NASA Messenger extends its mission life using Helium

Now orbiting the planet Mercury after over ten years in space, NASA's MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft is still functioning better than expected.

Its mission will soon come to an end though, it's running out of fuel and is scheduled to crash into the planet in March.

However, mission control have come up with a novel plan that will use the helium used to pressurize the unmanned probe's engine to give it another month of life.

According to the MESSENGER team, fuel is usually the last problem that a robotic exploration team worry about because there are so many other things that can go wrong long before it runs out.

That being said, the fuel is the single most important consumable aboard an orbiter mission because it not only allows the spacecraft to maintain the correct attitude and keep its antennae pointed at Earth, it also lets it use the main engine to boost its orbit against atmospheric drag, which decays the orbit.

The upshot is that when the propellant runs out, the spacecraft starts to tumble and spirals in to burn up in the atmosphere or, in MESSENGER's case, crash into the surface at hypersonic speed.



So normally when the fuel runs out, that's it, but NASA reasoned that MESSENGER's liquid-fuel rocket engine design meant there was still a bit of thrust left even after all the propellant was expended.

The MESSENGER's engine is pressure fed, which means that it uses helium from a separate tank to push the fuel and oxidizer into the engine's combustion chamber.

Since the helium needs to work against the force of the rocket's combustion, it's under considerable pressure, and when the fuel is gone, there will be some helium left in the pressure tank.

The idea is to use the helium as a cold propellant. In other word's where the rocket engine gets its thrust by burning fuel, the helium pushes the spacecraft by simple gas pressure like a toy balloon when the open neck is let go.

Unfortunately, this is the first time a pressurant has been as an improvised thruster and MESSENGER's engine is a bit more complicated than a balloon.

According to MESSENGER Mission Systems Engineer Dan O’Shaughnessy, of the Johns Hopkins University Applied Physics Laboratory (APL), the pressure in the helium tank isn't much compared to a firing engine.

In addition, the gas passes through a number of reduction valves and nozzles that have to be taken into account, and helium is the second lightest of gases, so it doesn't provide much in the way of thrust.

If these problems can be overcome, NASA estimates that it will give MESSENGER another month of active life before impact on Mercury. MESSENGER's current closest approach to Mercury is 25 km (15 mi).

If a scheduled course correction using the helium is successful, this will rise to 80 km (50 mi). This will allow the orbiter to carry out additional low altitude observations, including collecting a new set of high-resolution images.

"During the additional period of operations, up to four weeks, MESSENGER will measure variations in Mercury’s internal magnetic field at shorter horizontal scales than ever before, scales comparable to the anticipated periapsis altitude between 7 km (4 mi) and 15 km (9 mi) above the planetary surface," says APL’s Haje Korth, the instrument scientist for the spacecraft's magnetometer.

"Combining these observations with those obtained earlier in the mission at slightly higher altitudes will allow the depths of the sources of these variations to be determined. In addition, observations by MESSENGER’s Neutron Spectrometer at the lowest altitudes of the mission will allow water ice deposits to be spatially resolved within individual impact craters at high northern latitudes."

Built and operated by John Hopkins University for NASA, the MESSENGER spacecraft was launched from Cape Canaveral on August 3, 2004 as the first mission aimed to place an orbiter around the innermost planet Mercury. 

Supernova iPTF13bvn: First evidence of a hydrogen-deficient supernova progenitor

An artist’s conception of a binary progenitor system of the supernova iPTF13bvn. 

Larger diameter but smaller mass (4 times mass of the Sun) helium star shown on the left is to explode. 

The companion star shown on the right is a hydrogen rich star and 30 times mass of the Sun. 

Credit: Kavli Institute for the Physics and Mathematics of the Universe

A group of researchers led by Melina Bersten of Kavli IPMU recently presented a model that provides the first characterization of the progenitor for a hydrogen-deficient supernova.

Their model predicts that a bright hot star, which is the binary companion to an exploding object, remains after the explosion.

To verify their theory, the group secured observation time with the Hubble Space Telescope (HST) to search for such a remaining star.

Their findings, which are reported in the October 2014 issue of The Astronomical Journal, have important implications for the evolution of massive stars.

For years astronomers have searched for the elusive progenitors of hydrogen-deficient stellar explosions without success.

