ESA's GAIA satellite set to discover thousands of planets in Milky Way

Princeton University and Lund University researchers project that the recently launched ESA's Gaia satellite could discover tens of thousands of planets during its five-year mission. 

In this image, the colored portions indicate the number of observations Gaia would make of a particular part of the sky during its mission; the scale at the bottom indicates the number of observations from zero (purple) to 200 (red). 

The total number of observations of any part of the sky ranges from about 60 at low ecliptic latitudes to about 80 at high ecliptic latitudes, with a maximum of about 150-200 at intermediate latitudes. 

From these many different observations of each star, the highly accurate Gaia measurements will reveal the tiny star motion, or "wobble," that results from any orbiting planet. 

Credit: Lennart Lindegren, Lund University

A recently launched European satellite could reveal tens of thousands of new planets within the next few years, and provide scientists with a far better understanding of the number, variety and distribution of planets in our galaxy, according to research published today.

Researchers from Princeton University and Lund University in Sweden calculated that ESA's observational satellite Gaia could detect as many as 21,000 exoplanets, or planets outside of Earth's solar system, during its five-year mission.

If extended to 10 years, Gaia could detect as many as 70,000 exoplanets, the researchers report.

The researchers' assessment is accepted in the Astrophysical Journal and was published Nov. 6 in advance-of-print on arXiv, a preprint database run by Cornell University.

Exoplanets will be an important "by-product" of Gaia's mission, Perryman said. Built and operated by the European Space Agency (ESA) and launched in December 2013, Gaia will capture the motion, physical characteristics and distance from Earth, and one another, of roughly 1 billion objects, mostly stars, in the Milky Way galaxy with unprecedented precision.

The presence of an exoplanet will be determined by how its star "wobbles" as a result of the planet's orbit around it.

More important than the numbers of predicted discoveries are the kinds of planets that the researchers expect Gaia to detect, many of which, such as planets with multi-year orbits that pass directly, or transit, in front of their star as seen from Earth, are currently difficult to find, explained first author Michael Perryman, an adviser on large scientific programs who made the assessment while serving as Princeton's Bohdan Paczyński Visiting Fellow in the Department of Astrophysical Sciences, Dublin.

The satellite's instruments could reveal objects that are considered rare in the Milky Way, such as an estimated 25 to 50 Jupiter-sized planets that orbit faint, low-mass stars known as red dwarfs.

One of the main objectives of the Gaia mission is to establish the currently uncertain distance from Earth to various stars using high-precision triangulation, which would allow a much better understanding of the properties of the stars and the planets orbiting them. 

Of the 1,163 confirmed transiting planets, which pass directly in front of their stars as seen from Earth, there are 644 distinct host stars; less than 200 have accurately known distances from Earth. 

This image shows the distances from Earth (center) to the stars (black dots) of transiting exoplanets. 

The inner dashed circle has a radius of 100 parsecs (about 326 light years) with the middle and outer circles corresponding to 500 parsecs (1,630 light years) and 1,000 parsecs (3,260 light years), respectively. 

The cluster of points to the lower right represents the transiting planets discovered by NASA's Kepler satellite. For each star, the straight lines extending from the circle indicate the current uncertainty of its distance from Earth. 

Credit: Michael Perryman

Unique planets and systems, such as planets that orbit in the opposite direction of their companions, can inspire years of research, Perryman said.

"It's not just about the numbers. Each of these planets will be conveying some very specific details, and many will be highly interesting in their own way," Perryman said.

"If you look at the planets that have been discovered until now, they occupy very specific regions of discovery space. Gaia will not only discover a whole list of planets, but in an area that has not been thoroughly explored so far."

More information: Michael Perryman, Joel Hartman, Gáspár Bakos and Lennart Lindegren. 2014. "Astrometric exoplanet detection with Gaia." Astrophysical Journal. Arti¬cle first pub-lished to the Cornell University arXiv preprint database: Nov. 6, 2014.

