We’re all watching what’s happening with Comet ISON, and today, November 21, 2013 Astronomy Magazine and Discover Magazine are hosting a “Countdown to Comet ISON” Google Hangout event, where the magazines’ expert editors will have all your comet questions answered. all the action starts at 20:00 UTC (3 pm EST). With ISON reaching its brightest this month, Astronomy Editor-in-Chief Dave Eicher, Discover Editor-at-Large Corey Powell and several others will discuss things like:
· When and where can you spot Comet ISON?
· How best to photograph the comet
· What scientists hope to learn from ISON
· Other amazing facts about comets across the ages
We’ll post the video feed here when it goes live, but can also watch (and RSVP) at the G+ event page.
If you miss it live, you can watch the replay above.
The International Space Station in March 2009 as seen from the departing STS-119 space shuttle Discovery crew. Credit: NASA/ESA
Time to pull out your 3-D glasses (the red-blue kind works the best) and take a virtual spacewalk with this new video from ESA. It gives you that “Gravity”-type experience — without the spinning. But as you travel around on your jetpack, this VR video gives you a good appreciation for the size of the ISS. You also get to watch a Soyuz spacecraft undock and the docking of an Automated Transfer Vehicle.
The lunar dust detector (visible on the far left of this Apollo 12 experiment package in 1969) measured dust build-up on the moon. Credit: NASA
Dust on the moon accumulates at a rate 10 times faster than previously believed, which could make it difficult for future human explorers to use solar power cells on the lunar surface, a new study says.
“You wouldn’t see it; it’s very thin indeed,” stated Brian O’Brien, a University of Western Australia professor who co-authored the research. “But, as the Apollo astronauts learned, you can have a devil of a time overcoming even a small amount of dust.”
O’Brien also developed the Lunar Dust Detector, an experiment that flew aboard three Apollo moon missions in the 1960s and 1970s. The experiment, which was about the size of a matchbox, had three tiny solar cells on board. Voltage from the experiment fell as dust accumulated.
His experiment was deployed on Apollo 12 (in 1969) and Apollos 14 and 15 (in 1971), then shut off in 1977 due to budget cutbacks.
In these years of data, electrical measurements showed that 100 microgams of lunar dust fell per year per square centimeter. “At that rate, a basketball court on the Moon would collect roughly 450 grams (1 pound) of lunar dust annually,” stated a press release from the American Geophysical Union.
Past models assumed that the dust built up because of meteor impacts and cosmic dust, but O’Brien’s data was far in excess of that. He suggested it could be because the moon has a “dust atmosphere” built up as individual particles jump between different locations.
“During each lunar day, solar radiation is strong enough to knock a few electrons out of atoms in dust particles, building up a slight positive charge,” the AGU stated.
“On the nighttime side of the Moon, electrons from the flow of energetic particles, called the solar wind, which comes off the sun strike dust particles and give them a small negative charge. Where the illuminated and dark regions of the moon meet, electric forces could levitate this charged dust, potentially lofting grains high into the lunar sky.”
Artist’s conception of NASA’s Lunar Atmosphere and Dust Environment Explorer (LADEE) orbiting above the moon. Credit: NASA Ames/Dana Berry
This data especially has resonance for NASA now that its Lunar Atmosphere and Dust Environment Explorer (LADEE) spacecraft is orbiting about 155 miles (250 kilometers) above the moon. The agency is trying to learn more about how the dust environment on the moon works, particularly at the “terminator” — the point between light and darkness — where dust may levitate due to electrostatic charging.
“Something similar was reported by Apollo astronauts orbiting the Moon who looked out and saw dust glowing on the horizon,” stated Monique Hollick, who led the work and is also a researcher at the University of Western Australia.
The Surface Electrical Properties experiment deployed on the Apollo 17 mission. Scientists are concerned that solar panels, such as the one visible on this experiment, could quickly become unusable due to the buildup of lunar dust. Credit: NASA
NASA believed O’Brien’s data was lost for decades as the agency did not preserve the archival tapes, but in 2006 O’Brien — when he heard of NASA’s issue — informed them he still had the data.
“It’s been a long haul,” stated O’Brien. “I invented [the detector] in 1966, long before Monique was even born. At the age of 79, I’m working with a 23-year old working on 46-year-old data and we discovered something exciting—it’s delightful.”