However, this changed in June 2013 with the appearance of supernova iPTF13bvn and the subsequent detection of an object at the same location in archival images obtained before the explosion using the HST.

The interpretation of the observed object is controversial. The team led by Bersten presented a self-consistent picture using models of supernova brightness and progenitor evolution.

In their picture, the more massive star in a binary system explodes after transferring mass to its companion.

One of the challenges in astrophysics is identifying which star produces which supernova. This is particularly problematic for supernovae without hydrogen, which are called Types Ib or Ic, because the progenitors have yet to be detected directly.

However, the ultimate question is: "How do progenitor stars remove their hydrogen-rich envelopes during their evolution?"

Two competing mechanisms have been proposed. One hypothesizes that a strong wind produced by a very massive star blows the outer hydrogen layers, while the other suggests that a gravitationally bound binary companion star removes the outer layers.

The latter case does not require a very massive star. Because these two scenarios predict vastly different progenitor stars, direct detection of the progenitor for this type of supernova can provide definitive clues about the preferred evolutionary path.

When young Type Ib supernova iPTF13bvn was discovered in nearby spiral galaxy NGC 5806, astronomers hoped to find its progenitor.

Inspecting the available HST images did indeed reveal an object, providing optimism that the first hydrogen-free supernova progenitor would at last be identified.

Due to the object's blue hue, it was initially suggested that the object was a very hot, very massive, evolved star with a compact structure, called a "Wolf-Rayet" star.

NB: Using models of such stars, a group based in Geneva was able to reproduce the brightness and color of the pre-explosion object with a Wolf-Rayet star that was born with over 30 times the mass of the Sun and died with 11 times the solar mass.

Supernova iPTF13bvn discovered in nearby spiral galaxy NGC 5806. 

Credit: Jean Marie Llapasset

"Based on such suggestions, we decided to check if such a massive star is consistent with the supernova brightness evolution," says Melina Bersten.

However, the results are inconsistent with a Wolf-Rayet star; the exploding star must have been merely four times the mass of the Sun, which is much smaller than a Wolf-Rayet star.

"If the mass was this low and the supernova lacked hydrogen, our immediate conclusion is that the progenitor was part of a binary system," adds Bersten.

More information: The Astronomical Journal, 148:68 (6pp), 2014 October. DOI: 10.1088/0004-6256/148/4/68

CASTRO Simulations reveal an unusual death for ancient stars

This image is a slice through the interior of a supermassive star of 55,500 solar masses along the axis of symmetry. 

It shows the inner helium core in which nuclear burning is converting helium to oxygen, powering various fluid instabilities (swirling lines). 

This "snapshot" from a CASTRO simulation shows one moment a day after the onset of the explosion, when the radius of the outer circle would be slightly larger than that of the orbit of the Earth around the sun. 

Visualizations were done in VisIT. 

Credit: Ken Chen, University of California at Santa Cruz

Certain primordial stars, those 55,000 and 56,000 times the mass of our Sun, or solar masses, may have died unusually.

In death, these objects, among the Universe's first-generation of stars, would have exploded as supernovae and burned completely, leaving no remnant black hole behind.

Astrophysicists at the University of California, Santa Cruz (UCSC) and the University of Minnesota came to this conclusion after running a number of supercomputer simulations at the US Department of Energy's (DOE's) National Energy Research Scientific Computing Center (NERSC) and Minnesota Supercomputing Institute at the University of Minnesota.

They relied extensively on CASTRO, a compressible astrophysics code developed at DOE's Lawrence Berkeley National Laboratory's (Berkeley Lab's) Computational Research Division (CRD).

Their findings were recently published in Astrophysical Journal (ApJ).

First-generation stars are especially interesting because they produced the first heavy elements, or chemical elements other than hydrogen and helium.

In death, they sent their chemical creations into outer space, paving the way for subsequent generations of stars, solar systems and galaxies.

With a greater understanding of how these first stars died, scientists hope to glean some insights about how the Universe, as we know it today, came to be.

"We found that there is a narrow window where supermassive stars could explode completely instead of becoming a supermassive black hole, no one has ever found this mechanism before," says Ke-Jung Chen, a postdoctoral researcher at UCSC and lead author of the ApJ paper.

