Space ‘Scale’ to Weigh Black Holes

black-hole

A new way of measuring the mass of supermassive black holes could revolutionize our understanding of how they form and help to shape galaxies.

The technique, developed by a team including Oxford University scientists, can spot the telltale tracer of carbon monoxide within the cloud of gas (mostly hydrogen) circling a supermassive black hole at the centre of a distant galaxy. By detecting the velocity of the spinning gas they are able to ‘weigh’ (determine the mass) of the black hole.

An image of NGC 4526 showing molecular gas. Image: NASA/ESA/Tim Davies

An image of NGC 4526 showing molecular gas. Image: NASA/ESA/Tim Davies

Detailed information on supermassive black holes, thought to be at the heart of most galaxies, is scarce: it has taken 15 years to measure the mass of just 60. The problem is that most other supermassive black holes are too far away to examine properly even with the Hubble Space Telescope.

The new method, when combined with new telescopes such as ALMA (Attacama Large Millimetre/submillimetre Array), promises to extend this black hole ‘weigh-in’ to thousands of distant galaxies. It will also enable the study of black holes in spiral galaxies (similar to our own Milky Way), which are hard to target using currently available techniques.

A report of the research is published in this week’s Nature (citation below).

The team demonstrated the new technique on the supermassive black hole at the centre of a galaxy, NGC 4526, in the constellation of Virgo. NGC 4526 was chosen as a test because it has been widely studied but the team believe the technique will work on a wide range of different galaxies.

Tim Davis of the European Southern Observatory, lead author of the paper, said, “We observed carbon monoxide molecules in the galaxy we were monitoring using the Combined Array for Research in Millimetre-wave Astronomy (CARMA) telescope. With its super-sharp images we were able to zoom right into the centre of the galaxy and observe the gas whizzing around the black hole. This gas moves at a speed which is determined by the black-hole’s mass, and the distance from it. By measuring the velocity of the gas at each position, we can measure the mass of the black hole.”

Dr Michele Cappellari of Oxford University’s Department of Physics, an author of the paper, said, “Because of the limitations of existing telescopes and techniques we had run out of galaxies with supermassive black holes to observe. Now with this new technique and telescopes like ALMA we will be able to examine the relationship between thousands of more distant galaxies and their black holes giving us an insight into how galaxies and black holes co-evolve. Importantly our ‘weigh-in’ technique will work for all kinds of galaxies, including spiral galaxies which are particularly difficult to observe with previous techniques.”

Dr Martin Bureau of Oxford University’s Department of Physics, an author of the paper, said: “The ALMA telescope is now in the final stages of construction and our team is currently bidding for time to use it for our black hole survey. If all goes according to plan we could begin our survey by the end of this year.”

Source: University of Oxford

Reference:

Davis, T., Bureau, M., Cappellari, M., Sarzi, M., & Blitz, L. (2013). A black-hole mass measurement from molecular gas kinematics in NGC4526 Nature DOI: 10.1038/nature11819

Ridges on Mars Suggest Ancient Flowing Water

A 3-D image of an impact crater in the Nilosyrtis area on the Martian surface shows long pipe-like ridges, fossilized evidence of ancient subsurface water flow. Credit: NASA Mars Reconnaissance Orbiter

A 3-D image of an impact crater in the Nilosyrtis area on the Martian surface shows long pipe-like ridges, fossilized evidence of ancient subsurface water flow. Credit: NASA Mars Reconnaissance Orbiter

Networks of narrow ridges found in impact craters on Mars appear to be the fossilized remnants of underground cracks through which water once flowed, according to a new analysis by researchers from Brown University.

The study, in press in the journal Geophysical Research Letters (cited below) bolsters the idea that the subsurface environment on Mars once had an active hydrology and could be a good place to search for evidence of past life. The research was conducted by Lee Saper, a recent Brown graduate, with Jack Mustard, professor of geological sciences.

The ridges, many of them hundreds of meters in length and a few meters wide, had been noted in previous research, but how they had formed was not known. Saper and Mustard thought they might once have been faults and fractures that formed underground when impact events rattled the planet’s crust. Water, if present in the subsurface, would have circulated through the cracks, slowly filling them in with mineral deposits, which would have been harder than the surrounding rocks. As those surrounding rocks eroded away over millions of years, the seams of mineral-hardened material would remain in place, forming the ridges seen today.

Mineral deposits mark subsurface water flow A photo taken by the Mars Reconnaissance Orbiter shows ridges formed by fossilized subsurface water flow. Orientation of the ridges, mapped by researchers, is consistent with fractures formed by impact events. Credit: NASA and Mustard Lab/Brown University

Mineral deposits mark subsurface water flow
A photo taken by the Mars Reconnaissance Orbiter shows ridges formed by fossilized subsurface water flow. Orientation of the ridges, mapped by researchers, is consistent with fractures formed by impact events. Credit: NASA and Mustard Lab/Brown University

To test their hypothesis, Saper and Mustard mapped over 4,000 ridges in two crater-pocked regions on Mars, Nili Fossae and Nilosyrtis. Using high-resolution images from NASA’s Mars Reconnaissance Orbiter, the researchers noted the orientations of the ridges and composition of the surrounding rocks.

The orientation data is consistent with the idea that the ridges started out as fractures formed by impact events. A competing hypothesis suggests that these structures may have been sheets of volcanic magma intruding into the surrounding rock, but that doesn’t appear to be the case. At Nili Fossae, the orientations are similar to the alignments of large faults related to a mega-scale impact. At Nilosyrtis, where the impact events were smaller in scale, the ridge orientations are associated with each of the small craters in which they were found. “This suggests that fracture formation resulted from the energy of localized impact events and are not associated with regional-scale volcanism,” Saper said.