The work was published this week in Space Weather and is available here.
Artist concept of a solar sail demonstration mission that will use lasers for navigation. Credit: NASA.
Since the beginning of the space age, radio waves have been used for communication with spacecraft. But last month, NASA’s Lunar Laser Communication Demonstration (LLCD) made history by using a pulsed laser beam to transmit data over the 385,000 km (239,000 miles) between the Moon and Earth at a record-breaking download rate of 622 megabits per second (Mbps). This was NASA’s first system for two-way communication using a laser instead of radio waves. In our previous article today, we described how NASA will test out the Optical PAyload for Lasercomm Science (OPALS) on the International Space Station to demonstrate how videos can be beamed to Earth via laser beam.
What are the challenges in testing out an entirely new way of doing communications and other systems like navigation using lasers in space?
Don Cornwell, LLCD manager, discusses the challenges and successes they’ve had so far in this new video:
“The big change is the ability to do it by light, because the data rates that we’ve now done are just the opening shot, so to speak,” Cornwell said. “Radio communications systems have served us very well for the past 50 years but they are starting to run out of bandwidth, so in other words because of the frequency they use you can only modulate a certain portion of that frequencies and unless you move to higher frequencies – and light is a higher frequency than radio waves– you can’t squeeze a lot more bandwidth out, but the light systems in space, … we’ve now opened up a whole new field where we’re getting started , but the sky’s the limit regarding how much we can do there.”
Using lasers will allow for increased bandwidth for image resolution and 3-D video transmission from deep space, as well as allowing for tele-operation for long distances, such as from the Earth to the Moon.
LLCD is a short-duration experiment and the precursor to NASA’s long-duration demonstration, the Laser Communications Relay Demonstration (LCRD). LCRD is a part of the agency’s Technology Demonstration Missions Program, which is working to develop crosscutting technology capable of operating in the rigors of space. It is scheduled to launch in 2017.
Meanwhile, NASA has three other laser technology demonstration missions in the offing, likely launching in 2015 and 2016. One is a solar sail demonstration will enable propellantless laser in-space navigation for missions such as advanced geostorm warning, economic orbital debris removal, and deep space exploration.
They are what is known as the “lighthouses” of the universe – rotating neutron stars that emit a focused beam of electromagnetic radiation that is only visible if you’re standing in it’s path. Known as pulsars, these stellar relics get their name because of the way their emissions appear to be “pulsating” out into space.
Not only are these ancient stellar objects very fascinating and awesome to behold, they are very useful to astronomers as well. This is due to the fact that they have regular rotational periods, which produces a very precise internal in its pulses – ranging from milliseconds to seconds.
Description:
Pulsars are types of neutron stars; the dead relics of massive stars. What sets pulsars apart from regular neutron stars is that they’re highly magnetized, and rotating at enormous speeds. Astronomers detect them by the radio pulses they emit at regular intervals.
An artist’s impression of an accreting X-ray millisecond pulsar. The flowing material from the companion star forms a disk around the neutron star which is truncated at the edge of the pulsar magnetosphere. Credit: NASA / Goddard Space Flight Center / Dana Berry
Formation:
The formation of a pulsar is very similar to the creation of a neutron star. When a massive star with 4 to 8 times the mass of our Sun dies, it detonates as a supernova. The outer layers are blasted off into space, and the inner core contracts down with its gravity. The gravitational pressure is so strong that it overcomes the bonds that keep atoms apart.
Electrons and protons are crushed together by gravity to form neutrons. The gravity on the surface of a neutron star is about 2 x 1011 the force of gravity on Earth. So, the most massive stars detonate as supernovae, and can explode or collapse into black holes. If they’re less massive, like our Sun, they blast away their outer layers and then slowly cool down as white dwarfs.
But for stars between 1.4 and 3.2 times the mass of the Sun, they may still become supernovae, but they just don’t have enough mass to make a black hole. These medium mass objects end their lives as neutron stars, and some of these can become pulsars or magnetars. When these stars collapse, they maintain their angular momentum.
But with a much smaller size, their rotational speed increases dramatically, spinning many times a second. This relatively tiny, super dense object, emits a powerful blast of radiation along its magnetic field lines, although this beam of radiation doesn’t necessarily line up with it’s axis of rotation. So, pulsars are simply rotating neutron stars.