"Without NERSC resources, it would have taken us a lot longer to reach this result."

"From a user perspective, the facility is run very efficiently and it is an extremely convenient place to do science."

More information: Astrophysical Journal, iopscience.iop.org/0004-637X/790/2/162

NASA X-Calibur: Black hole seeking telescope carried by giant balloon

High pressure helium is used to inflate the balloon that will carry X-Calibur high into the atmosphere. 

This photo of the balloon was taken during a previous mission in Antarctica. 

Credit: NASA

Scientists from NASA's Scientific Balloon Facility and University of Washington in St. Louis will soon launch a telescope with a giant balloon, planning the launch for sometime later this month.

Reaching heights of around 120,000 feet, the balloon will carry a polarimeter telescope meant to search for black holes.

X-Calibur, a polarimeter telescope measures a powerful kind of X-Ray that is emitted by objects being pulled into a black hole.

Black holes don't even let light escape their incredible gravity, and that's why scientists need a certain kind of telescope that can identify the X-Rays on the fringes of the black hole, which will give them an idea of its size and rotation speed.

Part of the goal of the mission is to test Einstein's theory of general relativity, which set certain parameters for how fast he believed a black hole can spin.

Launch Preparation

Scott Barthelmy, a researcher at NASA's Goddard Space Flight Center in Greenbelt, Maryland, described the complicated pre-launch procedure needed to inflate the balloon and prep X-Calibur for flight.

The first step will be to roll out the ultra-thin plastic sheets of the balloon. Hoses will then pump pressurized helium into the balloon, which will expand and cause the balloon to rise in a mushroom-shaped cloud, until the 40-million-cubic foot (1,132,674 cubic meters) interior is full.

The ground weight will then be lifted off the balloon to let it rise. About 900 feet (274 m) of balloon material will be rolled out on the ground, and as the balloon rises it will pick up more and more of this train.

The very end of the balloon will be attached to X-Calibur.

A small crane will cradle X-Calibur about 10 feet (3 m) over the ground.

When the balloon drifts directly over the telescope and begins pulling up, a technician will be standing by to release the telescope from the crane.

If the release comes too early, the telescope could drop to the ground and smash. If it comes too late, the crane release could jam.

NASA's Columbia Scientific Balloon Facility website will host a live broadcast of the launch, which the scientists expect will happen around Sept. 14 or 15, if weather conditions allow. After the balloon launches, anyone can track its progress with a live Google map.

Scientists find Jupiter and Saturn are awash in diamonds

Recent work by planetary scientists has indicated that the deep atmospheres of Jupiter and Saturn may contain chunks of diamond floating in a liquid hydrogen/helium fluid.

Planetary scientists Mona L. Delitsky of California Specialty Engineering in Pasadena, California, and Kevin H. Baines of the University of Wisconsin-Madison have compiled recent data about the phase diagram of carbon and combined them with newly published adiabats (pressure-temperature diagrams) for Jupiter and Saturn to calculate that diamond will be stable in the deep interiors.

Further, at altitudes below the regions where diamond is stable, the pressures and temperatures will be so large as to melt the diamond into liquid, creating diamond rain or liquid diamond.

Recent publications by Nettelmann et al. (2008, 2011) have reported improved adiabats based on new equations of state for the materials inside of Jupiter and Saturn, and new experiments by researchers at Sandia Laboratories and Lawrence Livermore National Laboratory using shockwave techniques (notably those of Knudson et al. 2008 and Eggert et al. 2010) have given clear boundaries for the different phases of carbon.

Delitsky and Baines are reporting that elemental carbon such as soot or graphite generated in Saturn's enormous lightning storms will descend into the planet and will be crushed into diamonds at deep altitudes and then melted into liquid diamond near the cores of the planets.

While it has been known for 30 years that diamond may be stable in the cores of Uranus and Neptune, Jupiter and Saturn were thought to be too hot or to not have conditions suitable for precipitation of solid diamond.

The cores of Uranus and Neptune are too cold to melt diamond. The new data available has confirmed that at depth, diamonds may be floating around inside of Saturn, some growing so large that they could perhaps be called "diamondbergs."

