Mponda Malazo from Tanzania who works with Astronomers Without Borders, teaches students about solar dynamics. Another solar viewing telescope with a sun-funnel will be on its way to Tanzania soon. Credit: Astronomers Without Borders.
The international astronomy outreach group Astronomers Without Borders has launched a major crowdfunding campaign on Indiegogo, and they need your help. They are looking to raise $38,000 to fund a science center and observatory in East Africa to bring quality science education to the children of the area.
“It will be a game-changer for the region and a big project demonstrating the importance of astronomy education, including new curricula for teaching astronomy, teacher training, and more,” Mike Simmons, President and founder of AWB told Universe Today.
Simmons said Tanzanian students are often without textbooks and many basic educational resources and teacher training in science is often lacking.
“Providing the opportunity for people to get involved in this important project in East Africa is a perfect fit for Astronomers Without Borders’ motto, ‘One People, One Sky,'” he said.
After three years of making a difference in Tanzania by providing telescopes and teacher resources for schools, this new campaign goes even further, helping to provide a sustainable vision for the future and a pathway to success for the country’s youth.
Graph via Astronomer Without Borders.
The Center for Science Education and Observatory will provide astronomical and science training for both teachers and students. AWB said in a press release that by integrating astronomy into the national teaching curriculum, the center will be able to develop and circulate hands-on science and astronomy teaching resources to schools around the country. The center will also house hands-on laboratories, and an astronomical observatory with a portable planetarium, and internet connectivity so that connections can be made with science centers worldwide.
“We’re excited to be taking the next step in making this unique and innovative project a sustainable reality,” said Simmons. “The need is great and a lot has already been accomplished.”
To learn more about supporting The Center for Science Education and Observatory and Telescopes to Tanzania visit the Indiegogo campaign page at
Frame grab from a Youtube video of the brilliant meteor that flared over Australia overnight.
“It first looked like a plane with fire coming out of the tail.”— Aaron O.
“I have never seen anything like it. Big, bright and moving gently across sky – slower than a plane, not falling at all but moving across.” — Shannon H.
“Viewed from cockpit of aircraft at 37,000′. Was visible for two or three minutes.”— Landy T.
Flaming plane? Incandescent visitor from the asteroid belt? As the these comments from the AMS Fireball Log attest, the brilliant and s-l-o-w fireball that seared the sky over southeastern Australia tonight was probably one of the most spectacular displays of re-entering space junk witnessed in recent years.
Ted Molczan, citizen satellite tracker and frequent contributor to the amateur satellite watchers SeeSat-L site, notes that the timing and appearance almost certainly point to the decay or de-orbiting of the Russian Soyuz 2-1B rocket booster that launched the meteorological satellite Meteor M2 on July 8.
Meteor over New South Wales. Look closely near the end and you’ll see it disintegrate into small pieces.
The magnificent man-made meteor, weighing some 4,400 pounds (2,000 kg), was seen from Melbourne to Sydney across the states of Victoria and New South Wales around 10 p.m. Hundreds of people were stopped in their tracks. Most noticed how slowly the fireball traveled and how long it continue to burn on the way down.
Spacecraft that reenter from either orbital decay or controlled entry usually break up at altitudes between 45-52 miles (84-72 km) traveling around 17,500 mph (28,000 km/hour) . Compression and friction from the ever-thickening air cause the craft, or in this case, the rocket booster, to slow down and heat up to flaming incandescence just like a hunk of space rock arriving from the asteroid belt. In both cases, we see a brilliant meteor, however manmade debris.
A Delta 2 third stage, known as a PAM-D, reentered the atmosphere over the Middle East on Jan. 21, 2001. The titanium motor casing, weighing about 154 lbs. (70 kg), landed in Saudi Arabia about 150 miles from the capital of Riyadh. Credit: NASA, Orbital Debris Program Office
Occasional meteoroids break apart in the atmosphere and scatter meteorites just as pieces of occasional satellites, especially large, heavy craft, can survive the plunge and land intact – if a tad toasted. Whether anything remains of Russian rocket stage or where exactly it fell is still unknown. Here are a few more photos of successful space junk arrivals.
