Fraser Cain, Author at Universe Today

September 26, 2007January 24, 2021 by Fraser Cain

Black Hole Mission Returns from the Dead

You can’t keep a good mission down. I guess you can. Actually, it seems like most good missions are kept down (Terrestrial Planet Finder, anyone?). But once, it looks like the good guys are going to win. A cool mission to search for black holes has been resurrected, and will fly in space after all. Wise move NASA, send a spacecraft to help solve one of the most puzzling mysteries in modern astronomy.

The mission is called the Nuclear Spectroscopic Telescope Array, or NuSTAR. NASA was originally planning this mission, capable of detecting nearby black holes with unprecedented sensitivity, but they decided to shelve it because of funding pressures back in 2006.

NuSTAR is part of NASA’s Explorers Program. These are low-cost, regular missions to help solve a specific challenge in astronomy. Previous missions include Swift (for tracking down gamma ray bursts), and GALEX (which performs ultraviolet astronomy). Another mission, WMAP, told us that the Universe is 13.7 billion years old.

If all goes well, NuSTAR will be launched in 2011, bridging the gap between the 2009 launch of the Wide-field Infrared Survey Explorer, and the 2013 launch of the James Webb Space Telescope.

Once in space, it’ll perform deep observations in hard X-rays, searching for the telltale signature of black holes of various sizes and other exotic and extreme objects.

Bad Astronomer Phil Plait was actually involved with the program and gives a personal history about it here.

Original Source: NASA News Release

September 26, 2007December 26, 2015 by Fraser Cain

These are Tough Microbes, But They Don’t Come from Mars

You know the cliche, wherever we find water here on Earth, we find life. But what if the environment is really hostile? So hostile that any living creature would almost never see water. And even when there was water, they were constantly being blasted with radiation. Amazingly, there’s a microbe out there, Deinococcus geothermalis, that can handle some of the harshest environments on the planet – favoured habitats include nuclear power plants. Scientists once suspected that microbes like this might have evolved on Mars. Nope, they’re homegrown.

Of all the different strains of bacteria on Earth, those in the genus Deinococcus are a hardy bunch. They’re extremely resistant to ionizing radiation, they laugh at ultraviolet light, extreme, heat, cold and they don’t mind being completely dried out for long periods. Bathed in acid? Boring.

D. geothermalis is actually a cousin of another microbe called Deinococcus radiodurans. D. radiodurans is capable of withstanding 500 times the radiation that will kill a human – with no loss of viability. The Guiness Book of World records calls D. radiodurans the toughest bacteria in the world, and some scientists have proposed that it actually evolved on Mars and somehow journeyed to Earth.

Researchers have recently sequenced the bacteria’s cousin, D. geothermalis’ entire genome sequence, providing some valuable clues into how a microbe can be so tough, and how they two are related (no Martian explanation necessary).

Their paper describing the results of their sequencing efforts, entitled Deinococcus geothermalis: The Pool of Extreme Radiation Resistance Genes Shrinks will be published in the September 26th issue of the journal Public Library of Science.

The microbe was first discovered in a hot pool at the Termi di Agnano, in Naples, Italy. Other scientists have turned it up in other nasty locations, such as industrial paper machine water, deep ocean subsurface environments, and subterranean hot springs in Iceland.

While working with the microbe, the researchers noted, “the extraordinary survival of Deinococcus bacteria following irradiation has also given rise to some rather whimsical descriptions of their derivation, including that they evolved on Mars.”

In fact, the US Department of Energy is considering D. geothermalis as a possible solution to break down radioactive waste. Which would be good, since it’s often a pest; adhering to the surface of steel, and causing problems in nuclear power plants.

Currently, scientists have no idea why bacteria like D. geothermalis are so hardy to radiation. They’re just as susceptible to normal bacteria to have their DNA broken up by radiation, but they use some kind of efficient repair mechanism to fix the damage quickly.

The big surprise with this research is that it overturns previously held theories about how D. radiodurans protects itself. The two strains of bacteria are both extremely resistant to radiation, and yet D. geothermalis lacks the genes that scientists thought D. radiodurans was using. By comparing genome sequences between the two strains, the researchers were able to narrow down the genes which are likely contributing to the microbes’ tolerance.

This research also overturns the intriguing possibility that D. radiodurans comes from Mars; evolving on the Cosmic Ray blasted surface of the Red Planet. These two strains have enough in common, with traceable evolutionary steps, that the researchers can see how they evolved right here on Earth.

