific prowess has a benefit to life on Earth, and green propellant will help ensure that NASA continues to be a steward of this planet.”

NASA recently completed several hot-fire tests with thrusters powered by two different green propellants with the potential to replace hydrazine. Both are ionic liquid-based blends that are less toxic and less flammable than hydrazine, which makes them easier and less costly to store, to handle and to fuel up spacecraft before launch. Additionally, the new propellants offer higher performance, delivering more thrust for a given quantity of propellant than hydrazine.

NASA engineers monitor temperature data on the left computer screen as a thruster fueled with the green propellant LMP-103S viewed on the right computer screen is fired at NASA’s Marshall Space Flight Center in Huntsville, Alabama.
Credits: NASA/MSFC/Fred Deaton

One of the green propellants is a hydroxylammonium nitrate-based propellant known as AF-M315E. It was developed by the Air Force Research Laboratory at Edwards Air Force Base in California. This propellant will be demonstrated on a small satellite on NASA’s Green Propellant Infusion Mission (GPIM). During the GPIM flight, the smallsat will fire thrusters powered by AF-M315E to conduct maneuvers to change the satellite’s altitude and orientation. GPIM recently passed a major milestone with the delivery of the propellant’s propulsion subsystem built by Aerojet Rocketdyne in Redmond, Washington, to the mission’s prime contractor, Ball Aerospace & Technologies Corp. in Boulder, Colorado, for integration into the spacecraft. For this project, the GPIM team tested two different sized thrusters (1 and 22 Newton) with AF-M315E. Five of the 1-Newton thrusters will fly on GPIM.

“With GPIM’s flight scheduled to launch next year, NASA and the aerospace industry have taken positive steps to demonstrate use of a propellant that will reduce satellite fueling hazards and save time and money during launch campaigns,” said Tim Smith, GPIM mission manager for NASA’s Technology Demonstration Missions at Marshall. GPIM is managed by STMD’s Technology Demonstration Missions Program Office at Marshall.

The other green propellant is a fuel called LMP-103S, which is based on the oxidizer ammonium dinitramide produced by Eurenco Bofors in Karlskoga, Sweden. A team at NASA’s Marshall Space Flight Center in Huntsville, Alabama, recently completed tests with both 5 Newton and 22 Newton thruster built by ECAPS and powered by LMP-103S. Engineers fired the 22 Newton thruster 35 times under varying conditions and monitored results with infrared cameras. Orbital ATK, Inc. assisted NASA with these tests.

Large and small thrusters are used to propel satellites in space. NASA engineers conducted the first tests with a 22 Newton (5-pound) thruster fueled with the green propellant LMP-103S. Engineer Chris Burnside examines a smaller 5 Newton (1-pound) thruster that also was tested at NASA’s Marshall Space Flight Center in Huntsville, Alabama.
Credits: NASA/MSFC/Fred Deaton

“We conducted the first NASA tests with 22 Newton thrusters with this propellant in the United States,” said Christopher Burnside, lead engineer for testing the LMP-103S propellant. “They performed quite well, providing performance at comparable levels to today’s hydrazine thrusters. It’s always great to put thrusters through the paces in an environment that simulates operational conditions.”

To guide future investments, NASA is leading the development of a green propellant roadmap along with other government agencies, industry and academic leaders who recently shared their collective experiences during a technical interchange meeting at Marshall.

“I like the analogy of relating thrusters and propellant systems to aircraft,” said Charles Pierce, manager of Marshall’s Spacecraft Propulsion Systems Branch, which recently completed the tests with LMP-103S. “One aircraft doesn’t meet every need. Some high performance aircraft need to fly fast while other larger aircraft need to conserve fuel and fly slowly. Some carry passengers while others carry only cargo. Likewise, NASA needs to have flexibility in the types of thrusters and propellant systems it has to meet a variety of mission needs. One type of propellant might work best for one type of mission while another is better suited for a different mission. It’s important that we have choices as we go green.”

– Credit and Resource –

Tracy McMahan

NASA Marshall Space Flight Center

256-544-0034

tracy.mcmahan@nasa.gov

Last Updated: Sep. 14, 2015

Editor: Lee Mohon

New Green Propellants Complete Milestones