The only person to be hit by manmade space debris was Lottie Williams in 1997. She was unharmed. Credit: Tulsa World
Reportedly, only one person has been struck by satellite debris. In 1997 Lottie Williams of Tulsa, Oklahoma was hit on the shoulder while walking by a small, twisted piece of metal weighing as much as a crushed soda can. It was traced back to the tank of a Delta II rocket that launched a satellite in 1996. I suppose it’s only a matter of time before someone else gets hit, but the odds aren’t great. More likely, you’ll see what alarmed and delighted so many southeastern Australians Thursday night: a grand show of disintegration.
This artist’s view shows an extrasolar planet orbiting a star (the white spot in the right). Image Credit: IAU/M. Kornmesser/N. Risinger (skysurvey.org)
It’s the latest chapter in a years-long controversy over how celestial objects, including exoplanets, are classified and named.
Although the IAU has presided over the long process of naming astronomical objects for nearly a century, until last year they didn’t feel the need to include exoplanets on this long list.
As late as March 2013, the IAU’s official word on naming exoplanets was: “The IAU sees no need and has no plan to assign names to these objects at the present stage of our knowledge.” Since there was seemingly going to be so many exoplanets, the IAU saw it too difficult to name them all.
Other organizations, however, such as the SETI institute and the space company Uwingu leapt at the opportunity to engage the public in providing names for exoplanets. Their endeavors have been widely popular with the general public, but generated discussion about how ‘official’ the names would be.
The IAU issued a later statement in April 2014 (which Universe Today covered with vigor) and claimed that these two campaigns had no bearing on the official naming process. By August 2014, the IAU had introduced new rules for naming exoplanets, drastically changing their stance and surprising many.
Now in partnership with Zooniverse, a citizen-science organization, the IAU has drawn up a list of 305 well-characterized exoplanets in 206 solar systems. Starting in September, astronomy organizations can register for the opportunity to select planets for naming.
In October, the IAU plans to ask the registered organizations to vote for the 20 to 30 worlds on the list that they want to name. The exact number will depend on the number of registered groups. In December, those groups can propose names for the worlds that get the most votes. Groups can only propose names in accordance with the following set of rules. A name must be:
— 16 characters or less in length
— Preferably one word
— Pronounceable (in some language)
— Non-offensive
— Not too similar to an existing name of an astronomical object
Starting in March 2015, the list of proposed names will be put up to an Internet vote. The winners will be validated by the IAU, and announced during a ceremony at the IAU General Assembly in Honolulu in August 2015.
The popular name for a given exoplanet won’t replace the scientific name. But it will carry the IAU seal of approval.
Astronomer Alan Stern, principal investigator of the New Horizons mission to Pluto and CEO of Uwingu told Universe Today’s Senior Editor, Nancy Atkinson, that he was not surprised by the IAU’s new statement. “To my eye though, it’s just more IAU elitism, they can’t seem to get out of their elitist rut thinking they own the Universe.”
“Uwingu’s model is in our view far superior — people can directly name planets around other stars, with no one having to approve the choices,” Stern continued. “With 100 billion plus planets in the galaxy, why bother with committees of elites telling people what they do and don’t approve of?”
If nothing else, the controversy has sparked multiple venues to name exoplanets and more importantly learn about these alien worlds.
A map of cosmic ray concentrations in the northern sky, showing a "hotspot" (red) in the location of the Big Dipper. Credit: K. Kawata, University of Tokyo Institute for Cosmic Ray Research
Behind the Big Dipper is something pumping out a lot of extremely high-energy cosmic rays, a new study says. And as astronomers try to learn more about the nature of these emanations — maybe black holes, maybe supernovas — newer work hints that it could be related to how the universe is structured.
It appears that the particles come from spots in the cosmos where matter is densely packed, such as in “superclusters” of galaxies, the researchers stated, adding this is promising progress for tracking down the source of the cosmic rays.
“This puts us closer to finding out the sources – but no cigar yet,” stated University of Utah physicist Gordon Thomson, co-principal investigator for the Telescope Array that performed the observations. “All we see is a blob in the sky, and inside this blob there is all sorts of stuff – various types of objects – that could be the source,” he added. “Now we know where to look.”