ESA CryoSat-2 and Jason-1 Satellites detect 'thousands' of new ocean-bottom mountains

ESA CryoSat-2 and NASA's Jason-1 satellites capture new gravity data.

ESA's CryoSat-2 and NASA's Jason-1 satellites capture new gravity data gives us our clearest view yet of the shape of the ocean floor

It is not every day you can announce the discovery of thousands of new mountains on Earth, but that is what a US-European research team has done.

What is more, these peaks are all at least 1.5km high.

ESA's CryoSat-2 Earth Observation satellite.

Credit: ESA

The reason they have gone unrecognised until now is because they are at the bottom of the ocean.

Prof Dave Sandwell (UCSD) and colleagues used Cryosat-2 and Jason-1 radar satellites to discern the mountains' presence under water and report their findings in Science Magazine.

"In the previous radar dataset we could see everything taller than 2km, and there were 5,000 seamounts," Prof Sandwell told reporters.

"With our new dataset, and we haven't fully done the work yet, I'm guessing we can see things that are 1.5km tall.

"That might not sound like a huge improvement but the number of seamounts goes up exponentially with decreasing size.

"So, we may be able to detect another 25,000 on top of the 5,000 already known," the Scripps Institution of Oceanography researcher explained.

The new detailed map of the sea floor is available here.

Knowing where the seamounts are is important for fisheries management and conservation, because it is around these topographic highs that wildlife tends to congregate.

The roughness of the seafloor is important also as it steers currents and promotes mixing, behaviours that are critical to understanding how the oceans transport heat and influence the climate.

But our knowledge of the seafloor is poor; witness the problems they have had searching for the missing Malaysia Airlines jet MH370, which is believed to have crashed west of Australia.

Seeing fracture zones tells scientists about the movement of the continents
The problem is that saltwater is opaque to all the standard techniques that are used to map mountains on land.

Ship-borne echosounders can gather very high-resolution information by bouncing sound off bottom structures, but less than 10% of the global oceans have been properly surveyed in this way because of the effort it involves.

Iceland Rocked by Thousands of intense earthquakes

This is a Saturday May 8 2010 file image taken from video of a column of ash rising from Iceland's Eyjafjallajokul volcano. 

It was reported Tueday Aug. 19, 2014 that thousands of small intense earthquakes are rocking Iceland amid concerns that one of the country's volcanoes may be close to erupting. 

Iceland has raised its aviation alert level for the risk of a possible volcanic eruption to orange, the second-most severe level. 

The alert is worrisome because of the chaos that followed the April 2010 eruption of Eyjafjallajokul, when more than 100,000 flights were cancelled because volcanic ash floating in the atmosphere is considered an aviation safety hazard. 

Credit: AP Photo/ APTN

Thousands of small intense earthquakes are rocking Iceland amid concerns that one of the country's volcanoes may be close to erupting.

Iceland has raised its aviation alert level for the risk of a possible volcanic eruption to orange—the second-most severe level.

The alert is worrisome because of the chaos that followed the April 2010 eruption of Eyjafjallajokul, when more than 100,000 flights were cancelled because volcanic ash floating in the atmosphere is considered an aviation safety hazard.

Some 3,000 earthquakes have taken place since Saturday in Bárðarbunga (pronounced [b'aurðarbuŋka]), a subglacial stratovolcano located under Iceland's largest glacier.

Iceland's Meteorological Office said that no earthquakes above magnitude 3 have been recorded in the last 24 hours.

Seismologists said Tuesday magma is moving, but it is traveling horizontally.

NASA WISE survey finds thousands of new stars, but no 'Planet X'

A nearby star stands out in red in this image from the Second Generation Digitized Sky Survey (DSS). 

Image credit: DSS /NASA/JPL-Caltech

After searching hundreds of millions of objects across our sky, NASA's Wide-Field Infrared Survey Explorer (WISE) has turned up no evidence of the hypothesized celestial body in our solar system commonly dubbed "Planet X."

Researchers previously had theorized about the existence of this large, but unseen celestial body, suspected to lie somewhere beyond the orbit of Pluto.