And so, from here on Earth, when astronomers detect an intense beam of radio emissions several times a second, as it rotates around like a lighthouse beam – this is a pulsar.
History:
The first pulsar was discovered in 1967 by Jocelyn Bell Burnell and Antony Hewis, and it surprised the scientific community by the regular radio emissions it transmitted. They detected a mysterious radio emission coming from a fixed point in the sky that peaked every 1.33 seconds. These emissions were so regular that some astronomers thought it might be evidence of communications from an intelligent civilization.
Although Burnell and Hewis were certain it had a natural origin, they named it LGM-1, which stands for “little green men”, and subsequent discoveries have helped astronomers discover the true nature of these strange objects.
Astronomers theorized that they were rapidly rotating neutron stars, and this was further supported by the discovery of a pulsar with a very short period (33-millisecond) in the Crab nebula. There have been a total of 1600 found so far, and the fastest discovered emits 716 pulses a second.
Later on, pulsars were found in binary systems, which helped to confirm Einstein’s theory of general relativity. And in 1982, a pulsar was found with a rotation period of just 1.6 microseconds. In fact, the first extrasolar planets ever discovered were found orbiting a pulsar – of course, it wouldn’t be a very habitable place.
Interesting Facts:
When a pulsar first forms, it has the most energy and fastest rotational speed. As it releases electromagnetic power through its beams, it gradually slows down. Within 10 to 100 million years, it slows to the point that its beams shut off and the pulsar becomes quiet.
When they are active, they spin with such uncanny regularity that they’re used as timers by astronomers. In fact, it is said that certain types of pulsars rival atomic clocks in their accuracy in keeping time.
Pulsars also help us search for gravitational waves, probe the interstellar medium, and even find extrasolar planets in orbit. In fact, the first extrasolar planets were discovered around a pulsar in 1992, when astronomers Aleksander Wolszczan and Dale Frail announced the discovery of a multi-planet planetary system around PSR B1257+12 – a millisecond pulsar now known to have two extrasolar planets.
Artist’s impression of the planets orbiting PSR B1257+12. Credit: NASA/JPL-Caltech/R. Hurt (SSC)
It has even been proposed that spacecraft could use them as beacons to help navigate around the Solar System. On NASA’s Voyager spacecraft, there are maps that show the direction of the Sun to 14 pulsars in our region. If aliens wanted to find our home planet, they couldn’t ask for a more accurate map.
Artist's conception of an astronaut installing the Optical PAyload for Lasercomm Science (OPALS) experiment, which will be installed on the Earth-facing side of the International Space Station. Credit: NASA
Videos will beam to Earth on a laser beam in a technology demonstration coming to the International Space Station soon, says NASA’s Jet Propulsion Laboratory.
The Optical PAyload for Lasercomm Science (OPALS) plans to move videos from space to an Optical Communications Telescope Laboratory in Wrightwood, Calif. Each demonstration test will last about 100 seconds, while the station and the ground receiver can “see” each other.
While the experiment sounds awesome for sending back “home videos” from space, NASA is more touting it as a boon for transferring loads of scientific data back to Earth.
“The scientific instruments in near-Earth and deep-space missions increasingly require higher communication rates to transmit their gathered data back to Earth or to support high-data-rate applications (e.g., high-definition video streams),” stated the OPALS webpage at NASA’s Jet Propulsion Laboratory.
“Optical communications (also referred to as ‘lasercomm’) is an emerging technology wherein data is modulated onto laser beams, which offers the promise of much higher data rates than what is achievable with radio-frequency (RF) transmissions.”
How the Optical PAyload for Lasercomm Science (OPALS) experiment will work on the International Space Station. Credit: NASA
The experiment page (last updated in May) says it is intended to work for about a year, with the current Expedition 37/38 and forthcoming 39/40 crews. That said, it appears the payload is not aboard station yet.
A July update from NASA said the SpaceX Dragon spacecraft is supposed to ferry OPALS to space. There hasn’t been a Dragon flight since that time, but SpaceX is listing one more for 2013 on its launch manifest.