The study examined the highest-energy cosmic rays that are about 57 billion billion electron volts (5.7 times 10 to the 19th power), picking that type because it is the least affected by magnetic field lines in space. As cosmic rays interact with the magnetic field lines, it changes their direction and thus makes it harder for researchers to figure out where they came from.
Ursa Major and Big Dipper Among the Red Clouds. Credit: Rajat Sahu
Scientists used a set of 500 detectors called the Telescope Array, which is densely packed in a 3/4 mile (1.2 kilometer) square grid in the desert area of Millard County, Utah. The array recorded 72 cosmic rays between May 11, 2008 and May 4, 2013, with 19 of those coming from the “hotspot” — a circle 40 degrees in diameter taking up 6% of the sky. (Researchers are hoping for funding for an expansion to probe this area in more detail.)
It’s possible the hotspot could be a fluke, but not very possible, the researchers added: there’s a 1.4 in 10,000 chance. And they’re keeping themselves open to many types of sources: “Besides active galactic nuclei and gamma ray emitters, possible sources include noisy radio galaxies, shock waves from colliding galaxies and even some exotic hypothetical sources such as the decay of so-called ‘cosmic strings’ or of massive particles left over from the big bang that formed the universe 13.8 billion years ago,” the researchers stated.
Cosmic rays were first discovered in 1912 and are believed to be hydrogen nuclei or the centers of nuclei from heavier elements like iron or oxygen. The highest-energy ones in the study may come from protons alone, but that’s not clear yet.
An artist's conception of a supermassive black hole's jets. Credit: NASA / Dana Berry / SkyWorks Digital
The supermassive black holes in the cores of most massive galaxies wreak havoc on their immediate surroundings. During their most active phases — when they ignite as luminous quasars — they launch extremely powerful and high-velocity outflows of gas.
These outflows can sweep up and heat material, playing a pivotal role in the formation and evolution of massive galaxies. Not only have astronomers observed them across the visible Universe, they also play a key ingredient in theoretical models.
But the physical nature of the outflows themselves has been a longstanding mystery. What physical mechanism causes gas to reach such high speeds, and in some cases be expelled from the galaxy?
A new study provides the first direct evidence that these outflows are accelerated by energetic jets produced by the supermassive black hole.
Using the Very Large Telescope in Chile, a team of astronomers led by Clive Tadhunter from Sheffield University, observed the nearby active galaxy IC 5063. At locations in the galaxy where its jets are impacting regions of dense gas, the gas is moving at extraordinary speeds of over 600,000 miles per hour.
“Much of the gas in the outflows is in the form of molecular hydrogen, which is fragile in the sense that it is destroyed at relatively low energies,” said Tadhunter in a press release. “I find it extraordinary that the molecular gas can survive being accelerated by jets of highly energetic particles moving at close to the speed of light.
As the jets travel through the galactic matter, they disrupt the surrounding gas and generate shock waves. These shock waves not only accelerate the gas, but also heat it. The team estimates the shock waves heat the gas to temperatures high enough to ionize the gas and dissociate the molecules. Molecular hydrogen is only formed in the significantly cooler post-shock gas.
“We suspected that the molecules must have been able to reform after the gas had been completely upset by the interaction with a fast plasma jet,” said Raffaella Morganti from the Kapteyn Institute Groningen University. “Our direct observations of the phenomenon have confirmed that this extreme situation can indeed occur. Now we need to work at describing the exact physics of the interaction.”
In interstellar space, molecular hydrogen forms on the surface of dust grains. But in this scenario, the dust is likely to have been destroyed in the intense shock waves. While it is possible for molecular hydrogen to form without the aid of dust grains (as seen in the early Universe) the exact mechanism in this case is still unknown.
The research helps answer a longstanding question — providing the first direct evidence that jets accelerate the molecular outflows seen in active galaxies — and asks new ones.
A portion of a 2014 Mars map showing the area east of Hellas basin, at midsoutherly latitudes. Credit: USGS
Where did the water on Mars come from, and where did it go? This plot (sort of) formed the basis of one of the best Doctor Who episodes of the modern era, but in all seriousness, it is also driving scientists to examine the Red Planet over and over again.
