Nasa discovers most luminous Galaxy

Nasa discovers most luminous Galaxy

A remote galaxy shining brightly with infrared light equal to more than 300 trillion suns has been discovered using data from NASA’s WISE (Wide-field Infrared Survey Explorer). This galaxy is the most luminous galaxy found to date.

“We are looking at a very intense phase of galaxy evolution” said Chao-Wei Tsai of NASA’s Jet Propulsion Laboratory in Pasadena, California. “This dazzling light may be from the main growth spurt of the galaxy’s black hole.”

The galaxy, known as WISE J224607.57-052635.0, may have a behemoth black hole at its belly, gorging itself on gas.
Supermassive black holes grow by drawing gas and matter into a disk around them. The disk heats up to beyond-sizzling temperatures of millions of degrees, blasting out high-energy, visible, ultraviolet, and X-ray light. The light is blocked by surrounding cocoons of dust. As the dust heats up, it radiates infrared light.

Immense black holes are common at the cores of galaxies, but finding one this big so “far back” in the cosmos is rare. Because light from the galaxy hosting the black hole has traveled 12.5 billion years to reach us, astronomers are seeing the object as it was in the distant past. The black hole was already billions of times the mass of our sun when our universe was only a tenth of its present age of 13.8 billion years.

The new study outlines three reasons why the black holes in the ELIRGs could have grown so massive. First, they may have been born big. In other words, the “seeds,” or embryonic black holes, might be bigger than thought possible.

“How do you get an elephant?” asked Peter Eisenhardt, project scientist for WISE at JPL and a co-author on the paper. “One way is start with a baby elephant.”

The other two explanations involve either breaking or bending the theoretical limit of black hole feeding, called the Eddington limit. When a black hole feeds, gas falls in and heats up, blasting out light. The pressure of the light actually pushes the gas away, creating a limit to how fast the black hole can continuously scarf down matter. If a black hole broke this limit, it could theoretically balloon in size at a breakneck pace. Black holes have previously been observed breaking this limit; however, the black hole in the study would have had to repeatedly break the limit to grow this large.

Alternatively, the black holes might just be bending this limit.

“Another way for a black hole to grow this big is for it to have gone on a sustained binge, consuming food faster than typically thought possible,” said Tsai. “This can happen if the black hole isn’t spinning that fast.”

If a black hole spins slowly enough, it won’t repel its meal as much. In the end, a slow-spinning black hole can gobble up more matter than a fast spinner.

“The massive black holes in ELIRGs could be gorging themselves on more matter for a longer period of time,” said Andrew Blain of University of Leicester in the United Kingdom, a co-author of this report. “It’s like winning a hot-dog-eating contest lasting hundreds of millions of years.”

More research is needed to solve this puzzle of these dazzlingly luminous galaxies. The team has plans to better determine the masses of the central black holes. Knowing these objects’ true hefts will help reveal their history, as well as that of other galaxies, in this very crucial and frenzied chapter of our cosmos.

WISE has been finding more of these oddball galaxies in infrared images of the entire sky captured in 2010. By viewing the whole sky with more sensitivity than ever before, WISE has been able to catch rare cosmic specimens that might have been missed otherwise.

The new study reports a total of 20 new ELIRGs, including the most luminous galaxy found to date. These galaxies were not found earlier because of their distance, and because dust converts their powerful visible light into an incredible outpouring of infrared light.

“We found in a related study with WISE that as many as half of the most luminous galaxies only show up well in infrared light,” said Tsai.

JPL manages and operates WISE for NASA’s Science Mission Directorate in Washington. The spacecraft was put into hibernation mode in 2011, after it scanned the entire sky twice, thereby completing its main objectives. In September 2013, WISE was reactivated, renamed NEOWISE and assigned a new mission to assist NASA’s efforts to identify potentially hazardous near-Earth objects.

For more information on WISE, visit:
http://www.nasa.gov/wise

 

What’s the nearest solar system to ours and does it have an alien life?

What’s the nearest solar system to ours and does it have an alien life?

Since years scientists are searching the space trying to find an Earth-like planet that supports life.
In 2013, a team of European astrophysicists has discovered the most extensive planetary system to date that orbits star KOI-351 which is 2500 light years away from Earth, with seven planets assembled in a similar way as our Solar System, with small rocky planets close to the parent star and gas giant planets at greater distances.
While astronomers have discovered more than 1000 exoplanets, this is the first solar system analogue detected to date.
The planets were discovered by Juan Cabrera, an astrophysicist at the DLR Institute of Planetary Research in Berlin-Adlershof.
“We find planets in any order, at any distance, of any size; even planetary classes that don’t exist in the solar system,” Cabrera said, “No other planetary system shows such a similar architecture to that of our cosmic home as does the planetary system around KOI-351“.

