All galaxies are going through some rate of star formation. New stars are being formed every year in the Milky Way. But some galaxies, classified as “starburst galaxies” are undergoing furious rates of star formation. Some are so active, they’re forming thousands of new stars every year.
So why do starburst galaxies form, when our own Milky Way has a relatively slow rate of new star formation? The most popular theory is that a galaxy is put into a starburst phase when it makes a close encounter with another galaxy. The gravitational interaction sends shockwaves through giant clouds of gas, causing them to collapse and form star forming regions. These create some of the most massive stars in the Universe; monster blue stars with more than 100 solar masses.
These massive stars live short lives and detonate as supernovae, blasting out more shockwaves into the galaxy. This creates a chain reaction that cascades through the galaxy. Within a few million years, the galaxy is forming stars at tens or even hundreds of times the rate of formation in a normal galaxy. And then when the gas is used up, within about 10 million years, the period of star formation ends.
Starburst galaxies are rare today, but astronomers have found that they were very common in the early Universe, when galaxies were closer and interacted more.
Thousands of starburst galaxies have been discovered across the Universe. One of the best known starburst galaxies is M82, located about 12 million light-years away in the constellation Ursa Major. The Hubble Space Telescope imaged the galaxy in 2005, and found 197 massive clusters of star formation going off simultaneously in the starburst core. The changes in M82 are being driven by its gravitationally interaction with nearby M81 galaxy.
We have written many articles about galaxies for Universe Today. Here’s an article about the starburst galaxy M82.
In 1971 physicist Stephen Hawking suggested that there might be “mini” black holes all around us that were created by the Big Bang. The violence of the rapid expansion following the beginning of the Universe could have squeezed concentrations of matter to form miniscule black holes, so small they can’t even be seen in a regular microscope. But what if these mini black holes were everywhere, and in fact, what if they make up the fabric of the universe? A new paper from two researchers in California proposes this idea.
Black holes are regions of space where gravity is so strong that not even light can escape, and are usually thought of as large areas of space, such as the supermassive black holes at the center of galaxies. No observational evidence of mini-black holes exists but, in principle, they could be present throughout the Universe.
Since black holes have gravity, they also have mass. But with mini black holes, the gravity would be weak. However, many physicists have assumed that even on the tiniest scale, the Planck scale, gravity regains its strength.
Experiments at the Large Hadron Collider are aimed at detecting mini black holes, but suffer from not knowing exactly how a reduced-Planck-mass black hole would behave, say Donald Coyne from UC Santa Cruz (now deceased) and D. C. Cheng from the Almaden Research Center near San Jose.
String theory also proposes that gravity plays a stronger role in higher dimensional space, but it is only in our four dimensional space that gravity appears weak.
Since these dimensions become important only on the Planck scale, it’s at that level that gravity re-asserts itself. And if that’s the case, then mini-black holes become a possibility, say the two researchers.
They looked at what properties black holes might have at such a small scale, and determined they could be quite varied.
Black holes lose energy and shrink in size as they do so, eventually vanishing, or evaporating. But this is a very slow process and only the smallest back holes will have had time to significantly evaporate over the enter 14 billion year history of the universe.
The quantization of space on this level means that mini-black holes could turn up at all kinds of energy levels. They predict the existence of huge numbers of black hole particles at different energy levels. And these black holes might be so common that perhaps “All particles may be varying forms of stabilized black holes.”
“At first glance the scenario … seems bizarre, but it is not,” Coyne and Cheng write. “This is exactly what would be expected if an evaporating black hole leaves a remnant consistent with quantum mechanics… This would put a whole new light on the process of evaporation of large black holes, which might then appear no different in principle from the correlated decays of elementary particles.”
They say their research need more experimentation. This may come from the LHC, which could begin to probe the energies at which these kinds of black holes will be produced.
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NBC news is reporting former astronaut Charles F. Bolden Jr. will meet with President Obama in the Oval Office on Monday morning and likely will be appointed the new NASA administrator. NASA has been without an administrator since January, and needs leadership as it faces big changes in the next few years, including the retirement of the space shuttle and the development of replacement vehicles to send humans to space. Bolden has flown four times to space, with more than 680 hours in Earth orbit. If appointed, he would be the first African-American administrator at NASA.
Bolden is regarded as a quiet man but not shy. He made his first spaceflight 23 years ago, and flew on the mission that deployed the Hubble Space Telescope.