This means revisiting older information with newer data to see if everything still matches up. From time to time, it doesn’t. The latest example came when scientists at the U.S. Geological Survey created a map of the canyon systems of Waikato Vallis and Reull Vallis, which are in the midsoutherly latitudes of Mars.
They previously believed the canyons were connected, but updating the data from an understanding based on 1980s Viking data revealed a different story.
“These canyons are believed to have formed when underground water was released from plains materials to the surface, causing the ground to collapse. The water could have been stored within the plains in localized aquifers or as ice, which could have melted due to the heat from nearby volcanoes,” the U.S. Geological Survey stated.
Part of the floor of Reull Vallis, a valley east of Hellas Basin on Mars. Picture taken by Mars Global Surveyor. Credit: NASA/JPL/Malin Space Science Systems
But the newer data — looking at information from the Mars Reconnaissance Orbiter, Mars Odyssey, Mars Global Surveyor — revealed the canyons are quite separate, demarcated by a zone called Eridania Planitia in between.
“Careful estimates of the ages of the canyons and the plains reveal a sequence of events starting with the water released from Waikato Vallis, which would have been stored for a time in the plains as a shallow lake. As Reull Vallis was forming separately, the canyon breached a crater rim that was holding back the water in the lake; the lake drained gradually, which can be seen by many smaller channels incised on the floor of Reull Vallis.”
The map was co-produced by Scott Mest and David Crown, who are both of the Planetary Science Institute. You can view the entire map and related materials here.
The Milky Way as seen from Devil's Tower, Wyoming. Image Credit: Wally Pacholka
There are few moments more breathtaking than standing beneath a brilliant starry sky. Thousands of small specks of light mark only the beginning of the vast cosmic arena, with its unimaginable vistas of time and space. The Milky Way, wrapping above in a cosmic sheet of colors and patterns, also hints that there’s more than meets the eye.
Most of us long for these dark nights, far away from the city lights. But a new study suggests the Universe is a little too dark.
The vast reaches of empty space are bridged by filaments of hydrogen and helium. But there’s a disconnect between how bright the large-scale structure of the Universe is expected to be and how bright it actually is.
In a recent study, a team of astronomers led by Juna Kollmeier from the Carnegie Institute for Science found the light from known populations of stars and quasars is not nearly enough to explain observations of intergalactic hydrogen.
In a brightly lit Universe, intergalactic hydrogen will be easily destroyed by energetic photons, meaning images of the large-scale structure will actually appear dimmer. Whereas in a dim Universe, there are fewer photons to destroy the intergalactic hydrogen and images will appear brighter.
Hubble Space Telescope observations of the large-scale structure show a brightly lit Universe. But supercomputer simulations using only the known sources of ultraviolet light produces a dimly lit Universe. The difference is a stunning 400 percent.
Computer simulations of intergalactic hydrogen in a “dimly lit” universe (left) and a “brightly lit” universe (right) that has five times more of the energetic photons that destroy neutral hydrogen atoms. Image Credit: Ben Oppenheimer / Juna Kollmeier.
Observations indicate that the ionizing photons from hot, young stars are almost always absorbed by gas in the host galaxy, so they never escape to affect intergalactic hydrogen. The necessary culprit could be the known number of quasars, which is far lower than needed to produce the required light.
“Either our accounting of the light from galaxies and quasars is very far off, or there’s some other major source of ionizing photons that we’ve never recognized,” said Kollmeier in a press release. “We are calling this missing light the photon underproduction crisis. But it’s the astronomers who are in crisis — somehow or other, the universe is getting along just fine.”
Strangely, this mismatch only appears in the nearby, relatively well-studied cosmos. In the early Universe, everything adds up.
“The simulations fit the data beautifully in the early universe, and they fit the local data beautifully if we’re allowed to assume that this extra light is really there,” said coauthor Ben Oppenheimer from the University of Colorado. “It’s possible the simulations do not reflect reality, which by itself would be a surprise, because intergalactic hydrogen is the component of the Universe that we think we understand the best.”
So astronomers are attempting to shed light on the missing light.
“The most exciting possibility is that the missing photons are coming from some exotic new source, not galaxies or quasars at all,” said coauthor Neal Katz from the University of Massachusetts at Amherst.