In addition to "Planet X," the body had garnered other nicknames, including "Nemesis" and "Tyche."

This recent study, which involved an examination of WISE data covering the entire sky in infrared light, found no object the size of Saturn or larger exists out to a distance of 10,000 astronomical units (au), and no object larger than Jupiter exists out to 26,000 au.

One astronomical unit equals 93 million miles. Earth is 1 au, and Pluto about 40 au, from the Sun.

Kevin Luhman

"The outer solar system probably does not contain a large gas giant planet, or a small, companion star," said Kevin Luhman of the Center for Exoplanets and Habitable Worlds at Penn State University, author of a paper 'A SEARCH FOR A DISTANT COMPANION TO THE SUN WITH WISE' in the Astrophysical Journal describing the results.

But searches of the WISE catalogue are not coming up empty. A second study reveals several thousand new residents in our Sun's "backyard," consisting of stars and cool bodies called brown dwarfs.

Ned Wright

"Neighbouring star systems that have been hiding in plain sight just jump out in the WISE data," said Ned Wright of the University of California, Los Angeles (UCLA), the principal investigator of the mission.

WISE survey finds thousands of new stars, but no 'Planet X'

Data from NASA's WISE, has found no evidence for a hypothesized body sometimes referred to as "Planet X." 

Credit: Penn State University

The second WISE study, which concentrated on objects beyond our solar system, found 3,525 stars and brown dwarfs within 500 light-years of our Sun.

Davy Kirkpatrick

"We're finding objects that were totally overlooked before," said Davy Kirkpatrick of NASA's Infrared and Processing Analysis Center (IPAC) at the California Institute of Technology, Pasadena, Calif.

Kirkpatrick is lead author of the second paper, also in the Astrophysical Journal.

Some of these 3,525 objects also were found in the Luhman study, which catalogued 762 objects.

The WISE mission operated from 2010 through early 2011, during which time it performed two full scans of the sky, with essentially a six-month gap between scans.

The survey captured images of nearly 750 million asteroids, stars and galaxies. In November 2013, NASA released data from the AllWISE program, which now enables astronomers to compare the two full-sky surveys to look for moving objects.

In general, the more an object in the WISE images appears to move over time, the closer it is. This visual clue is the same effect at work when one observes a plane flying low to the ground versus the same plane flying at higher altitude.

Though traveling at the same speed, the plane at higher altitude will appear to be moving more slowly.

Searches of the WISE data catalogue for these moving objects are uncovering some of the closest stars.

The discoveries include a star located about 20 light-years away in the constellation Norma, and as reported last March, a pair of brown dwarfs only 6.5 light-years away, making it the closest star system to be discovered in nearly a century.

Despite the large number of new solar neighbors found by WISE, "Planet X" did not show up.

Previous speculations about this hypothesized body stemmed in part from geological studies that suggested a regular timing associated with mass extinctions on Earth.

The idea was that a large planet or small star hidden in the farthest reaches of our solar system might periodically sweep through bands of outer comets, sending them flying toward our planet.

The Planet X-based mass extinction theories were largely ruled out even prior to the new WISE study.

WISE survey finds thousands of new stars, but no 'Planet X'

The third closest Binary star system to the sun, called WISE J104915.57-531906, is at the center of the larger image, which was taken by NASA's WISE. 

Credit: NASA /JPL /Gemini Observatory /AURA /NSF

Other theories based on irregular comet orbits had also postulated a Planet X-type body.

The new WISE study now argues against these theories as well.

Both of the WISE searches were able to find objects the other missed, suggesting many other celestial bodies likely await discovery in the WISE data.

"We think there are even more stars out there left to find with WISE. We don't know our own sun's backyard as well as you might think," said Ned Wright.

WISE was put into hibernation upon completing its primary mission in 2011.

In September 2013, it was reactivated, renamed NEOWISE and assigned a new mission to assist NASA's efforts to identify the population of potentially hazardous near-Earth objects.

NEOWISE will also characterise previously known asteroids and comets to better understand their sizes and compositions.