In a recent book, Alien Seas, (Springer 2013), edited by renowned space artist Michael Carroll, a chapter by Baines and Delitsky entitled "The Seas of Saturn" was published. Using this new accurate data, a story about robot mining ships plying the deep interior of Saturn in the far distant future and collecting chunks of diamond was described.

The artwork (see images, below) shows robot hands reaching out to capture diamonds and collect them for transport to Earth.

Because of this new information, theorists Delitsky and Baines report that "diamonds are forever on Uranus and Neptune and not on Jupiter and Saturn."

ESA Herschel: Deep-space Infra-red telescope runs out of Helium Coolant

Europe's deep-space Herschel telescope has given up the ghost -- running out of coolant after a successful mission to observe the birth of stars and galaxies, the European Space Agency said Monday.

"Herschel has made over 35,000 scientific observations, amassing more than 25,000 hours' worth of science data from about 600 observing programmes," it said in a eulogy.

"The archive will become the legacy of the mission. It is expected to provide even more discoveries than have been made during the lifetime of the Herschel mission."

Launched in May 2009, Herschel carried 2,300 litres of liquid helium coolant, which has been slowly evaporating.

Herschel became the largest and most powerful infrared telescope in space. Its expected lifetime was 3.5 years.

The helium was used to cool the satellite's instruments to near absolute zero (minus 273.15 degrees Celsius or minus 459.67 degrees Fahrenheit) to enable it to make its observations.

At 7.5 metres (24.3 feet) high and four metres (13 feet) wide, Herschel had a launch mass of 3.4 tonnes. It cost 1.1 billion euros ($1.4 billion)

It was named after Sir William Herschel, the German-born British astronomer who discovered Uranus in 1781 and infrared radiation in 1800.

It carried three cameras and spectrometers and a primary mirror 3.5 metres (11.37 feet) across -- able to collect almost 20 times more light than any previous infrared space telescope.

Its infrared technology allowed Herschel to see galaxies that were previously hidden from scientists' view by cosmic dust clouds.

In 2011, it was reported that Herschel found the first confirmed evidence of oxygen molecules in space.

"Herschel has offered us a new view of the hitherto hidden Universe, pointing us to a previously unseen process of star birth and galaxy formation, and allowing us to trace water through the Universe from molecular clouds to newborn stars and their planet-forming discs and belts of comets," said Goran Pilbratt, an ESA Herschel Project Scientist.

The telescope will still be able to communicate with its ground stations for some time, placed in a "parking orbit" around the Sun.

Antartica BLAST sub-millimeter Telescope: Balloon-mounted

NASA's balloon-carried BLAST sub-millimeter telescope is hoisted into launch position on Dec. 25, 2012, at McMurdo Station in Antarctica on a mission to peer into the cosmos.

CREDIT: NASA/Wallops Flight Facility

A giant helium balloon is slowly drifting above Antarctica, about 22 miles (36 kilometers) up.

Launched on Tuesday (Dec. 25) from the National Science Foundation's Long Duration Balloon (LDB) facility on Earth's southernmost continent, it carries a sensitive telescope that measures sub-millimeter light waves from stellar nurseries in our Milky Way.

"Christmas launch!" wrote officials with NASA's Wallops Flight Facility, which oversees the agency's balloon research program, in a Twitter post yesterday. "BLAST launched today from McMurdo Station, Antarctica."

This is the fifth and final mission for BLAST, short for the Balloon-borne Large-Aperture Submillimeter Telescope, and mission designers hope it will reveal why so few stars are born in our galaxy.

Lunar Reconnaissance Orbiter spectrometer detects helium in Moon's atmosphere

The Lyman Alpha Mapping Project (LAMP) aboard LRO (shown here in a pre-flight photo) uses a novel method to peer into the perpetual darkness of the moon's so-called permanently shadowed regions.

LAMP "sees" the lunar surface using the ultraviolet light from nearby space and stars, which bathes all bodies in space in a soft glow of ultraviolet light. (Credit: NASA Goddard/Debbie McCallum)

Geophysical Research Letters, Vol. 39, doi:10.1029/2012GL051797 , 2012.

Scientists using the Lyman Alpha Mapping Project (LAMP) aboard NASA's Lunar Reconnaissance Orbiter have made the first spectroscopic observations of the noble gas helium in the tenuous atmosphere surrounding the Moon.