Diagram of the Optical PAyload for Lasercomm Science (OPALS) experiment. It includes three elements: (1) a sealed container that includes the laser, a power board and avionics (2) an optical gimbal transceiver that has an uplink camera, and laser collimater for downlink (3) a Flight Releasable Attachment Mechanism (FRAM), a mechanical and electrical link to the International Space Station and launch vehicle. Credit: NASA
Laser communication hit headlines earlier this fall when the NASA Lunar Atmosphere and Dust Environment Explorer (LADEE) sent a packet of information by laser from the moon, breaking records in terms of download rate (622 megabits per second).
An artist’s concept of how the spacecraft for the Inspiration Mars Foundation’s “Mission for America” might be configured. Credit: Inspiration Mars.
CORRECTION: This article has been updated after more information was received from Inspiration Mars. Tito was highlighting other countries’ interest in the Red Planet in his testimony and has no plans at this time to work with anyone but NASA.
Remember that proposal to send a couple in the direction of the Red Planet, loop around it and then come back to Earth? The founder of the Inspiration Mars project, Dennis Tito, outlined more details of his proposal before the House Science Subcommittee on Space yesterday (Nov. 20).
Inspiration Mars has released an Architecture Study Report that is the fruits of a 90-day study done not only by the foundation itself, but also working with “NASA centers and industry partners” to figure out the best way to launch humans there in late 2017 or 2018. But if it’s delayed, Tito is prepared to go to Russia or China instead, he warns.
Here’s the high-level summary:
Two launches using NASA’s forthcoming Space Launch System, one for cargo and one for crew;
The crew module would be from the crew transportation vehicle that NASA selected under its commercial crew program (see this Universe Today story yesterday for an update on funding concerns on that program);
The cargo and crew vehicles would dock in space and then head out to Mars.
Crew of Soyuz TM-32, which flew to the International Space Station in 2001. From left, space tourist Dennis Tito, Russian cosmonaut Talgat Musabayev, and Russian cosmonaut Yuri Baturin. Credit: Wikipedia/NASA
“Given Russia’s clear recognition of the value and prestige of accomplishments in human space exploration, and their long-time interest in exploring Mars, my personal belief is that in all likelihood the Energia super-heavy rocket revival announcement signals Russian intent to fly this mission in 2021,” Tito stated.
“Their heavy lift rocket, along with their other designs for modules and the Soyuz, can fly this mission with modest upgrades to their systems.”
A third option would be using Chinese capabilities, he added, The Chinese may also be interested, he said, because the country — reportedly developing a large space station of its own — is likely “contemplating this opportunity to be the first on Mars.” Tito said he is informing Congress of his plans to go elsewhere as a “civic duty”, and that he wants to give NASA the first shot.
More food for thought as Congress mulls how much money to allocate to NASA in fiscal 2014. And Tito had strong words about his feelings on the funding: “If I may offer a frank word of caution to this subcommittee: The United States will carry out a Mars flyby mission, or we will watch as others do it – leaving us to applaud their skill and their daring.”
A composite image in X-ray and radio showing a likely candidate for a jet emanating from the supermassive black hole at the center of the Milky Way. X-ray: NASA/CXC/UCLA/Z.Li et al; Radio: NRAO/VLA
Jets of high energy particles emanating from a black hole have been detected plenty of times before, but in other galaxies, that is — not from the supermassive black hole at the center of the Milky Way, known as Sagittarius A* (Sgr A*). Previous studies and other evidence suggested that perhaps there were jets – or ghosts of past jets – but many findings and studies often contradicted each other, and none were considered definitive.
Now, astronomers using Chandra X-ray Observatory and the Very Large Array (VLA) radio telescope have found strong evidence Sgr A* is producing a jet of high-energy particles.
“For decades astronomers have looked for a jet associated with the Milky Way’s black hole. Our new observations make the strongest case yet for such a jet,” said Zhiyuan Li of Nanjing University in China, lead author of a study in The Astrophysical Journal.
The supermassive black hole at the center of the Milky Way is about four million times more massive than our Sun and lies about 26,000 light-years from Earth.
While the common notion is that black holes inhale and ingest everything that comes their way, that’s not always true. Sometimes they reject small portions of incoming mass, pushing it away in the form of a powerful jet, and many times a pair of jets. These jets also feed the surroundings, releasing both mass and energy and likely play important roles in regulating the rate of formation of new stars.