KOI is the abbreviation for “Kepler Object of Interest”, which means the star was observed by NASA’s Kepler space telescope, and classified as a candidate for the existence of exoplanets.

The planets names are: Kepler-90 hKepler-90 gKepler-90 fKepler-90 eKepler-90 dKepler-90 cKepler-90 b. The image hereunder shows the approximate sizes of the planets in this system:

KOI-351 planets sizes

The compact nature of these planets means that most of them orbit on the inside of their star’s habitable zone (the range of orbits where liquid water could be sustained on a planet’s surface). The only one lying inside the habitable zone is the outermost planet Kepler-90 h, which circles its star every 331 days. Being a Jupiter-sized, more likely gaseous world, Kepler-90 h could harbor moons that could have conditions suitable for life. Although out of the reach of current observing techniques, exo-moons around other exoplanets could be discovered by the next generation of space-based planet-hunting telescopes being proposed or constructed at the moment.

A twin to Earth planet with the same temperature and size as Earth has not yet been identified, but the analysis is far from over as scientists continue to search the Kepler data for the tiny signature of such a planet. Other Kepler discoveries include hundreds of star systems hosting multiple planets, and have established a new class of planetary system where planets orbit more than one sun.

 

 

 

Telescopes crash course

Telescopes crash course

I saw this crash course by Astronomer Phil Plait on YouTube about Telescopes and how they work, so I liked sharing it with you:

 

What is Dark Energy, Dark Matter?

What is Dark Energy, Dark Matter?

In early 1990s, the scientists were pretty sure that the Universe is expanding. It might keep expanding and never stops, or it might have enough energy density to stop its expansion and re-collapse. But they were sure that gravity  will slow the expansion as time went on.
Then in 1998, the observations of Hubble Space Telescope of a very distant supernova showed that the Universe expansion was actually accelerating and not as everybody thought, and no one knew how to explain it, but there was something causing it.
So theorists came up with some explanations, they even doubted with Einstein’s theory of gravity that might be something missing, maybe a new theory not yet discovered, so they called the cause of this phenomena “Dark Matter”.

There are lots of information that scientists don’t know about Dark Energy, but they know how much Dark Energy there is because they know how it affects the Universe’s expansion.

Albert Einstein

Albert Einstein

Albert Einstein was the first person to realize that empty space is not nothing. At that time, before Edwin Hubble’s discovery, no one including Einstein knew that the Universe is expanding, and he found that his equation of general relativity did not work for a static universe. Einstein decided to add a factor, that acts like “anti-gravity” and prevents the universe from collapsing. He called this idea, which was represented as an additional term in the mathematical equation representing his theory of gravity, the cosmological constant. Which means that the space can have it’s own energy, because energy is a property of space, and this energy will cause the Universe to expand faster.

Once Einstein knew the universe was expanding, he discarded the cosmological constant. He later called it the “biggest blunder of his life,” according to his fellow physicist George Gamow.
Today astronomers refer to one theory of dark energy as Einstein’s cosmological constant. The theory says that dark energy has been steady and constant throughout time and will remain that way.

A second theory, called quintessence, says that dark energy is a new force and will eventually fade away just as it arose. If the cosmological constant is correct, Einstein will once again have been proven right about something even he thought was a mistake.

In conclusion, there are lots to explore about Dark Matter, and scientists are eager to find out more because it will reveal and solve so many puzzles and questions. Let us see what Professor Michio Kaku has to say about this issue:

 

Incredible Technology: Spiderlike Robots Could Build Giant Space Structures

Incredible Technology: Spiderlike Robots Could Build Giant Space Structures

Humanity could soon be building huge structures in space one piece at a time, the way spiders spin their webs here on Earth.

A company called Tethers Unlimited is developing an in-space manufacturing system called “SpiderFab,” which would use arachnidlike robots to put together large objects in orbit or beyond.

SpiderFab could help build big radio antennas, spacecraft booms and solar arrays in the next decade or so, said Rob Hoyt, CEO and chief scientist of Tethers Unlimited. But he has an even grander vision for the technology (and associated projects the company is working on) over the long haul.

“Our really long-term objective for all of this work is to eventually enable the use of in-situ resources to construct the infrastructure in space needed to support humanity’s expansion throughout the solar system,” Hoyt said March 4 during a presentation with NASA’s Future In-Space Operations (FISO) working group.

Artist's illustration of a robot building a space structure as envisioned by Tethers Unlimited's "SpiderFab" concept. Credit: © Tethers Unlimited Inc.