These remote-sensing observations complement in-situ measurements taken in 1972 by the Lunar Atmosphere Composition Experiment (LACE) deployed by Apollo 17.

Although LAMP was designed to map the lunar surface, the team expanded its science investigation to examine the far ultraviolet emissions visible in the tenuous atmosphere above the lunar surface, detecting helium over a campaign spanning more than 50 orbits.

Because helium also resides in the interplanetary background, several techniques were applied to remove signal contributions from the background helium and determine the amount of helium native to the Moon.

Geophysical Research Letters published a paper on this research in 2012. "The question now becomes, does the helium originate from inside the Moon, for example, due to radioactive decay in rocks, or from an exterior source, such as the solar wind?" says Dr. Alan Stern, LAMP principal investigator and associate vice president of the Space Science and Engineering Division at Southwest Research Institute.

With support from LRO's suite of instruments, LAMP has previously determined that hydrogen, mercury and other volatile substances are present in the permanently shaded regions (PSRs) of the moon.

It has also observed PSRs are darker at far-ultraviolet wavelengths and redder than nearby surfaces that receive sunlight.

These darker regions indicate "fluffy" soils, while the reddening is consistent with the presence of water frost.

In a related study led by Dr. Paul Feldman of Johns Hopkins University and published in Icarus, observations showed day-to-day variations in helium abundances, possibly varying with the solar wind, and also significantly decreasing when the Moon passed behind Earth out of sight from the solar wind.

"If we find the solar wind is responsible, that will teach us a lot about how the same process works in other airless bodies," says Stern.

 If spacecraft observations show no such correlation, radioactive decay or other internal lunar processes could be producing helium that diffuses from the interior or that releases during lunar quakes.

NASA Hubble Image: Camelopardalis, A Red Giant Blows a Bubble

Camelopardalis, or U Cam for short, is a star nearing the end of its life. As stars run low on fuel, they become unstable.

Every few thousand years, U Cam coughs out a nearly spherical shell of gas as a layer of helium around its core begins to fuse.

The gas ejected in the star’s latest eruption is clearly visible in this picture as a faint bubble of gas surrounding the star.

U Cam is an example of a carbon star, a rare type of star with an atmosphere that contains more carbon than oxygen.

Due to its low surface gravity, typically as much as half of the total mass of a carbon star may be lost by way of powerful stellar winds.

Located in the constellation of Camelopardalis (The Giraffe), near the North Celestial Pole, U Cam itself is much smaller than it appears in this Hubble image.

In fact, the star would easily fit within a single pixel at the center of the image.

Its brightness, however, is enough to saturate the camera's receptors, making the star look much larger than it is.

The shell of gas, which is both much larger and much fainter than its parent star, is visible in intricate detail in Hubble’s portrait.

This phenomenon is often quite irregular and unstable, but this shell of gas expelled from U Cam is almost perfectly spherical.

Image Credit: ESA/NASA

The Star, which was then called Camelopardus, was introduced by Petrus Plancius in the early 1600's. He was a Dutch astronomer, cartographer and clergyman.

South Pole Station makes the most of liquid helium supply

Image: A 4,000-gallon helium dewar is unloaded from an LC-130 at the South Pole Station. Such shipments may soon cease as experiments move away from using liquid helium to cool telescope sensors. 

Photo Credit: Paul Sullivan

Helium, it's not just good for party balloons.

At one of the coldest places on the planet -- where the temperature bolts down to minus 100 degrees Fahrenheit during the winter months -- liquid helium has been used to super-cool special telescopes designed to peer into the mysteries of the early universe.

However, the use of bulk liquid helium may also become a thing of the past, as the astrophysical experiments at the South Pole Station complete a conversion to a Cryocooler technology that cools telescope sensors to a temperature just above that of outer space by using and recapturing helium gas.

Helium is a limited resource that promises to become even scarcer and more expensive in the future. A bipartisan bill being considered in the U.S.

Senate this year would help conserve the nation's helium reserves -- locked up underground in a natural geological formation near Amarillo, Texas -- and give priority to federally funded researchers in times of shortage.

The South Pole Station has done its part over the last decade or so to stretch out the nation's helium supply, which is used in everything from the manufacture of fiber optics and microchips to cooling the superconducting magnets used in MRI machines.