Florida senator Bill Nelson flew in space with Bolden in 1986, just before the Challenger tragedy. “Charlie’s credentials are top-notch,” Nelson said. Former administrator Michael Griffin said Bolden would be “perfect” for the job.
The Wide Field Planetary Camera 2 is removed from Hubble. Credit: NASA TV
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While mission specialists John Grunsfeld and Drew Feustel successfully accomplished all their tasks for the first EVA of the Hubble servicing mission, it didn’t come without a little drama. A stubborn bolt threatened to thwart one of the spacewalk’s main goals, replacing the venerable space telescope’s workhorse optical camera with a new and improved instrument. But after a fair amount of old fashioned elbow grease, the Wide Field Planetary Camera 2 was able to be removed. The camera was originally installed in the first Hubble servicing mission in 1993, and was nicknamed “the camera that saved Hubble” because its special optics were able to overcome the spherical aberration in the telescope’s main mirror.
The astronauts also replaced Hubble’s data handling computer – the system that relays data to Earth which gave out last September, delaying this servicing mission, (scheduled to launch last October) until a replacement would be ready.
Watch HD video taken by the shuttle astronauts of Thursday’s activities.
Astronauts removing WFPC2 from Hubble. Credit: NASA TV
Strapped onto the shuttle’s robotic arm, Feustel struggled with a bolt on the old WFPC2 camera for more than an hour. “It’s been in there for 16 years — and it didn’t want to come out,” Grunsfeld said.
Feustel and Grunsfeld worried the bolt might snap, but Mission Control gave Feustel the go-ahead to disable the torque setting on his pistol grip tool.
“We understand if it breaks, then Wide Field (Planetary Camera 2) stays in,” Grunsfeld verified with Mission Control, before Feustel’s high stakes attempt.
“What John said is correct,” capcom Dan Burbank confirmed. Astronaut Drew Feustel loosens the bolt on WFPC2. Credit: NASA TV
Feustel cranked with all his might, and finally it turned.
“I think I got it — It turned, it definitely turned. And it’s turning easily now. Woo hoo, it’s moving out” Feustel said jubilantly.
Once the bolt was freed, Feustel pulled out the old camera, which is about the size of a piano. Feustel carrying the old WFPC2 down to the shuttle's payload bay. Credit: NASA TV
Installing the new $132 million WFPC3 was among the highest priorities for the mission, and will allow Hubble to capture images in infrared, ultraviolet and visible wavelengths of objects from as early as 500 million years after the birth of the universe.
Grunsfeld and Feustel also attached a docking mechanism on Hubble so a robotic spacecraft can attach itself to the telescope when its mission is over and maneuver it through a commanded descent through Earth’s atmosphere to its final resting place in the Pacific Ocean. They also lubricated some of Hubble’s doors and tried to install door mechanisms, which also gave them some trouble. John Grunsfeld works on Hubble. Credit: NASA TV
After installation of WFPC2 and the new data handling system, the Space Telescope Operations Center tested the connections and communications with the instruments, and was able to report to the crew on orbit that both systems passed initial “aliveness” tests.
The 11-day mission is NASA’s fifth and final repair mission to Hubble, with five consecutive spacewalks scheduled. This is NASA’s last chance to service the telescope the end of the shuttle program in 2010. NASA hopes the improvements will keep Hubble operational until at least 2014.
On Friday, two different spacewalkers will replace Hubble’s old and suspect gyroscopes and a set of aging batteries in order to extend the space telescope’s lifetime through at least 2014. Watch NASA TV online to see the EVA, or follow me on Twitter – I’ll be tweeting the highlights of the spacewalk.
The Herschel and Planck spacecraft successfully launched together Thursday from Europe’s Spaceport in Kourou, French Guiana. The Ariane V rocket performed flawlessly, with the rocket’s trajectory matching exactly the predicted flight path. The two spacecraft separated individually and in different directions from the launch vehicle, about four minutes apart, after spinning to orient themselves correctly for their high elliptical orbits. Just 40 minutes after lift-off, Herschel and Planck sent their first radio signals to Earth, confirming that they both are operating in good shape. In a few months, they will arrive at the L-2 (Lagrange) point in space, 1.5 million kilometers (930,000 miles) from Earth, beyond the Moon’s orbit. By early next year, they’ll begin operations to open new windows on the Universe. Herschel will be studying star formation while Planck will be looking back at the Big Bang.
Herschel will be looking at specific points in space while Planck will look at the whole sky. Herschel in 3-D. Credit: Nathanial Burton-Bradford.
