Space and astronomy news
Cascades of spiraling magnetic loops observed in extreme ultraviolet light by Solar Dynamics Observatory danced and twisted above an active region on the Sun recently (April 3-5, 2011). These loops are charged particles spinning along the magnetic field lines. The bright active region was fairly strong and the activity persistent, though not explosive. At one point darker plasma can be seen being pulled back and forth across the region’s center.
Source: Solar Dynamics Observatory
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Recent modeling of Sun-like stars with planetary systems, found that a system with four rocky planets and four gas giants in stable orbits – and only a sparsely populated outer belt of planetesimals – has only a 15 to 25% likelihood of developing. While you might be skeptical about the validity of a model that puts our best known planetary system in the unlikely basket, there may be some truth in this finding.
This modeling has been informed by the current database of known exoplanets and otherwise based on some prima facie reasonable assumptions. Firstly, it is assumed that gas giants are unable to form within the frost line of a system – a line beyond which hydrogen compounds, like water, methane and ammonia would exist as ice. For our Solar System, this line is about 2.7 astronomical units from the Sun – which is roughly in the middle of the asteroid belt.
Gas giants are thought to only be able to form this far out as their formation requires a large volume of solid material (in the form of ices) which then become the cores of the gas giants. While there may be just as much rocky material like iron, nickel and silicon outside the frost line, these materials are not abundant enough to play a significant role in forming giant planets and any planetesimals they may form are either gobbled up by the giants or flung out of orbit.
However, within the frost line, rocky materials are the dominant basis for planet forming – since most light gas is blown out of the region by force of the stellar wind and other light compounds (such as H2O and CO2) are only sustained by accretion within forming planetesimals of heavier materials (such as iron, nickel and silicates). Appreciably-sized rocky planets would probably form in these regions within 10-100 million years after the star’s birth.
So, perhaps a little parochially, it is assumed that you start with a system of three regions – an inner terrestrial planet forming region, a gas giant forming region and an outer region of unbound planetesimals, where the star’s gravity is not sufficient to draw material in to engage in further accretion.
From this base, Raymond et al ran a set of 152 variations, from which a number of broad rules emerged. Firstly, it seems that the likelihood of sustaining terrestrial inner planets is very dependent on the stability of the gas giants’ orbits. Frequently, gravitational perturbations amongst the gas giants results in them adopting more eccentric elliptical orbits which then clears out all the terrestrial planets – or sends them crashing into the star. Only 40% of systems retained more than one terrestrial planet, 20% had just one and 40% had lost them all.
Debris disks of hot and cold dust were found to be common phenomena in matured systems which did retain terrestrial planets. In all systems, primal dust is largely cleared out within the first few hundred million years – by radiation or by planets. But, where terrestrial planets are retained, there is a replenishment of this dust – presumably via collisional grinding of rocky planetesimals.
This finding is reflected in the paper’s title Debris disks as signposts of terrestrial planet formation. If this modeling work is an accurate reflection of reality, then debris disks are common in systems with stable gas giants – and hence persisting terrestrial planets – but are absent from systems with highly eccentric gas giant orbits, where the terrestrial planets have been cleared out.
Nonetheless, the Solar System appears as unusual in this schema. It is proposed that perturbations within our gas giants’ orbits, leading to the Late Heavy Bombardment, were indeed late with respect to how other systems usually behave. This has left us with an unusually high number of terrestrial planets which had formed before the gas giant reconfiguration began. And the lateness of the event, after all the collisions which built the terrestrial planets were finished, cleared out most of the debris disk that might have been there – apart from that faint hint of Zodiacal light that you might notice in a dark sky after sunset or before dawn.
Further reading: Raymond et al Debris disks as signposts of terrestrial planet formation.
On April 12, 1961, Russian cosmonaut Yuri Gagarin (left, on the way to the launch pad) became the first human in space, making a 108-minute orbital flight in his Vostok 1 spacecraft.
Newspapers like The Huntsville Times (right) trumpeted Gagarin's accomplishment.