Here’s Dr. Michael J. Daly, an associate professor at the Uniformed Services University of the Health Sciences in Bethesda, “the thermophile Deinococcus geothermalis is an excellent organism in which to consider the potential for survival and biological evolution beyond its planet of origin, as well as the ability of life to survive extremely long periods of metabolic dormancy in high-radiation environments. The current work reinforces the notion that resistance to radiation and desiccation readily evolved on Earth, and that the underlying resistance systems are based on a universal set of repair genes. The work underscores the vulnerability of potential life-inhabiting environments on Mars to contamination by human exploration; and how the efficiency of ordinary DNA repair proteins could be increased, which might be important to astronauts. The growing awareness that there is hardly a habitat on Earth not harboring life is now changing our consensus of consequences for possible life on Mars.”

Sorry Mars, go evolve your own microbes.

Original Source: PLOS Journal article

September 26, 2007December 26, 2015 by Fraser Cain

SOHO Catches a Rare Species of Comet

The most successful comet hunter is not some dedicated amateur who sacrifices night after night searching for icy bodies from the outer Solar System. It’s not a robotic telescope surveying the heavens. Nope, it’s SOHO – a space telescope staring at the Sun; and it discovers comets as a happy side benefit. But recently it turned up something new, one of Halley’s cousins; a periodic comet.

The object is called P/2007 R5, and it wasn’t the first time SOHO had captured images of it. The satellite had actually seen this rare variety of comet on two separate occasions in the past. Instead of falling into the Sun and being destroyed, or getting flung out into a wild orbit, P/2007 R5 takes a very regular elliptical orbit around the Sun.

So if P/2007 R5 had been seen three times by SOHO, why hadn’t anyone noticed before? SOHO sees a lot of comets on a lot of orbits. German PhD student Sebastian Hoenig did notice. He realized that an object that passed by in 1999 had a very similar orbit to another object that came by in 2003. Hoenig calculated the orbit, and predicted that it would be back on September 11, 2007. His prediction was surprisingly accurate; the comet passed through the field of view again, right on schedule.

With that mystery solved, there’s still something puzzling astronomers. P/2007 R5 doesn’t look like a regular comet. It doesn’t have a tail or coma, and some astronomers initially wondered if they were looking at an asteroid, and not a comet. However, on its most recent pass, astronomers were able to study P/2007 R5 a little better, and saw that it does exhibit some cometary behaviour. When it passed within 7.9 million km of the Sun, it flared slightly, just like a comet should.

It’s possible that P/2007 R5 is actually an extinct comet; an object that lost all its volatile gas and ices to the Sun long ago. Objects like this have been long theorized, but never observed.

Original Source: ESA News Release

September 26, 2007December 26, 2015 by Fraser Cain

Tether to Keep Asteroid Explorers Grounded

Here on Earth, gravity keeps us firmly on solid ground. But when astronauts set foot on some of the more exotic objects in the Solar System, just walking is going to be a struggle. In the microgravity of an asteroid, every step astronauts take will send him flying up in a long arc, and maybe out into space. It would be almost impossible to get around. Fortunately, MIT researchers have developed a tether system that could keep astronauts firmly anchored to the surface, but still let them walk around.

When humans first set foot on the Moon, they learned right away that the lower gravity was going to cause problems getting around. It took a few missions, but astronauts finally perfected a silly-looking hop that allowed them to skip around in the 1/6th gravity. But on an asteroid which can be only a few kilometres across, the wrong step could put an astronaut into orbit; the gravity’s that low. As long as the asteroid is above 8 km or so, a wrong footed astronaut would eventually return to the surface, but it would make exploration infuriating.

What the MIT researchers have developed is a tether system that astronauts would attach to the surface of the asteroid. The ropes would be strung completely around the asteroid, sort of like putting a rubber band around a ball. Once the lightweight ropes were in place, they would apply pressure downward on the astronauts, giving them a sort of artificial gravity. The idea will be published in an upcoming issue of the journal Acta Astronautica.

Previous researchers have suggested that astronauts could bolt themselves to the surface of the asteroid, but that might not be possible. Researcher Ian Garrick-Bethell describes the flaw in that plan, “it would be like trying to bolt yourself to a pile of gravel or sand.”

The team envisions a rocket that would fly around the asteroid, unraveling a spool of rope. Once the spacecraft completes an orbit of the asteroid, the loop is formed and then tightened.

Nobody still really knows what the surface of an asteroid will be like. Even this might now work, as the rope might cut into the surface of the asteroid and not be usable to hold an astronaut down. But at least they could use it as a handhold to drag themselves along without flying away.