This 3-D image of Herschel was created by Nathanial Burton-Bradford. Check out other images at his Flickr page.
Named after the 18th century astronomer who discovered infrared light, the Herschel spacecraft is 7 meters in length and 4 meters wide. The telescope mirror is 3.5 meters wide, 4 times bigger than previous space telescope, and will collect long-wavelength radiation from some of the coldest and most distant objects in the Universe. The mirror is also a technological wonder: it uses 12 silicon carbide petals fused together into a single piece. Herschel will be the only space observatory to cover a spectral range from the far infrared to sub-millimeter.
To detect cold, dark objects, Herschel has to be even colder. 2,400 liters of liquid helium cools the spacecraft to -273 Celsius. Like a thermal camera can see a person’s body heat, Herschel will look beyond dust and gas to see inside star forming regions, study comets and look into the distant universe where galaxies collide and give birth to stars. Scientists are planning for at least three years of operation from Herschel. Planck. Credit: ESA
Planck will be sweeping the whole sky continuously to map out a picture of the Universe as it was 13.7 billion years ago. The spacecraft is four by four meters, with a 1.5 meter primary mirror that is surrounded with a baffle to limit any stray light from nearby objects, the Sun, Earth and Moon. Planck’s detectors have to be cold as well, and will be chilled to between 273 C to just 1/10th of degree above Absolute Zero.
Routine observations with Planck are expected to last for at least 15 months. The mission could be extended depending on the status of helium 3 isotope that is being used to chill the spacecraft.
Planck will test key questions in cosmology, investigating the cosmic microwave background, to ascertain the primordial constituents of the universe, and look for existence of gravitational waves. Planck will journey back in time, while giving us a better understanding of the future.
Ariane V with the Herschel and Planck spacecraft ready to launch. Credit: ESA-CNES-Arianespace / Optique Vidéo du CSG
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The launch of the Herschel and Planck spacecraft is scheduled for 13:12 GMT (9:12 EDT) this morning (Thursday). You can watch it live, starting at 12:40 GMT (8:40 EDT) at this link.
The two spacecraft are launching together in what was originally a cost saving move, but the complexity of preparing two spacecraft at once has caused frequent delays and cost overruns. However, now that launch day is here, hopefully the cutting-edge technologies included in both spacecraft will soon pay off in new discoveries astronomy and cosmology. Read more about the two spacecraft here.
Also, Robert Simpson at Orbiting Frog has some interactive features that show the altitude, velocity and acceleration of the Ariane rocket as it progress through the air into space. You can even click and drag to zoom in on a section of these charts, and move your mouse around inside them to get more information.
And the first of five spacewalks for the Hubble Space Telescope servicing mission starts at around 9:00 am EDT, and will be pretty much an all-day event. Watch live on NASA TV.
Mission patch for STS-125 mission to the Hubble Space Telescope. Credit: NASA
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NASA tracked a piece of orbital debris that came fairly close to space shuttle Atlantis and the Hubble Space Telescope Wednesday evening, but decided no evasive maneuver was required. A 4 inch (10 cm) chunk of a Chinese satellite that was destroyed in a 2007 anti-satellite test came within 1.7 miles (2.8 km) ahead and 150 meters below Atlantis at its closest approach. These potential orbital impacts seem to be occurring routinely for the ISS, and previous shuttle missions have been forced to maneuver out of the way to avoid collisions. The satellite collision in February destroyed a functional satellite, and seemingly, it will be only a matter of time until a serious impact could endanger human lives in orbit. Last week, experts gathered at the International Interdisciplinary Congress on Space Debris, at McGill University in Montreal, Canada and concluded that action must be taken now to reduce the threat to both human spaceflight and satellites from destructive space debris.
“Space debris is primarily a global issue. Global problems need globally solutions, which must be effectively implemented internationally as well as nationally,” said McGill University’s Ram Jakhu, Chair of the Congress. Space debris in Low Earth orbit. Credit: ESA
Over the past decade and a half, the world’s major space agencies have been developing a set of orbital debris mitigation guidelines aimed at stemming the creation of new space debris and lessening the impact of existing debris on satellites and human spaceflight. Most agencies are in the process of implementing or have already implemented these voluntary measures which include on-board passive measures to eliminate latent sources of energy related to batteries, fuel tanks, propulsion systems and pyrotechnics.
But the growing number of developing countries that are launching using satellites, and they need to be encouraged to use these measures as well.