The team is exploring these new sources with vigor. It’s possible that there could be an undiscovered population of quasars in the nearby Universe. Or more exotically, the photons could be created from annihilating dark matter.
“The great thing about a 400 percent discrepancy is that you know something is really wrong,” said coauthor David Weinberg from Ohio State University. “We still don’t know for sure what it is, but at least one thing we thought we knew about the present day universe isn’t true.”
The results were published in The Astrophysical Journal Letters and are available online.
The perigee Full Moon of June 22nd, 2013. Credit: Russell Bateman (@RussellBateman1)
‘Tis the season once again, when rogue Full Moons nearing perigee seem roam the summer skies to the breathless exhortations of many an astronomical neophyte at will. We know… by now, you’d think that there’d be nothing new under the Sun (or in this case, the Moon) to write about the closest Full Moons of the year.
But love ‘em or hate ‘em, tales of the “Supermoon” will soon be gracing ye ole internet again, with hyperbole that’s usually reserved for comets, meteor showers, and celeb debauchery, all promising the “biggest Full Moon EVER…” just like last year, and the year be for that, and the year before that…
How did this come to be?
What’s happening this summer: First, here’s the lowdown on what’s coming up. The closest Full Moon of 2014 occurs next month on August 10th at 18:11 Universal Time (UT) or 1:44 PM EDT. On that date, the Moon reaches perigee or its closest approach to the Earth at 356,896 kilometres distant at 17:44, less than an hour from Full. Of course, the Moon reaches perigee nearly as close once everyanomalistic month (the time from perigee-to-perigee) of 27.55 days and passes Full phase once every synodic period (the period from like phase to phase) with a long term average of 29.53 days.
Moon rise on the evening of July 11th, 2014 as seen from latitude 30 degrees north. Credit: Stellarium.
And the August perigee of the Moon only beats out the January 1st, 2014 perigee out by a scant 25 kilometres for the title of the closest perigee of the year, although the Moon was at New phase on that date, with lots less fanfare and hoopla for that one. Perigee itself can vary from 356,400 to 370,400 kilometres distant.
But there’s more. If you consider a “Supermoon” as a Full Moon falling within 24 hours of perigee, (folks like to play fast and loose with the informal definitions when the Supermoon rolls around, as you’ll see) then we actually have a trio of Supermoons on tap for 2014, with one this week on July 12th and September 9th as well.
What, then, is this lunacy?
Well, as many an informative and helpful commenter from previous years has mentioned, the term Supermoon was actually coined by an astrologer. Yes, I know… the same precession-denialists that gave us such eyebrow raising terms as “occultation,” “trine” and the like. Don’t get us started. The term “Supermoon” is a more modern pop culture creation that first appeared in a 1979 astrology publication, and the name stuck. A more accurate astronomical term for a “Supermoon” is a perigee-syzygy Full Moon or Proxigean Moon, but those just don’t seem to be able to “fill the seats” when it comes to internet hype.
One of the more arcane aspects set forth by the 1979 definition of a Supermoon is its curiously indistinct description as a “Full Moon which occurs with the Moon at or near (within 90% of) its closest approach to Earth in a given orbit.” This is a strange demarcation, as it’s pretty vague as to the span of distance (perigee varies, due to the drag of the Sun on the Moon’s orbit in what’s known as the precession of the line of apsides) and time. The Moon and all celestial bodies move faster near perigee than apogee as per Kepler’s 2nd Law of planetary motion.
A photo essay comparing Full Moon sizes and appearance from one Supermoon to the next, spanning 2011-2012. Credit: Marion Haligowski/RadicalRetinscopy. Used with permission.
We very much prefer to think of a Proxigean Moon as defined by a “Full Moon within 24 hours of perigee”. There. Simple. Done.
And let’s not forget, Full phase is but an instant in time when the Moon passes an ecliptic longitude of 180 degrees opposite from the Sun. The Moon actually never reaches 100% illumination due to its 5.1 degree tilt to the ecliptic, as when it does fall exactly opposite to the Sun it also passes into the Earth’s shadow for a total lunar eclipse.