The zero boil-off system now at the South Pole ensures that almost no helium is lost to the atmosphere.

Water, of course, has a boiling point of 100 degrees Celsius, transitioning from a liquid to a gas. Helium also has a boiling point, but a wee bit lower -- minus 269C.

On the Kelvin scale, that's about 4.2 degrees above absolute zero, the temperature at which all molecular motion stops. The temperature of outer space is about 3 Kelvin.

The telescopes at the South Pole do not operate in the visible light spectrum, but instead measure microwave radiation.

The telescope sensors use superconductive materials that must be cooled down to 250 milliKelvin, just a quarter of a degree above absolute zero, to study the cosmic microwave background, often described as an afterglow of the Big Bang when the universe burst into existence.

Liquid helium has been an integral part of cryogenic techniques since astrophysical experiments began at the South Pole in the 1980s, according to Paul Sullivan, South Pole Station manager of science support.

Read the full article: Full of cold air

Hubble Archive Image: Old star reveals Arsenic and Selenium

An ultraviolet spectrum taken from the Hubble Space Telescope public archives revealed arsenic and selenium in a 12 billion year-old halo star dubbed HD 160617.

"Arsenic and selenium elements were forged in an even older star, which has long since disappeared, and then-like genes passed on from parent to infant-they were born into the star we see today, HD 160617." reported Ian Roederer, along with co-author James Lawler.

The Big Bang produced lots of hydrogen and helium and a smidgen of lithium.

All heavier elements found on the periodic table have been produced by stars over the last 13.7 billion years. Astronomers analyze starlight to determine the chemical makeup of stars, the origin of the elements, the ages of stars, and the evolution of galaxies and the universe.

Now for the first time, astronomers have detected the presence of arsenic and selenium, neighbouring elements near the middle of the periodic table, in an ancient star in the faint stellar halo that surrounds the Milky Way.

Arsenic and selenium are elements at the transition from light to heavy element production, and have not been found in old stars until now.

Lead author of the Astrophysical Journal paper, Fellow Ian Roederer of the Carnegie Observatories explained: "Stars like our Sun can make elements up to oxygen on the periodic table. Other more massive stars can synthesize heavier elements, those with more protons in their nuclei, up to iron by nuclear fusion-the process in which atomic nuclei fuse and release lots of energy. Most of the elements heavier than iron are made by a process called neutron-capture nucleosynthesis."

"Although neutrons have no charge, they can decay into protons after they're in the nucleus, producing elements with larger atomic numbers. One of the ways that this method can work is by exposure to a burst of neutrons during the violent supernova death of a star."

"We call this process the rapid process (r-process). It can produce elements at the middle and bottom of the periodic table-from zinc to uranium-in the blink of an eye."

Roederer, with co-author James Lawler, looked at an ultraviolet spectrum from the Hubble Space Telescope public archives to find arsenic and selenium in a 12 billion year-old halo star dubbed HD 160617.

"These elements were forged in an even older star, which has long since disappeared, and then-like genes passed on from parent to infant-they were born into the star we see today, HD 160617."

The team also examined data for this star from the public archives of several ground-based telescopes and were able to detect 45 elements. In addition to arsenic and selenium, they found rarely seen cadmium, tellurium, and platinum, all of which were produced by the r-process.

This is the first time these elements have been detected together outside the Solar System. Astronomers cannot replicate the r-process in any laboratory since the conditions are so extreme. The key to modeling the r-process relies on astronomical observations.

"What I find exciting is that arsenic and selenium can be found in other stars, even ones like HD 160617 that we've been studying for decades," remarked Roederer.

"Now that we know where to look, we can go back and study these elements in other stars. Understanding the r-process helps us know why we find certain elements like barium on Earth, or understand why uranium is so rare."

ESA ESO VLT: Newborn Massive Stars Dwarf Full-Grown Stellar Giants

Artist’s impression illustrating the formation process of massive stars. 

At the end of the formation process, the surrounding accretion disk disappears, revealing the surface of the young star. 

At this phase the young massive star is much larger than when it has reached a stable equilibrium.

CREDIT: Lucas Ellerbroek/Lex Kaper University of Amsterdam

Massive stars generally start out life much bigger than they will be in maturity, a new study seems to confirm.