Artist’s illustration of a robot building a space structure as envisioned by Tethers Unlimited’s “SpiderFab” concept.
Credit: © Tethers Unlimited Inc.

Bringing costs down

Hoyt believes that the current model of spacecraft manufacturing — in which everything is built and assembled on the ground, and is then launched in one piece — leaves plenty of room for improvement.

“It’s a very expensive and time-consuming process, and also, the size of systems is somewhat limited by the size of the deployables that are possible to fold up and fit within a launch shroud,” he said.

SpiderFab is an effort to decrease costs and increase efficiencies. The idea calls for launching raw materials, such as carbon fiber, to orbit. There, robots would transform these materials into truss substructures, and then assemble and integrate these pieces into larger systems.

The potential benefits of such an approach are substantial, Hoyt said.

“The primary one will be that we can deploy apertures and baselines that are much larger than we can currently fit into launch shrouds,” he said. “The payoff of that will be higher power, higher resolution, higher sensitivity and higher bandwidth for a wide range of NASA, DoD [Department of Defense] and commercial space missions.”

Furthermore, objects built in space can be sleeker and simpler than ones launched from the ground, since they don’t need to survive the rigors of launch. That should lead to reductions in design complexity and system mass, which could lead to significant cost savings, Hoyt added.

Case studies

SpiderFab has received two rounds of funding from the NASA Innovative Advanced Concepts (NIAC) program, which aims to encourage the development of potentially game-changing space technologies.

According to Hoyt, case-study analyses conducted under the Phase 1 NIAC award indicated that SpiderFab could achieve order-of-magnitude performance improvements in systems in which “bigger is better” — components such as solar arrays and telescope parts.

As an example of SpiderFab’s potential, Hoyt cited the proposed New Worlds Observer (NWO) space telescope, which would use a huge “starshade” to block out most of the light of a target star, thus allowing its orbiting exoplanets to be imaged directly.

The largest conventionally built starshade would be about 203 feet (62 meters) wide, Hoyt said. Employing on-orbit manufacturing with the same amount of mass would increase that diameter to 406 feet (124 m), allowing NWO to peer twice as close to target stars — and thus observe more planets, Hoyt added.

In addition, launching the starshade in raw-material form, rather than in finished form, reduces its volume by a factor of 30, thus allowing a smaller (and therefore cheaper) rocket to be used for the potential mission, Hoyt said.

“All those benefits combine to enable NASA to basically buy 16 times more habitable planets per taxpayer dollar,” he said.

Tethers Unlimited has already built a machine that makes supporting truss structures here on Earth using a process akin to 3D printing. Here's an artist's concept of the "trusselator" technology at work in space. Credit: © Tethers Unlimited Inc.

Tethers Unlimited has already built a machine that makes supporting truss structures here on Earth using a process akin to 3D printing. Here’s an artist’s concept of the “trusselator” technology at work in space.
Credit: © Tethers Unlimited Inc.

How it would work

At the heart of the SpiderFab concept is a multiarmed robot that would fabricate structural elements with one “spinneret” and use another one to join these pieces together as it crawls about on the ever-growing “web.”

Tethers Unlimited, which is based in Bothell, Washington, is working to develop the various technologies required to pull off such an ambitious vision, Hoyt said.

For example, in a project funded by NASA’s Small Business Innovation Research (SBIR) program, the company already built a machine that creates lightweight structural trusses from raw carbon-fiber spools, using a process akin to 3D printing.

This “trusselator,” which is about the size of a microwave oven, can churn out truss — the type of stuff that could be put together to form a spacecraft boom and other systems — at the rate of 2 inches (5 centimeters) per minute, Hoyt said.

“Under the NIAC and SBIR work, I think we’ve already validated the basic feasibility of the key processes required” for the broad SpiderFab concept, he said.

The team is currently working on a second-generation trusselator, and hopes to have a prototype ready by early summer. Tethers Unlimited wants to launch a small “MakerSat” a couple of years from now to demonstrate the process on orbit. This spacecraft may end up being a CubeSat deployed from the International Space Station, Hoyt said.

The company has also bought a commercially available Baxter robot, and is using the machine to learn how to assemble trusses robotically. Hoyt and his colleagues will continue to develop and refine this process on the ground, and then aim to launch a “MakerSat 2” to prove it out in space — perhaps by building the truss structure for a big starshade.

“In a perfect world — if funding flowed and the contracting process didn’t drag on forever — we think we could get to be able to build very large support structures for antennas and solar arrays, and those sorts of components, in the early 2020s,” Hoyt said.

Source: Space.com