Credit: NASA
Send Ken your Yuri’s Night event reports and photos
Mark your calendars. April 12, 2011 marks the 50th Anniversary of Human Spaceflight and Cosmonaut Yuri Gagarin’s astonishing First Orbit of our precious planet Earth on April 12, 1961. Gagarin was the first human to enter outer space and see what no one else had ever witnessed – our commonly shared Earth as a planet and beautiful blue globe with no borders.
Space enthusiasts worldwide are celebrating this watershed moment in Human history at a network of over 400 “Yuri’s Night” parties taking place in more than 70 countries on 6 continents and 2 worlds, according to the official “Yuri’s Night” website.
Gagarin’s flight took place in the midst of the inflammatory Cold War rivalry between the Soviet Union and the United States and shocked the world into new realities. The Space Race led to the first lunar landing by the United States and Neil Armstrong’s first steps on the moons surface in 1969. Eventually, the world’s superpowers beat swords into plowshares and united their efforts to build the International Space Station.
Gagarin flew around the Earth in a single orbit at an altitude of 302 kilometers (187 miles). The flight lasted 108 minutes and safely ended when he descended back and parachuted to the ground, just north of the Caspian Sea. At the age of 27, Gagarin was instantly transformed into a worldwide hero. After the momentous flight he soon embarked on an international tour.
20 years later on April 12, 1981, NASA’s first space shuttle blasted off on the STS-1 mission on a daring test flight with astronauts John Young and Bob Crippen strapped inside Space Shuttle Columbia.
The first “Yuri’s Night – World Space Party” was held on April 12, 2001 to commemorate the 40th anniversary of Gagarin’s spaceflight. Over 10,000 people attended 64 events located worldwide. The goal was to inspire people, increase awareness and support for space exploration across the globe and foster the spread of new ideas to broaden our access to space.
“Yuri’s Night” has been growing in popularity every year. Events range in size from a few folks to numbers in the thousands. Attendees range from astronauts and cosmonauts, NASA and global space agency officials and reps, scientists and engineers, famous actors, playwrights, writers, artists, athletes and musicians to just everyday folks and kids of all ages and backgrounds. Everyone can get involved.
“First Orbit” recreates much of the view of the Earth’s surface that Gagarin would have seen fifty years ago. Mostly he flew over the world oceans as well as the Soviet Union and Africa.
Riley collaborated with the astronauts aboard the International Space Station, chiefly Paolo Nespoli of ESA, who took film footage from the new 7 windowed Cupola as the station matched the actual flight path of Gagarin and Vostok 1 as closely as possible. The free film celebrates 50 years of human spaceflight.
“First Orbit” premiers worldwide on YouTube in a special global streaming event for Yuri’s Night on April 12 . Watch the short trailer below, with original and stirring music by Philip Sheppard.
It’s easy and free to register your local party at the Yuri’s Night event website. There is still time to register your Yuri’s Night party – Indeed the list has grown as I typed out this story !
Some events are already set to kick off this weekend. I’ll be presenting at an interactive and free Yuri’s Night evening event in Princeton Junction, New Jersey, about Gagarin’s flight and my experiences with the space shuttle and what‘s beyond.
Send Ken your “Yuri’s Night” event photos/short report to post in a round up story at Universe Today about the global festivities celebrating the historic achievement of Yuri Gagarin. Email kremerken at yahoo dot com
First Orbit Trailer II
Read Ken’s other stories about Yuri Gagarin and Yuri’s Night:
Yuri Gagarin and Vostok 1 Photo Album – 50th Anniversary of Human Spaceflight
Stirring Video Tributes to Yuri Gagarin
Yuri’s Night Website
Yuri’s Night Party list
Yuri’s Night Party with Ken in Princeton Junction, NJ, USA
First Orbit Website
STS-1 NASA Mission Website
Ken Kremer
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The big question weighing on the minds of anyone involved or interested in US space exploration is how a US government shutdown would affect the space agency. In short, if a NASA job or service is curtailed or a department or building is closed and it doesn’t threaten a life, a spacecraft, data, or a mission, it won’t be continued during a government shutdown. That means thousands of NASA employees would be furloughed, scientists for robotic missions won’t be able to work on gathering new data, and the STS-134 launch could be delayed indefinitely until Congress passes a budget.