Original Source: MIT News Release

September 26, 2007December 26, 2015 by Fraser Cain

Astrosphere for September 26th, 2007

Here’s your nice space photo for the day. You might not be aware, but when Venus is at its closest and brightest, it actually looks like a crescent. Here’s a photo captured two days ago by John Chumack.

Got some money to burn? Astronomy.com is reporting that a large metal meteorite is up for sale.

Cosmic Variance has some good advice to would-be graduate students. Here’s how to survive and thrive that grueling educational period.

Popular Mechanics is reporting on a new proposal from Boeing to put a gas station in space. It could make getting to the Moon much easier.

I love this blog. Aerospace worker Damaris B. Sarria really really wants to be an astronaut. Her blog chronicles her journey. And look at this, NASA just opened up applications for more astronauts.

You remember Wolf 359. Come on Star Trek geeks. It’s actually a really close star that you can find in the night sky. Astroprof shows you how.

September 25, 2007December 26, 2015 by Fraser Cain

Dangerous Microbes Toughen Up in Space

Well this news can’t be good. While human bodies tend to get weaker during long duration spaceflight, dangerous microbes just get feistier, returning to Earth even more infectious. A colony of Salmonella typhimurium, the main culprit in food poisoning, flew aboard the space shuttle Atlantis last year. They came back three times more likely to cause disease when compared to control bacteria on the ground.

The discovery was made by researchers from Arizona State University’s Biodesign Institute. Back in September 2006, they included a special experiment flown during the space shuttle Atlantis’ mission STS-115. Don’t worry, the bacteria were placed in three layers of containment to keep the crew safe. At the same time, a control experiment was maintained here on Earth.

The microbes were activated when they were pushed into a special growth chamber containing the nutrients they needed to multiply. They grew for 24 hours, and then astronaut Heidemarie M. Stefanyshyn-Piper pushed a plunger on the experiment that halted their growth, and preserved them. Another group of bacteria got fresh nutrients, so they could continue to grow and multiply.

Once the bacteria were returned to Earth, researchers measured the bacteria’s gene and protein expression, and calculated their virulence. They found that the space traveling bacteria had changed expression of 167 genes. And they found that the bacteria was 3 times as likely to cause disease in animals (we probably don’t want to know how they tested this) as the bacteria grown on the ground.

Why is this happening? The scientists aren’t sure. They have ruled out the near zero-gravity, though. Their best explanation is a poorly understood phenomenon called fluid shear. This is the force of liquid passing over the cells. In microgravity, this fluid shear is very low, similar to the environment of the gastrointestinal track.

As frightening as this sounds, there should be a silver lining here. Salmonella is a particularly nasty strain of bacteria. Learning how it responded to spaceflight should give researchers valuable clues to how it grows and generates its dangerous toxin.

Original Source: ASU News Release

September 25, 2007December 26, 2015 by Fraser Cain

Searching for Objects Even Stranger Than Black Holes

Black holes are already plenty bizarre. Imagine all the mass of several suns compressed down into an object of potentially infinitely small size. But what if you could find an object that’s even stranger: a theoretical “naked singularity”; a black hole spinning so quickly that it lacks an event horizon. A point in space where the density is infinite, yet still visible from the outside.

Here’s the current thinking on black holes. They’re formed when a large star collapses in on itself, lacking the outward pressure to counteract the inward pull of gravity. Once the object reaches a certain size its pull becomes so great that nothing, not even light can escape. The black hole surrounds itself in a shroud of darkness called the event horizon. Any object or radiation that passes through this event horizon is inevitably sucked down into the black hole. And that’s why they’re thought to be black.

But what if that’s not always correct? What if there are circumstances where black holes might not be black at all? It would take some serious spinning, however.

All the black holes discovered so far are thought to be spinning, sometimes more than 1,000 times a second. But in theory, if you could get a black hole spinning ludicrously fast, so that the angular momentum of its spin overcomes the gravitational pull of its mass, it should be able to shed its event horizon. A black hole with 10 times the mass of our Sun would need to be spinning a few thousand times a second.

And here’s the cool part. According to researchers from Duke University and Cambridge, an object spinning like this should be detectable by its gravitational lensing. This is where a massive object, like a black hole, acts like a natural lens to focus the light from a more distant object. If the researchers are right, astronomers should be able to see a telltale signature on the lensed light using existing instruments (or those coming soon).

Their research was published in the September 24th issue of the research journal Physical Review D.

Original Source: Duke University News Release

September 25, 2007December 26, 2015 by Fraser Cain

NASA Dreams Up Exotic Earth-Sized Planets

Science fiction writers have been imagining other worlds for years, and now they’re going to get a little scientific help, thanks to NASA. The agency recently modeled a range of roughly Earth-sized planets, from the familiar to the exotic. Instead of thinking just about planets with Earthlike characteristics, they imagined every possible kind of planet that might exist around other worlds. This should keep the writers busy.