Sgr A* is presently known to be consuming very little material, and so the jet is weak, making it difficult to detect. Astronomers don’t see another jet “shooting” in the opposite direction but that may be because of gas or dust blocking the line of sight from Earth or a lack of material to fuel the jet. Or there may be just a single jet.
“We were very eager to find a jet from Sgr A* because it tells us the direction of the black hole’s spin axis. This gives us important clues about the growth history of the black hole,” said Mark Morris of the University of California at Los Angeles, a co-author of the study.
The study shows the spin axis of Sgr A* is pointing in one direction, parallel to the rotation axis of the Milky Way, which indicates to astronomers that gas and dust have migrated steadily into Sgr A* over the past 10 billion years. If the Milky Way had collided with large galaxies in the recent past and their central black holes had merged with Sgr A*, the jet could point in any direction.
The jet appears to be running into gas near Sgr A*, producing X-rays detected by Chandra and radio emission observed by the VLA. The two key pieces of evidence for the jet are a straight line of X-ray emitting gas that points toward Sgr A* and a shock front — similar to a sonic boom — seen in radio data, where the jet appears to be striking the gas. Additionally, the energy signature, or spectrum, in X-rays of Sgr A* resembles that of jets coming from supermassive black holes in other galaxies.
The Chandra observations in this study were taken between September 1999 and March 2011, with a total exposure of about 17 days.
The ORS-3 mission launch as it passed over Beavertail Lighthouse in Jamestown, Rhode Island, USA. Credit and copyright: Scott MacNeil.
Last night’s launch of a Minotaur I rocket from the Mid-Atlantic Regional Spaceport at NASA’s Wallops Flight Facility in eastern Virginia was visible to millions along the east coast of the US and southern Canada, and many were out with their cameras to watch the sight.
The launch sent a record payload of 29 satellites to low Earth orbit, including the first cubesat built by high school students.
Launch occurred at about 8:15 p.m. EST on November 19 (01:15 UTC, Nov. 20).
Minotaur 1 rocket from NASA’s Wallops Flight Facility in Virginia on Nov. 19, 2013. Credit: NASA/Jeremy Eggers.
Approximately 12 minutes after lift-off, the Air Force’s Space Test Program Satellite-3 spacecraft was deployed into its intended orbit at an altitude of approximately 500 km (310 miles). The Minotaur’s upper stage then executed a pre-planned collision avoidance maneuver before starting deployment of 28 CubeSats sponsored by the Department of Defense’s Operationally Responsive Space (ORS) office, the U.S. Air Force Space and Missile Systems Center’s Space Test Program, and NASA’s Educational Launch of Nanosatellites (ELaNa) program.
This was the 25th launch for Orbital Science’s Minotaur rocket, all of which have been successful, and the sixth Minotaur vehicle to be launched from the Wallops facility.
The launch of the Minotaur 1 from NASA’s Wallops Flight Facility was photographed from Lancaster, PA on November 19, 2013. Credit and copyright: Marion Haligowski.
Marion Haligowski took the image above, saying “I should have used a wider lens; I didn’t realize the launch would take up 1/4 of the sky from 154 miles away!” and of her image below she added, “I was surprised how high the separation was from 154 miles away from the Wallops Island launch site.”
Final separation of the Minotaur 1 is seen high in the sky of Lancaster, PA on the evening of November 19, 2013. Two exposures were stacked in StarStaX using a Canon T2i (ISO 400 / 25 seconds) and a 50 mm f/1.4 lens at f/5.6. Credit and copyright: Marion Haligowski.
Our own Jason Major saw the launch from near his home in Rhode Island. “I withstood the cold (and launch delay) to capture this photo of a rising Minotaur I rocket, launched 400 miles south,” Jason said. This is a 15-second exposure.
This was a portion of the second stage flight of a Minotaur I rocket launched from Wallops Island, Virginia, seen from Conimicut Point in Warwick at around 8:17 p.m. EST on Nov. 19, 2013. Credit and copyright: Jason Major.ORS-3 Minotaur Launch Seen from about 150 miles away in western Louisa, VA. The diffuse moonlight nearly washed out the rocket’s “trail” altogether, but fortunately it was still visible. Credit and copyright: David Murr.