While the shuttle mission wouldn’t launch as scheduled on April 29 to the International Space Station because of a shutdown, all NASA workers essential to the ISS and its operations would continue to work, as well as those who keep the space shuttle Endeavour – out on the launchpad – safe and stable. Additionally, engineers involved with NASA’s many space probes and Earth orbiting satellites who monitor spacecraft health and keep them functioning – those “necessary to prevent harm to life or property” as NASA put it, would keep working. But scientists and researchers involved with those missions will likely be sent home.
In a letter to the Office of Management and Budget, NASA Chief Financial Officer Elizabeth Robinson provided an update on how NASA will function in the event of a government funding hiatus. “The decision on what personnel should be excepted from furlough is very fact specific, and Directors in charge of NASA Centers are in the best position to make detailed decisions regarding the suspension of ongoing, regular functions which could imminently threaten the safety of human life or the protection of property,” Robinson wrote.
For example, at NASA Headquarters, there are 1,611 total employees, and only 22 are considered “essential” and would not be furloughed. At NASA’s Ames Research Center, only 25 out of 1250 full time employees would not be furloughed if and when shutdown happens.
A government employee told us that during a furlough, even if someone is classified as “essential” or “exempted” and has to come in and work, they won’t get paid until later. For “non-essential” employees, there is no guarantee the government will provide any compensation for the time the government offices are is closed. “For the shutdown in 1995, they DID give everyone back pay,” said the employee, who wished to remain anonymous. “But this time? Who knows?”
For anyone who lives and breathes NASA on the internet, you will find your lifeblood cut. NASA TV will not broadcast. NASA websites will not be updated including the main nasa.gov site; the NASA Earth Observatory website sent out an email to notify subscribers that they will not be able to update starting April 9 if the shutdown occurs. This is for security reasons, since IT people won’t be there to maintain and secure the websites.
NASA employees, including astronauts who have “official” Twitter accounts have been ordered not to Tweet under a government shutdown and the same goes for Facebook updates for any official NASA account or mission. One exception is that ESA astronaut Paolo Nespoli on board the ISS can still use Twitter.
Any tours and public access to NASA Centers and facilities will be canceled, and any NASA instructors at schools or universities will be ordered not to report. A news conference scheduled for April 12 at the Kennedy Space Center to announce which museums will have won the rights to display NASA’s three space shuttles would has been put on hold pending the government shutdown.
These and other things will occur if no agreement is reached on a fiscal year 2011 budget by midnight tonight, (Friday, April 8, 2011). For more details, see this NASA page which includes three pdf documents which outline what happens for the space agency during a government shutdown. Without getting into the politics, the entire situation is very sad and disheartening.
Thanks to Heather Archuletta (Pillownaut) for the lead image.
If you want to find the planet Saturn in the sky this weekend, but aren’t sure where to look, this guide should help you.
Saturn is visible all night long at the moment and is quite easy to find, as it is just past opposition which makes it quite bright.
Find the constellation of Leo the Lion (high in the Southern sky at around 10pm) by looking for the backwards question mark asterism (red in the diagram), which is the head of Leo. Find the last 2 stars in Leo’s body and draw an imaginary line through these 2 stars, and arc to the left and down until you reach a bright yellowish star. This is Saturn.
If you continue drawing this imaginary line a little further you will find the bright bluish white star Spica, in the constellation of Virgo.
Right now, Saturn should be an easy target to spot with the naked eye, but looks great through binoculars and is truly amazing through any telescope.
For reasons yet unknown, the rate of midnight fireballs increases during the weeks around the vernal equinox. It’s a beautiful display, but where do they come from? Last month, we reported on a network of fireball cameras that NASA is building, which is now tracking incoming fireballs — and just in time, too, for the fireball season. This video is part of a new series by NASA called ScienceCast, which will be a weekly feature highlighting a topic in NASA science news.
