Month: September 2016

A new map of the Milky Way shows that the spiral arm that contains our solar system is much larger than previously believed.

New Scientist reports that a group of scientists from the Purple Mountain Observatory in Nanjing, China discovered evidence that our Milky Way neighborhood is just as bulky as comparable areas elsewhere in the galaxy.

The solar system has been thought to be located in the spiral structure called the Local Arm, or the Orion Spur, which scientists have believed is much smaller than the neighboring Perseus Arm.  Other Milky Way appendages are as bulky as the Perseus Arm, and even those which are sporting fewer stars make up for the lesser star count by containing as much gas as the largest arms.

The solar system’s home arm is now looking like it can keep up in the arm size race thanks to a new comprehensive study of the galaxy’s form.

The research team collected data using the Very Long Baseline Array in New Mexico to map the high-mass clouds in the spiral arms.  The team also calculated the clouds’ distances.

“Radio telescopes can ‘see’ through the galactic plane to massive star forming regions that trace spiral structure, while optical wavelengths will be hidden by dust,” Ye Zu of the Purple Mountain Observatory said.

The mapping project revealed a Milky Way that does not have well-defined arms, but rather a number of spiral structures with branches and small spurs.

The so-called Orion Spur in which Earth resides turns out to not be a spur after all, but more like one of the Milky Way’s huge spiral arms.  A spur was also found to connect the Local Arm with the large Sagittarius Arm.

“This lane has received little attention in the past because it does not correspond with any of the major spiral arm features of the inner galaxy,” the study authors wrote.

Further efforts are underway to better map our galaxy, including a 3D mapping project with the European Space Agency’s Gaia spacecraft.

The study was published in the journal Science Advances.

The largest radio telescope in the world, located in China’s Guizhou Province, is commencing operations.

Sky and Telescope reports that the enormous telescope, called the Five-hundred-meter Aperture Spherical Telescope (FAST), is up and running.  FAST sports a 500-meter-wide radio collection dish, making it the largest filled-in single-dish telescope ever constructed.

FAST’s dish, which is equivalent in size to 30 soccer fields, affords the telescope a collecting area of 70,000 square meters.  The telescope was built in an area surrounded by mountains in order to block as much radio interference as possible.  To further cut down on interference, China relocated over 9,000 people from surrounding villages while constructing the telescope.

Construction began in 2011 and required the placement of 4,450 reflecting panels to complete the giant dish.  The panels are connected to actuators which are used to fine-tune the panels’ positions to maintain the overall dish shape and achieve maximum focus.

FAST is expected to collect a vast amount of data, to the tune of around three petabytes every year.

“This system is already being used by a whole suite of observatories around the world,” Andreas Wicenec of the University of Western Australia said. “During the last few years, the software has been significantly upgraded to support very large data streams like the ones coming out of Square Kilometer Array precursors.”

Once fully tested and proven to be properly functioning, FAST will become available to international science teams looking to collect data on radio signals from distant space.

“As soon as the telescope works normally, the Time Allocation Committee (TAC) will distribute observation time according to the scientific value of the proposals. Proposals from foreign scientists will be accepted as well.  There will also be foreigners on the TAC,” Nan Rendong of FAST said.

A number of humongous glowing space “blobs” have puzzled scientists for years, but now the source of their enigmatic glow may be revealed.

According to NPR, the space blob under recent study was first spotted in the late 1990s and appeared to be a gigantic cloud of glowing hydrogen gas.  Other such blobs were discovered, many around ten times as large as the Milky Way.

Astronomers dubbed the massive, bright objects “Lyman-alpha blobs,” after the wavelengths they emitted and with the use of the word “blob” as a touch of humor — “like the blob from outer space or something like that,” as Chuck Steidel of Caltech explained.

The primary mystery surrounding the huge objects was the fact that they glowed with no obvious light source.

In a new study, researchers took a deeper look into one of the largest blobs using the ALMA telescope in Chile.  There they were able to identify two large galaxies hidden within the enormous gas cloud.  The galaxies had been previously obscured from view due to the large amount of dust surrounding them.

The galaxies are creating new stars at a fast pace, each producing the equivalent of 100 suns every year.  The intense light generated by the galaxies is lighting up the surrounding gas.

The researchers equate the effect with the kind of light scattering that happens around a streetlight in foggy weather.

“You see a sort of halo around the streetlight because the light from the central streetlight is scattering off water droplets in the fog,” Jim Geach of the University of Hertfordshire said.  “It’s kind of analogous to what we’re seeing with these Lyman-alpha blobs.”

The discovery of the source of one blob’s light suggests that other such glowing space blobs are likely lit up by similar means.

“It’s too early to say that this is going to end up being typical, but it’s pretty interesting,” Steidel says. “It’s nice to see that one’s gut feeling turns out to be supported by something other than speculation.”

The study was published in The Astrophysical Journal.