Astronomers from the University of Amsterdam got a rare look at a massive star in the process of forming and found that the star will contract until it has reached a stable equilibrium.

The researchers studied the young star B275, which lies in the Omega Nebula, also called the Swan Nebula or Messier 17. This hotbed of gas, dust and young stars lies approximately 5,500 light-years from Earth, in the direction of the Sagittarius constellation.

Astronomers typically struggle to obtain clear observations of a massive star as it is forming, since newborn stars are deeply embedded and obscured in their parent clouds of gas and dust.

Peering through the haze
To lift the veil on the process of star formation, the researchers sifted through ultraviolet and infrared data collected from a powerful spectrograph instrument, called the X-shooter, on the European Space Agency's Very Large Telescope at the Paranal Observatory in Chile.

"The large-wavelength coverage of X-shooter provides the opportunity to determine many stellar properties at once, like the surface temperature, size, and the presence of a disk," study lead author Bram Ochsendorf said in a statement.

Ochsendorf analyzed the data as part of his master's research project at the University of Amsterdam.

The results indicate that B275 is about three times larger than stars that are about seven times more massive than our sun and have reached the so-called main sequence phase of their lives.

The main sequence phase represents a specific stage of stellar evolution in which a star burns hydrogen into helium. (Our own sun is currently in its main sequence.)

The team's findings appear to confirm a theory of star formation predicting that a newly formed massive star will contract until it reaches a more stable state.

A Freaky Fluid inside Jupiter

"Liquid metallic hydrogen has low viscosity, like water, and it's a good electrical and thermal conductor," says Caltech's David Stevenson, an expert in planet formation, evolution, and structure.

Last Friday, August 5th, NASA's Juno spacecraft blasted off on a 5-year voyage to a freakish world: planet Jupiter.

Jupiter has a long list of oddities. For one thing, it's enormous, containing 70% of our solar system's planetary material, yet it is not like the rocky world beneath our feet. Jupiter is so gassy, it seems more like a star.

Jupiter's atmosphere brews hurricanes twice as wide as Earth itself, monsters that generate 400 mph winds and lightning 100 times brighter than terrestrial bolts. The giant planet also emits a brand of radiation lethal to unprotected humans.

Jupiter's strangest feature, however, may be a 25,000 mile deep soup of exotic fluid sloshing around its interior. It's called liquid metallic hydrogen.

"Here on Earth, hydrogen is a colorless, transparent gas," says Juno principal investigator Scott Bolton. "But in the core of Jupiter, hydrogen transforms into something bizarre."

Jupiter is 90% hydrogen1, with 10% helium and a sprinkle of all the other elements. In the gas giant's outer layers, hydrogen is a gas just like on Earth.

As you go deeper, intense atmospheric pressure gradually turns the gas into a dense fluid.2 Eventually the pressure becomes so great that it squeezes the electrons out of the hydrogen atoms and the fluid starts to conduct like a metal.

What's this fluid like?

"Liquid metallic hydrogen has low viscosity, like water, and it's a good electrical and thermal conductor," says Caltech's David Stevenson, an expert in planet formation, evolution, and structure.

"Like a mirror, it reflects light, so if you were immersed in it [here's hoping you never are], you wouldn't be able to see anything."

Here on Earth, liquid metallic hydrogen has been made in shock wave experiments, but since it doesn't stay in that form it has only been made in tiny quantities for very short periods of time. If researchers are right, Jupiter's core may be filled with oceans of the stuff.

There's so much LMH inside Jupiter that it transforms the planet into an enormous generator. "A deep layer of liquid metallic hydrogen and Jupiter's rapid rotation (about 10 hours) create a magnetic field 450 million miles long - the biggest entity in the solar system," says Bolton.

Jupiter's magnetosphere can produce up to 10 million amps of electric current, with auroras that light up Jupiter's poles more brightly than any other planet.

Although scientists are fairly sure that liquid metallic hydrogen exists inside Jupiter, they don't know exactly how the big planet's interior is structured. For instance, where does the hydrogen turn into a conductor? Does Jupiter have a core of heavy elements inside?

Juno's mission is to answer those key questions.