-Check out this animation of the changing size of the Moon and its tilt — known as libration and nutation, respectively — as seen from our Earthly perspective over the span of one lunation.
The truth is, the Moon does vary from 356,400 to 406,700 kilometres in its wonderfully complicated orbit about our fair world, and a discerning eye can tell the difference in its size from one lunation to the next. This means the apparent size of the Moon can vary from 29.3’ to 34.1’ — a difference of almost 5’ — from perigee to apogee. And that’s not taking into account the rising “Moon illusion,” which is actually a variation of an optical effect known as the Ponzo Illusion. And besides, the Moon is actually more distant when its on the local horizon than overhead, to the tune of about one Earth radius.
Like its bizarro cousin the “minimoon” and the Blue Moon (not the beer), the Supermoon will probably now forever be part of the informal astronomical lexicon. And just like recent years before 2014, astronomers will soon receive gushing platitudes during next month’s Full Moon from friends/relatives/random people on Twitter about how this was “the biggest Full Moon ever!!!”
The perigee Full Moon of May 5th, 2012. Credit: Stephen Rahn (@StephenRahn13)
Does the summer trio of Full Moons look bigger to you than any other time of year? It will be tough to tell the difference visually over the next three Full Moons. Perhaps a capture of the July, August and September Full Moons might just tease out the very slight difference between the three.
And for those preferring not to buy in to the annual Supermoon hype, the names for the July, August and September Full Moons are the Buck, Sturgeon and Corn Moon, respectively. And of course, the September Full Moon near the Equinox is also popularly known as the Harvest Moon.
And in case you’re wondering, or just looking to mark your calendar for the next annual “largest Full Moon(s) of all time,” here’s our nifty table of Supermoons through 2020, as reckoned by our handy definition of a Full Moon falling within 24 hours of perigee.
So what do you say? Let ‘em come for the hype, and stay for the science. Let’s take back the Supermoon.
“Saw a beautiful Southern Light last night. I so wish you could see this with your own eyes!” Image taken from the International Space Station (ISS) on 5 July 2014. Credit: ESA/Alexander Gerst
Spectacular snapshots of the Southern Lights, Shooting Stars, the Sahara Desert and much more are streaming back from space to Earth courtesy of Alexander Gerst, ESA’s German astronaut currently serving aboard the International Space Station (ISS).
See a gallery of Alex’s stunning space-based views (sagenhafte Weltraum bilder) collected herein – starting with the auroral fireworks seen from space – above. It coincides with the Earth-based fireworks of America’s 4th of July Independence Day weekend celebrations and spectacular Noctilucent Clouds (NLCs) wafting over the Northern Hemisphere. NLC gallery here.
“Saw a beautiful Southern Light last night. I so wish you could see this with your own eyes!” Alex tweeted in English.
Gerst is posting his Earth & space imagery from the ISS on a variety of social media including Twitter, Facebook, Google+ and his ESA astronaut blog bilingually in English and German.
Another new snapshot of Earth’s “beautiful Southern Lights” taken from the ISS on 5 July 2014. Credit: ESA/Alexander Gerst
“Habe gestern ein wunderschönes Südlicht gesehen. Ich wünschte ihr könntet das mit eigenen Augen sehen!” Alex tweeted in German.
Check out Alexander Gerst’s stunning 1st timelapse video from the ISS:
Video Caption: ESA astronaut Alexander Gerst’s first timelapse from the International Space Station features the first shooting star that he saw from above. Made by stitching together over 250 images this short clip shows the beauty of our world and the space around it. Published on July 5, 2014. Credit: ESA/Alexander Gerst
Gerst launched to the ISS on his rookie space flight on May 28, 2014 aboard a Russian Soyuz capsule along with Russian cosmonaut Maxim Suraev and NASA astronaut Reid Wiseman.
ISS Expedition 40 patch
The trio are members of Expeditions 40 and 41 and joined three more station flyers already aboard – cosmonauts Alexander Skvortsov & Oleg Artemyev and astronaut Steve Swanson – to bring the station crew complement to six.
Alex will spend six months on the ISS for ESA’s Blue Dot mission. He is Germany’s third astronaut to visit the ISS. He is trained as a geophysicist and a volcanologist.