Importantly, Saper and Mustard also found that the ridges exist exclusively in areas where the surrounding rock is rich in iron-magnesium clay, a mineral considered to be a telltale sign that water had once been present in the rocks.

“The association with these hydrated materials suggests there was a water source available,” Saper said. “That water would have flowed along the path of least resistance, which in this case would have been these fracture conduits.”

As that water flowed, dissolved minerals would have been slowly deposited in the conduits, in much the same way mineral deposits can build up and eventually clog drain pipes. That mineralized material would have been more resistant to erosion than the surrounding rock. And indeed, Saper and Mustard found that these ridges were only found in areas that were heavily eroded, consistent with the notion that these are ancient structures revealed as the weaker surrounding rocks were slowly peeled away by wind.

Taken together, the results suggest the ancient Martian subsurface had flowing water and may have been a habitable environment.

“This gives us a point of observation to say there was enough fracturing and fluid flow in the crust to sustain at least a regionally viable subsurface hydrology,” Saper said. “The overarching theme of NASA’s planetary exploration has been to follow the water. So if in fact these fractures that turned into these ridges were flowing with hydrothermal fluid, they could have been a viable biosphere.”

Saper hopes that the Curiosity rover, currently making its way across its Gale Crater landing site, might be able to shed more light on these types of structures.

“In the site at Gale Crater, there are thought to be mineralized fractures that the rover will go up and touch,” Saper said. “These are very small and may not be exactly the same kind of feature we studied, but we’ll have the opportunity to crush them up and do chemical analysis on them. That could either bolster our hypothesis or tell us we need to explore other possibilities.”

Source: Elsevier

Reference:

Lee Saper, & John F. Mustard (2013). Extensive linear ridge networks in Nili Fossae and Nilosyrtis, Mars: Implications for fluid flow in the ancient crust Geophysical Research Letters : 10.1002/grl.50106

Beliefs and Questions About the Paranormal

Heaven

While people of different beliefs from all over the world believe in an afterlife, many of them can’t seem to agree with each other or accept views other than their own. Yet, men have talked about the supernatural since the beginning of time. Recently, authors like Bill Guggenheim, Dr. Raymond Moody, and Dr. Eben Alexander have written books that explore the existence of the consciousness after death. Read More →

First Autonomous Telemedicine Robot for Hospitals

Telemedicine Robot

Image Credit: BBC

iRobot Corp. (NASDAQ: IRBT), a leader in delivering robotic solutions, announced that the RP-VITA Remote Presence Robot has received 510(k) clearance by the U.S. Food and Drug Administration (FDA) for use in hospitals. RP-VITA is the first autonomous navigation remote presence robot to receive FDA clearance. Read More →

Sending Odors and Tastes as an Email Attachment

Image Credit: Shutterstock/Andrea Danti

Image Credit: Shutterstock/Andrea Danti

Research into cybernetic organs has been largely focused on replacements for disabled individuals who have lost a limb. Electronic noses and tongues are designed for a radically different purpose. Humans perceive different chemicals as various tastes and odors. Many types of additives are industrially manufactured to replicate certain flavors or scents. Read More →

Meet Baxter – the $22,000 Robot

Baxter

Realistic views of robots are usually centered on grappling arms hidden behind safety cages, but Rethink Robotics is working to change that. The Massachusetts-based company produces the Baxter line of robots shown above. These machines are designed to adapt to their local environment so that even unskilled labor can train them to do work. Perhaps equally important, they’re affordable and designed with simplicity in mind. Read More →

Future Computing: Meet the Flexible Paper Computer

Paper Tablet

A collaborative project between Queen’s University, Plastic Logic, and Intel Labs has yielded one of the more exciting unveilings during CES 2013: a flexible paper computer. Dubbed the “PaperTab” tablet, the device looks and feels like a normal piece of paper, however, it’s fully interactive with a flexible, hi-resolution 10.7” touchscreen plastic display powered by a second generation Intel Core i5 Processor. Read More →

Studying Ancient Earth’s Geochemistry

Image Credit: University of Washington

Image Credit: University of Washington

Researchers still have much to learn about the volcanism that shaped our planet’s early history. New evidence from a team led by Carnegie’s Frances Jenner demonstrates that some of the tectonic processes driving volcanic activity, such as those taking place today, were occurring as early as 3.8 billion years ago. Their work is published in Geology [citation below]. Read More →

Soft Lego Built in the Computer

Simulation snapshot of a cubic crystal built of soft patchy diblock star polymers. (Copyright: American Physical Society)

Simulation snapshot of a cubic crystal built of soft patchy diblock star polymers. (Copyright: American Physical Society)

Barbara Capone of the Computational Physics Group of the University of Vienna has developed a new method for the construction of building blocks at the nanoscale. The researcher in Soft Matter Physics, who works at the group of Christos Likos, Professor for Multiscale Computational Physics, is specialized on topics of self-assembly of materials at the nanoscale and she has published, together with her colleagues, a paper at the prestigious Journal “Physical Review Letters” on “soft Lego” (cited below). Read More →

Clean Energy Action Plan for U.S.

Clean-Green-Energy

The global clean energy marketplace is expanding rapidly, but the competitive position of American industry is at risk because of increased competition abroad and uncertain policies at home, according to a report released today by The Pew Charitable Trusts. Read More →