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One of the successes of the ΛCDM model of the universe is the ability for models to create structures of with scales and distributions similar to those we view in the universe today. Or, at least that’s what astronomers tell us. While computer simulations can recreate numerical universes in a box, interpreting these mathematical approximations is a challenge in and of itself. To identify the components of the simulated space, astronomers have had to develop tools to search for structure. The results has been nearly 30 independent computer programs since 1974. Each promises to reveal the forming structure in the universe by finding regions in which dark matter halos form. To test these algorithms out, a conference was arranged in Madrid, Spain during the May of 2010 entitled “Haloes going MAD” in which 18 of these codes were put to the test to see how well they stacked up.
Numerical simulations for universes, like the famous Millennium Simulation begin with nothing more than “particles”. While these were undoubtedly small on a cosmological scale, such particles represent blobs of dark matter with millions or billions solar masses. As time is run forwards, they are allowed to interact with one another following rules that coincident with our best understanding of physics and the nature of such matter. This leads to an evolving universe from which astronomers must use the complicated codes to locate the conglomerations of dark matter inside which galaxies would form.
One of the main methods such programs use is to search for small overdensities and then grow a spherical shell around it until the density falls off to a negligible factor. Most will then prune the particles within the volume that are not gravitationally bound to make sure that the detection mechanism didn’t just seize on a brief, transient clustering that will fall apart in time. Other techniques involve searching other phase spaces for particles with similar velocities all nearby (a sign that they have become bound).
To compare how each of the algorithms fared, they were put through two tests. The first, involved a series of intentionally created dark matter halos with embedded sub-halos. Since the particle distribution was intentionally placed, the output from the programs should correctly find the center and size of the halos. The second test was a full fledged universe simulation. In this, the actual distribution wouldn’t be known, but the sheer size would allow different programs to be compared on the same data set to see how similarly they interpreted a common source.
In both tests, all the finders generally performed well. In the first test, there were some discrepancies based on how different programs defined the location of the halos. Some defined it as the peak in density, while others defined it as a center of mass. When searching for sub-halos, ones that used the phase space approach seemed to be able to more reliably detect smaller formations, yet did not always detect which particles in the clump were actually bound. For the full simulation, all algorithms agreed exceptionally well. Due to the nature of the simulation, small scales weren’t well represented so the understanding of how each detect these structures was limited.
The combination of these tests did not favor one particular algorithm or method over any other. It revealed that each generally functions well with regard to one another. The ability for so many independent codes, with independent methods means that the findings are extremely robust. The knowledge they pass on about how our understanding of the universe evolves allows astronomers to make fundamental comparisons to the observable universe in order to test the such models and theories.
The results of this test have been compiled into a paper that is slated for publication in an upcoming issue of the Monthly Notices of the Royal Astronomical Society.
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NASA’s massive ‘Curiosity’ rover is almost ready to begin the first leg of its long trek to the surface of the Red Planet. Engineers at NASA’s Jet Propulsion Laboratory in California are nearly finished with assembling and testing all the components of the Mars Science Laboratory (MSL) mission (see photos above and below).
The MSL team plans to ship Curiosity as well as the cruise stage, descent stage and back shell to the Kennedy Space Center (KSC) in May and June. After arriving at KSC, all the pieces will be integrated together and tested during final assembly in a clean room. The rover will then be installed inside a 5 meter diameter nose cone, shipped the short distance to Cape Canaveral and then bolted atop an Atlas V rocket (photo below).
The launch window for Curiosity extends from Nov. 25 to Dec. 18, 2011. The first stage of the powerful Atlas V rocket will be augmented with four solid rocket boosters. The Atlas V has previously launched two planetary missions; the Mars Reconnaissance Orbiter (MRO) and the New Horizons mission to Pluto.
Take a long gander at the 3 meter long rover because its appearance is now very much how it will look while it’s roving along intriguing martian landscapes for at least two earth years after landing in August 2012.