Hubble Uncovers An Overheated Early Universe

This is the conclusion of a team of astronomers who used the new capabilities of NASA's Hubble Space Telescope to probe the invisible, remote universe.

Using the newly installed Cosmic Origins Spectrograph (COS) they have identified an era, from 11.7 to 11.3 billion years ago, when the universe stripped electrons off from primeval helium atoms - a process called ionization.

This process heated intergalactic gas and inhibited it from gravitationally collapsing to form new generations of stars in some small galaxies. The lowest-mass galaxies were not even able to hold onto their gas, and it escaped back into intergalactic space.

Michael Shull of the University of Colorado and his team were able to find the telltale helium spectral absorption lines in the ultraviolet light from a quasar - the brilliant core of an active galaxy.

The quasar beacon shines light through intervening clouds of otherwise invisible gas, like a headlight shining through a fog. The beam allows for a core-sample probe of the clouds of gas interspersed between galaxies in the early universe.

The universe went through an initial heat wave over 13 billion years ago when energy from early massive stars ionized cold interstellar hydrogen from the big bang. This epoch is actually called reionization because the hydrogen nuclei were originally in an ionized state shortly after the big bang.

But Hubble found that it would take another 2 billion years before the universe produced sources of ultraviolet radiation with enough energy to do the heavy lifting and reionize the primordial helium that was also cooked up in the big bang.

This radiation didn't come from stars, but rather from quasars. In fact the epoch when the helium was being reionized corresponds to a transitory time in the universe's history when quasars were most abundant.

The universe was a rambunctious place back then. Galaxies frequently collided, and this engorged supermassive black holes in the cores of galaxies with infalling gas. The black holes furiously converted some of the gravitational energy of this mass to powerful far-ultraviolet radiation that would blaze out of galaxies.

This heated the intergalactic helium from 18,000 degrees Fahrenheit to nearly 40,000 degrees. After the helium was reionized in the universe, intergalactic gas again cooled down and dwarf galaxies could resume normal assembly. "I imagine quite a few more dwarf galaxies may have formed if helium reionization had not taken place," said Shull.

So far Shull and his team only have one sightline to measure the helium transition, but the COS science team plans to use Hubble to look in other directions to see if the helium reionization uniformly took place across the universe.

Helium clue found in echo of the big bang - space

Helium clue found in echo of the big bang - - New Scientist

THE subtle signal of ancient helium has shown up for the first time in light left over from the big bang. The discovery will help astronomers work out how much of the stuff was made during the big bang and how much was made later by stars.

Helium is the second-most abundant element in the universe after hydrogen. The light emitted by old stars and clumps of hot pristine gas from the early universe suggest helium made up some 25 per cent of the ordinary matter created during the big bang.

The new data provides another measure. A trio of telescopes has found helium's signature in the cosmic microwave background (CMB, pictured), radiation emitted some 380,000 years after the big bang. The patterns in this radiation are an important indicator of the processes at work at that time. Helium affects the pattern because it is heavier than hydrogen and so alters the way pressure waves must have travelled through the young cosmos. But helium's effect on the CMB was on a scale too small to resolve until now.

Cosmic Treasure Trove of Heavy Metals Found

Cosmic Treasure Trove of Heavy Metals Found

An orbiting X-ray observatory has found the largest known reservoir of rare heavy metals in the universe.

The lightweights of the periodic table, hydrogen and helium, are the most abundant elements in the cosmos — they're the key fuels of stellar engines.

But more familiar to us Earthlings are the heavier elements that make up the rest of the table, though these heftier elements are rare in the universe at large.

Recently, astronomers used the Suzaku orbiting X-ray observatory, operated jointly by NASA and the Japanese space agency, to discover the largest known cache of rare metals in the universe to date.

Suzaku detected the elements chromium and manganese while observing the central region of the Perseus galaxy cluster, which lies 225 million light-years from Earth. The metallic atoms are part of the hot gas, or intergalactic medium, that lies between 190 galaxies within the cluster.

"This is the first detection of chromium and manganese from a cluster," says Takayuki Tamura, an astrophysicist at the Japan Aerospace Exploration Agency who led the Perseus study. "Previously, these metals were detected only from stars in the Milky Way or from other galaxies. This is the first detection in intergalactic space."