Last week’s Congress suggested that the mitigation guidelines should become mandatory instead of just voluntary, and another possibility mentioned was the establishment of an international regime for dealing with orbital debris similar to the Missile Technology Control Regime, or perhaps the Limited Test Ban Treaty of 1963. There are a variety of other means within international law as well, including codes, declarations and treaties.
Up until now, the debris mitigation process has been focused mainly on the technical aspects, with an enormous amount of research producing excellent recommendations, noted Brian Weeden, Technical Consultant for the Secure World Foundation.
“However, the community is now starting to focus on the legal aspect, which is critical for broadening and strengthening the adoption of debris mitigation guidelines and space safety in general,” Weeden said.
Weeden explained that the recent Congress explored lessons from terrestrial environmental pollution law as well as maritime law that could be applicable to outer space. Furthermore, international law isn’t necessarily the only method for implementing the guidelines. “We are also looking at a variety of other mechanisms, to include economics and industrial standards,” he said.
Additionally, researchers are moving towards the next phase of scientific study. “There is an emerging consensus among the technical community that simply preventing creation of new debris is not going to be enough,” Weeden emphasized.
“At some point we will need to actively remove debris from orbit. Fortunately, new studies are showing that removing as few as five or six objects per year could stabilize the debris population over the long term. The big question right now is which objects to remove first and what is the best method to do so.”
Some of the options for removing space debris include a “space broom” concept that NASA proposed in 1996 called Project Orion, frying space trash with ground-based lasers, an inflatable set of space tongs that could grab and tow objects, or a space vacuum similar to the Planet Eater, which devoured spaceships in an episode of “Star Trek.”
Any of these concepts would require substantial leaps in technology before they are feasible.
It’s Wednesday, so that means its time for another “Where In The Universe” challenge to test your visual knowledge of the cosmos. See if you can name where in the Universe this image is from, and give yourself extra points if you can name the spacecraft responsible for the image. Make your guess and post a comment, but please no links to the answer. Check back sometime on Thursday to find the answer and see how you did.
UPDATE: The answer has now been posted below.
I chose a Hubble image this week, in honor of the current Hubble Servicing Mission. This is, as many of you said, the Cartwheel Galaxy.
The Cartwheel is a ring galaxy, lying about 500 million light-years away in the constellation Sculptor. It has been tidally distorted by an encounter with another galaxy into a ring-and-hub structure.
The striking cartwheel appearance is the result of a smaller intruder galaxy having careened through the core of the larger system, which was probably once a normal spiral similar to the Milky Way. Like a pebble tossed in a lake, the collision sent a ripple of energy into space, plowing gas and dust in front of it.
Expanding at a rate of more than 300,000 km/h, this cosmic tsunami left a burst of new star creation in its wake. Images taken by the Hubble Space Telescope, including the one shown here, have resolved bright blue knots that are gigantic clusters of newborn stars and immense loops and bubbles blown into space by supernovae.
Sounds incredibly violent, but it sure makes a pretty picture!
Radio Telescopes. Credit: University of Washington
Looking for signals from distant civilizations might be an effort in futility, according to scientists who met at Harvard University recently. The dominant view of astronomers at a symposium on the future of human life in the Universe seems to be that if other life is out there, it likely is dominated by microbes or other nonspeaking creatures.
Speakers reviewed how life on Earth arose and the many, sometimes improbable steps it took to create intelligence here. Radio astronomer Gerrit Verschuur said he believes that though there is very likely life out there — perhaps a lot of it — it is very unlikely to be both intelligent and able to communicate with us.
Verschuur presented his take on the Drake equation, formulated by astronomer Frank Drake in 1960, that provides a means for calculating the number of intelligent civilizations that it is possible for humans to make contact with.
The equation relates those chances to the rate of star and habitable planet formation. It includes the rate at which life arises on such planets and develops intelligence, technology, and interplanetary communication skills. Finally, it factors in the lifetime of such a civilization.
Using Drake’s equation, Verschuur calculated there may be just one other technological civilization capable of communicating with humans in the whole group of galaxies that include our Milky Way — a vanishingly small number that may explain why 30 years of scanning the skies for signs of intelligent life has come up empty.
“I’m not very optimistic,” Verschuur said.
Dimitar Sasselov, professor of astrophysics at Harvard and director of the Harvard Origins of Life Initiative, agreed with Verschuur that life is probably common in the universe. He said that he believes life is a natural “planetary phenomenon” that occurs easily on planets with the right conditions.