The mini-Cooper sized Curiosity rover is equipped with 10 science instruments to investigate Martian soil and rock samples in far greater detail than ever before. Curiosity’s science payload weighs ten times more than any prior Mars rover mission.
The goal is to search for clues to environmental conditions favorable for microbial life and for preserving evidence about whether Martian life ever existed in the past or today. NASA is scrutinizing a list of four potential landing sites for the best chance of finding a habitable zone.
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A 2001 space odyssey indeed! On this day in 2001, the Mars Odyssey spacecraft launched, and now, 3,333 days later, the robotic spacecraft is still going strong. In orbit around the Red Planet, Mars Odyssey has collected more than 130,000 images and continues to send information to Earth about Martian geology, climate, and mineralogy. Last December, Mars Odyssey broke the record for the longest-serving spacecraft at Mars, besting the Mars Global Surveyor, which operated in orbit of Mars from 1997 to 2006.
Measurements by Odyssey have enabled scientists to create maps of minerals and chemical elements and identify regions with buried water ice. Images that measure the surface temperature have provided spectacular views of Martian topography.
Early in the mission, Odyssey determined that radiation in low-Mars orbit is twice that in low-Earth orbit. This is an essential piece of information for eventual human exploration because of its potential health effects — Odyssey has provided vital support to ongoing exploration of Mars by relaying data from the Mars rovers to Earth via the spacecraft’s UHF antenna.
Odyssey will support the 2012 landing of the Mars Science Laboratory and surface operations of that mission. Mars Science Laboratory, a.k.a Curiosity, will assess whether its landing area has had environmental conditions favorable for microbial life and preserving evidence about whether life has existed there. The rover will carry the largest, most advanced set of instruments for scientific studies ever sent to the Martian surface.
Mars Odyssey carries three main science instruments: The Gamma Ray Spectrometer (GRS), the Thermal Emission Imaging System (THEMIS), and the Mars Radiation Environment Experiment (MARIE).
More info: Mars Odyssey website, THEMIS website (tons of great images)
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In 2009, hundreds of thousands of people participated in one way or another with the International Year of Astronomy, and there’s no reason to let the excitement die! Astronomers Without Borders are celebrating the entire month of April as Global Astronomy Month and one of the focus points is just three days from arrival… Global Lunar Week!
” A week-long series of programs, from April 10 through 16, will be dedicated to the Moon during Global Astronomy Month to help people rediscover our closest companion in space.” says AWB. “Lunar Week takes place while the Moon is well-placed for observation in the evening sky. As the Moon’s phases and positions change during its orbit around the Earth, there will be Moon-themed star parties to observe the Moon by telescope and naked eye, educational programs, online observing events, competitions and a celebration of the Moon in different cultures.”
Astronomers Without Borders has a theme – One People * One Sky. For all of those who read Universe Today, we realize quickly how astonomy can bring together friends from different countries, different cultures and different time zones. Wouldn’t it be wonderful if we could all observe together?
The dream can come true…
Sander Klieverik from AstronomyLive is working with telescopes around the world to celebrate Global Lunar Week and bring the view right to you.
“The week will start with an amazing broadcast from the historic Chamberlin observatory of the Denver university (with the help of Prof. R. Stencel). It will start april 9th between 7-10pm local time (Denver), which is 01-04 GMT April 10th.” says Sander. “Our goal is to get as many telescopes pointed towards the Moon as possible. I hope that there will be a continuous view of the Moon somewhere from the globe the whole week.”
How can you participate? It’s easy! Just tune into the AstronomyLive Website and follow the instructions. “During the Lunar Week, AstronomyLive will host at least two broadcasts, currently scheduled 15th and 16th of April.” instructs Klieverik. “The first broadcast will take you on a journey across the 85% illuminated lunar surface, on the hunt for the most beautiful craters during this phase, the ´Crater hunt´. The craters at the terminator will receive special attention, the dark side of the moon that changes during the Moon phase. Please know that you will see a LIVE view of the Moon and not some Moon photo. The same accounts for the “Apollo Hop”.
Come one, come all… Lunatics are welcome!