Gerst also has practiced and honed another talent – space barber! He shaved the heads of his two American crew mates – to match his bald head – after winning a friendly wager with them when Germany beat the US in a 2014 FIFA World Cup match on June 26.
Here’s several of Alexander Gerst’s newest views of the Sahara Desert and more.
“Even from space, the Sahara looks dry! Sogar vom Weltraum aus, sieht die Sahara trocken aus!” Taken from the ISS on 6 July 2014. Credit: ESA/Alexander Gerst“Harsh land. Windswept valleys in northern Africa. Hartes Land. Windgefraeste Taeler in Nordafrika.” Taken from the ISS on 6 July 2014. Credit: ESA/Alexander Gerst“Sometimes our atmosphere looks incredibly complex and three-dimensional, sometimes you don’t even see it. Manchmal schaut unsere Atmosphäre unglaublich Komplex und dreidimensional aus, manchmal fast unsichtbar.” Taken from the ISS on 5 July 2014. Credit: ESA/Alexander GerstAntarctic aurora. The Antarctic aurora, photographed by ESA astronaut Alexander Gerst and posted on social media with the comment: “Antarctic Aurora fleeing from sunrise. I have rarely seen something more magical in my life!” Credits: ESA/NASA/Alexander Gerst
Stay tuned here for Ken’s continuing ISS, OCO-2, GPM, Curiosity, Opportunity, Orion, SpaceX, Boeing, Orbital Sciences, MAVEN, MOM, Mars and more Earth & Planetary science and human spaceflight news.
Learn more about Orbital Sciences Antares ISS launch on July 11 from NASA Wallops, VA, and more about SpaceX, Boeing, commercial space, NASA’s Mars missions and more at Ken’s upcoming presentations.
July 10/11: “Antares/Cygnus ISS Launch from Virginia” & “Space mission updates”; Rodeway Inn, Chincoteague, VA, evening
Precisely dating a star can have important consequences for understanding stellar evolution and any circling exoplanets. But it’s one of the toughest plights in astronomy with only a few existing techniques.
One method is to find a star with radioactive elements like uranium and thorium, whose half-lives are known and can be used to date the star with certainty. But only about 5 percent of stars are thought to have such a chemical signature.
Another method is to look for a relationship between a star’s age and its ‘metals,’ the astronomer’s slang term for all elements heavier than helium. Throughout cosmic history, the cycle of star birth and death has steadily produced and dispersed more heavy elements leading to new generations of stars that are more heavily seeded with metals than the generation before. But the uncertainties here are huge.
The latest research is providing a new technique, showing that protostars can easily be dated by measuring the acoustic vibrations — sound waves — they emit.
Stars are born deep inside giant molecular clouds of gas. Turbulence within these clouds gives rise to pockets of gas and dust with enough mass to collapse under their own gravitational contraction. As each cloud — protostar — continues to collapse, the core gets hotter, until the temperature is sufficient enough to begin nuclear fusion, and a full-blown star is born.
Our Sun likely required about 50 million years to mature from the beginning of collapse.
Theoretical physicists have long posited that protostars vibrate differently than stars. Now, Konstanze Zwintz from KU Leuven’s Institute for Astronomy, and colleagues have tested this prediction.
The team studied the vibrations of 34 protostars in NGC 2264, all of which are less than 10 million years old. They used the Canadian MOST satellite, the European CoRoT satellite, and ground-based facilities such as the European Southern Observatory in Chile.
“Our data show that the youngest stars vibrate slower while the stars nearer to adulthood vibrate faster,” said Zwintz in a press release. “A star’s mass has a major impact on its development: stars with a smaller mass evolve slower. Heavy stars grow faster and age more quickly.”
Each stars’ vibrations are indirectly seen by their subtle changes in brightness. Bubbles of hot, bright gas rise to the star’s surface and then cool, dim, and sink in a convective loop. This overturn causes small changes in the star’s brightness, revealing hidden information about the sound waves deep within.
You can actually hear this process when the stellar light curves are converted into sound waves. Below is a video of such singing stars, produced by Nature last year.
“We now have a model that more precisely measures the age of young stars,” said Zwintz. “And we are now also able to subdivide young stars according to their various life phases.”