As for intelligent life, give it time, he said. Though it may be hard to think of it this way, at roughly 14 billion years old, the universe is quite young, he said. The heavy elements that make up planets like Earth were not available in the early universe; instead, they are formed by the stars. Enough of these materials were available to begin forming rocky planets like Earth just 7 billion or 8 billion years ago. When one considers that it took nearly 4 billion years for intelligent life to evolve on Earth, it would perhaps not be surprising if intelligence is still rare.
“It takes a long time to do this,” Sasselov said. “It may be that we are the first generation in this galaxy.”
Several speakers at the event hailed the March launch of NASA’s Kepler space telescope, which is dedicated to the search for Earth-like planets orbiting other stars. Several Harvard-Smithsonian Center for Astrophysics faculty members, including Sasselov, are investigators on the telescope mission. Andrew Knoll describes the beginnings of life on Earth. Photograph by Stephanie Mitchell/Harvard News Office
Sasselov said he expects Kepler to quickly add to the 350 planets already found orbiting other stars. By the end of the summer, he said, it may have found more than a dozen “super Earths” or planets from Earth-size to just over twice Earth’s size that Sasselov expects would have the stability and conditions that would allow life to develop.
If life did develop elsewhere, Andrew Knoll, the Fisher Professor of Natural History, used the lessons of planet Earth to give an idea of what it might take to develop intelligence. Of the three major groupings of life: bacteria, archaea, and eukaryotes, only the eukaryotes developed complex life. And even among the myriad kinds of eukaryotes, complex life arose in just a few places: animals, plants, fungi, and red and brown algae. Knoll said he believes that the rise of mobility, oxygen levels, and predation, together with its need for sophisticated sensory systems, coordinated activity, and a brain, provided the first steps toward intelligence.
It has only been during the past century — a tiny fraction of Earth’s history — that humans have had the technological capacity to communicate off Earth, Knoll said. And, though Kepler may advance the search for Earth-like planets, it won’t tell us whether there’s life there, or whether there has been life there in the past.
Other speakers included J. Craig Venter, Freeman Dyson, Peter Ward, Andy Knoll, Maria Zuber, David Charbonneau, Juan Enriquez, and David Aguilar.
Charlie Brink, manager of the Air Force's X-51 "Waverider" scramjet research project stands with a scale model of the hypersonic aircraft. Credit: Ty Greenlees Dayton Daily News
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The US Air Force has been developing an aircraft that employs an air-breathing scramjet engine, and hopes to run test flights in the fall of 2009. Officials hope the X-51 “Waverider” aircraft will provide high speed aircraft for reconnaissance or strike missions, and eventually the engines will be used for rockets to deploy satellites in space.
“The long-range goal of this for the Air Force is access to space,” said Charlie Brink, an Air Force Research Laboratory propulsion directorate official who manages the X-51 program from Wright-Patterson Air Force Base.
The first test flight of the X-51 will be on Oct. 27, 2009, launched from a B-52 aircraft with a missile booster to at least Mach 4.5, the minimum speed at which the air-breathing scramjet engine operates, before the scramjet kicks in and accelerates the vehicle to at least Mach 6 — six times the speed of sound. The Air Force Research Laboratory expects that the aircraft will fly for about five minutes before crashing into the Pacific. The October flight — and three separate test flights planned in early 2010 — are designed to demonstrate the practicality of using the air-breathing scramjet engine to power and control an aircraft at hypersonic speeds (Mach 5 or greater). The $246.5 million development program has been under development since December 2003.
Scramjet is an acronym for Supersonic Combustion Ramjet. A ramjet has no moving parts and achieves compression of intake air by the forward speed of the vehicle. The scramjet differs from the ramjet in that combustion takes place at supersonic air velocities through the engine. It stays aloft, in part, with lift generated by the shock waves of its own flight. It is mechanically simple, but vastly more complex aerodynamically than a jet engine. Hydrogen is normally the fuel used.
In 2004, NASA conducted flight tests of a hydrogen-based scramjet engine which reached speeds of Mach 9.6, or nearly 7,000 mph, powering an aircraft known as the X-43. However, none of the vehicles survived a flight test.
Brink compares the work of developing the scramjet — to complement aircraft turbine engines and rockets — with aviation’s earlier transition from propellers to jet engines. Air Force leadership will decide the scramjet program’s next step, depending on how the project turns out, Brink said.
Lead Photo Caption: Charlie Brink, manager of the Air Force’s X-51 “Waverider” scramjet research project stands with a scale model of the hypersonic aircraft. Credit: Ty Greenlees Dayton Daily News