Orbital Sciences Corporation’s Twitter feed had a running commentary of the launch activities and posted this image shortly after launch:
Orbital Science Corporation posted this image on their Twitter feed of the launch as seen from the public viewing are at Wallops Flight Facility. Via Orbital.
And the launch was a topic of discussion on Twitter, too:
Just watched @nasa launch a rocket from earth on my phone while waiting for the metro, in case you didn't think the future's great.
Here’s a short timelapse of the launch, viewed from the beach in Cape May, New Jersey. Photographer Frank Miller said that 20 minutes before the 8:15 PM launch, he photographed a meteor streaking south, which is the first “streak” you see in the video:
The next Wallops launch is an Antares rocket with a Cygnus cargo spacecraft targeted for Dec. 15-21, 2013, and as it looks now, it will again be an evening launch, so make your preparations to see it, and we’ll keep you posted on launch dates.
A brown dwarf from the thick-disk or halo is shown. Although astronomers observe these objects as they pass near to the solar system, they spend much of their time away from the busiest part of the Galaxy, and the Milky Way's disk can be seen in the background. Credit: John Pinfield
As the name implies, a brown dwarf is small… only about 7% the size of the Sun. As far as stellar senior citizens go, they’re cool. Zipping along through space at speeds of 100 to 200 kilometers per second, they may have formed back when our galaxy was young – perhaps 10 billion years ago. Now a team of astronomers headed by Dr. David Pinfield at the University of Hertfordshire has identified a pair of the oldest brown dwarfs known… a set of orbs which could be the harbinger of a huge amount of new, unseen objects.
Although we sometimes refer to them as stars, brown dwarfs are in a class of their own. Because they didn’t ignite in nuclear fusion, they don’t generate internal heat like an ordinary star. After they are formed, they continue to cool and fade as time passes. This process makes them very difficult to observe and the discovery of two very old brown dwarfs, with temperatures of 250-600 C is cause for astronomical excitement.
Just how did Pinfield’s team pick such tiny objects out of the vastness of space? The discovery was facilitated thanks to a survey made by the Wide-field Infrared Survey Explorer (WISE), a NASA observatory that scanned the mid-infrared sky from orbit in 2010 and 2011. The ancient objects are cataloged as WISE 0013+0634 and WISE 0833+0052, and they are located in the constellations of Pisces and Hydra. Because they are so elusive, they were also confirmed by large ground-based telescopes (Magellan, Gemini, VISTA and UKIRT).
However, identifying the pair wasn’t easy. Seeing through the eyes of infrared reveals a crowded space – one populated with reddened stars, distant background galaxies and pockets of nebulous gas and dust. Picking out such a small character from a stellar cast would be like finding one tiny pearl in the vastness of an ocean. But Pinfield’s researchers employed a new method which utilizes WISE’s capabilities. As it scanned the sky over and over again, it revealed the cool, brown dwarfs – picking up the faint signature that other searches had missed.
These two particular brown dwarfs are different from the other slow movers of their type. By studying their spectra, the astronomers have identified atmospheres almost entirely comprised of hydrogen. This sets them apart from younger stars which have an abundance of heavier elements. Does being lighter make them speedier? According to Pinfield, “Unlike in other walks of life, the galaxy’s oldest members move much faster than its younger population.”
Stars near to Sun are considered the “local volume” and are created with three overlapping populations – the thin disk, the thick disk and the halo. Each of these layers has a certain amount of age associated with it: the oldest being the thickest and its member stars move up and down at a higher rate of speed. The halo contains both disks, along with the initial materials which formed the very first stars. Thin disk objects abound in the local volume and account for about 97% of the local stars, while thick disk and halo objects are a meager 3%. Chances are, brown dwarfs belong to that smaller percentage which explains why these fast-moving thick-disk/halo objects are only now being revealed.
Just how many may await discovery? Scientists surmise there may be as many as 70 billion brown dwarfs in the galaxy’s thin disk, and the thick disk and halo take up significantly larger galactic volumes. Even at a tiny 3%, this means there could be an army of ancient brown dwarfs in the galaxy. “These two brown dwarfs may be the tip of an iceberg and are an intriguing piece of astronomical archaeology,” said Pinfield. “We have only been able to find these objects by searching for the faintest and coolest things possible with WISE. And by finding more of them we will gain insight into the earliest epoch of the history of the galaxy.”