We’re not talking about familiar looking planets, with strange surface features and aliens with pointed ears here, we’re talking about the very extremes of planetary formation: pure water ice, carbon, iron, silicate, carbon monoxide, and silicon carbide, and others which could be mixtures of these various compounds.

The team eventually came up with 14 different types of solid planets that might exist. “We have learned that extrasolar giant planets often differ tremendously from the worlds in our solar system, so we let our imaginations run wild and tried to cover all the bases with our models of smaller planets,” said NASA’s Marc Kuchner. “We can make educated guesses about where these different kinds of planets might be found. For example, carbon planets and carbon-monoxide planets might favor evolved stars such as white dwarfs and pulsars, or they might form in carbon-rich disks like the one around the star Beta Pictoris. But ultimately, we need observations to give us the answers.”

They calculated how gravity should compress planets of varying composition. For example, a pure water planet would be about the same size as the Earth, while an iron planet would be a third our size.

The researchers are hoping their calculations will help future planet hunters identify new discoveries. When powerful planet finders, such as ESA’s Corot mission start making discoveries, astronomers will be working hard to categorize what they’re looking at, based only on the mass and size. Even more powerful observatories, such as the James Webb Space Telescope will let astronomers actually measure the chemical constituents of a planet, and help reveal if we’re looking at a sphere of carbon or water ice.

Their paper will appear in the October 20th issue of the Astrophysical journal.

Original Source: NASA News Release

September 25, 2007December 26, 2015 by Fraser Cain

Astrosphere for September 25th, 2007

First the photo. Winensky captured this great image of the Moon, using a 7-megapixel camera connected to a 3″ reflector telescope. Click this link to see the whole collection, including a mosaic with several images stitched together.

Did any Canadians catch last night’s “Race to Mars”. What did you think of it? Mark Mortimer was good enough to write a review here on Universe Today. Personally, I was so grateful for the careful and accurate presentation of science that I wasn’t too concerned about it being a little boring.

I also caught last night’s premiere of Heroes. Now that was boring, and didn’t have the science to back it up. Pamela Gay gets frustrated by television physics as well – she thinks our heroes should be getting a little hungrier.

What do you use for your skywatching software? Astroprof reviews Stellarium. You can’t go wrong with free.

You’ve got to love the Space Review. Consistently great articles and opinion pieces about space exploration. Check out this one entitled, The rise and fall of great space powers. And here, editor Jeff Faust contemplates Mike Griffin’s recent remarks.

Over at Centauri Dreams, Larry Klaes looks at the rise of submillimetre astronomy.

September 21, 2007December 26, 2015 by Fraser Cain

More Martian Cave Entrances Discovered

More Mars news… NASA’s Mars Odyssey spacecraft has turned up what look like the entrances to caves along the slope of a Martian volcano. If these turn out to be actual tunnels or caves, they could be a scientific goldmine, offering future explorers protection and a unique region to study – perhaps even life could be hiding away from hostile Martian surface environment.

The seven possible cave entrances are dark, and nearly circular, ranging in size from 100 to 250 metres (328 to 820 feet) across. They were discovered by NASA’s Mars Odyssey and Mars Global Surveyor spacecraft. Follow up observations with Odyssey’s infrared cameras confirmed that they could very well be cavernous entrances into underground regions on Mars.

The infrared evidence showed that the temperatures inside the holes changed less than the surrounding regions. “They are cooler than the surrounding surface in the day and warmer at night,” said Glen Cushing of the U.S. Geological Survey’s Astrogeology Team and of Northern Arizona University, Flagstaff, Ariz. “Their thermal behavior is not as steady as large caves on Earth that often maintain a fairly constant temperature, but it is consistent with these being deep holes in the ground.”

One of the downsides of these caves is their altitude. They’re located near the top of a massive Martian volcano called Arsia Mons. At this high altitude, life would have a difficult time coping with the extreme cold and lower air pressure.

Planetary geologists think the caves might have been formed by underground stresses around the volcano. The caves are inline with with other bowl-shaped pits that appear to have been formed when material collapsed. There could be long networks of tunnels and stress fractures. In some cases, the roof just collapsed in completely, and in other places, you might get a cave entrance instead.

The next step is to bring the much more powerful Mars Reconnaissance Orbiter’s camera in to image the regions better. It might be able to shed some light on the mystery.

Original Source: NASA/JPL News Release