WR 104 - Potential Space Nasty

I really like "bad astronomy" articles, but even more so when they admit they are scared. In this instance it is a binary star known as Wr 104. At a distance of 5000-8000 light years a supernova is not expected to harm us. But a Gamma Ray Burst might, especially if it is aimed straight at us!

GRBs are a special type of supernova. When a very massive star explodes, the inner core collapses, forming a black hole, while the outer layers explode outwards. Due to a complex and fierce collusion of forces in the core, two beams of raw fury can erupt out of the star, mind-numbing in their power. Composed mostly of high-energy gamma rays, they can carry more energy in them than the Sun will put out in its entire lifetime. They are so energetic we can see them clear across the Universe, and having one too close would be bad.

...Worse, the flood of subatomic particles from such a GRB may in fact be more dangerous. These cosmic rays hit the air and create fast particles called muons, which would rain down over the Earth. How bad is that? Actually, it’s pretty uncertain; the number of variables involved is large, and the modeling of this is notoriously difficult. It’s not even clear that the cosmic rays from a GRB at this distance would even reach us, and if they did, what exactly would happen. The worst-case scenario is pretty bad — large scale mass extinctions...

http://blogs.discovermagazine.com/badastronomy/2008/03/03/wr-104-a-nearby-gamma-ray-burst/

Cosmic Rays Reach Modern Era High

Within the "Space Age" (since the 1950s) this year marks the greatest intensity of cosmic rays reaching planet Earth. Not coincidentally, this year is also the lowest solar minimum of the period. Basically more solar activity means more solar wind which enhances the heliosphere, the Sun's magnetic field that helps protect us.

It's a double-edged sword; at one end of the scale we get more cosmic rays, which means greater levels of mutation (cosmic rays are responsible for roughly 50% of random genetic damage), and at the other end we get an increase in solar flares, which can cause us harm when aimed in our direction.

If we could choose, we'd like the sun to be average, always.

Cosmic Ray Hotspots Located

Researchers working from seven years worth of results from the Los Alamos’ Milagro cosmic-ray observatory have found that the two spots (marked in red above), have been sending us more cosmic rays than would be expected statistically.

Interestingly, these hotspots, located near the constellations of Gemini and Taurus, are very close to Orion - a place well-known to alternative Egyptologists.

The two possibilites presented are:

a) something in that area that we don't presently understand is emitting the cosmic rays

b) something we have not yet discovered is acting like a gravitational lens, making the rays appear to come from those spots

Either way, hopefully in the next 4 years the experts will work out what is going on.

Mysterious Cosmic Rays from Nearby - More Evidence

(Nearby in space terms means hundreds of light years...)

For the last 8 years researchers in Antarctica have been flying a balloon carrying the NASA-funded cosmic ray detector known as the Advanced Thin Ionization Calorimeter. Results have shown that more high-energy cosmic rays are crashing into our atmosphere than expected. Their high-energy indicates that they must come from reasonably close by, for they lose energy over long distances.

Possible sources include dark matter (still theoretical), or "a nearby pulsar, a 'microquasar' or a stellar-mass black hole."

More at NASA

Ultrahigh-Energy Cosmic Rays - Local Origin?

Ultrahigh-energy cosmic rays (UHECRs) are the fastest moving objects ever found. If a ray of light travels through a void for 300 million years, and an UHECR travels on the same journey, light will get there a mere microsecond quicker.

Given the density of microwave radiation thought to fill the voids of space, scientists have been puzzled as to how the UHECRs are hitting Earth at full speed, without being slowed down by radiation (or anything else in their way).

According to Scientific American (April 2008, pages 14-15), the world's largest array of cosmic ray detectors in Argentina has discovered that most UHECRs are coming from nearby galaxies. Strangely none are coming from the Virgo cluster of galaxies, only 60 million light years away.

One of the possible explanations is that super-massive black holes in Virgo are lacking the power of those in other nearby galaxies.

As usual, the super-massive black hole at the center of our own galaxy, and the capacity it may have to bombard us with cosmic rays, is not mentioned.

AGNs - source of high-energy cosmic rays

According to New Scientist, Nov 17 2007:

The Auger researchers analysed all 27 of the most energetic cosmic rays... and found that almost all seemed to come from AGNs less than 250 million light years away...

However... astronomers can't yet rule out the possibility that some high-energy cosmic rays come from gamma-ray bursts

AGNs are Active Galactic Nuclei, of which the nearest is our own Galactic Center - which so far does not appear to spit out cosmic rays, but you'd be foolish to think that this means it won't.

White Dwarf Acts Like A Pulsar

Observers had believed white dwarfs were inert stellar corpses that slowly cool and fade away...At least one white dwarf, known as AE Aquarii, emits pulses of high-energy (hard) X-rays as it whirls around on its axis. "We're seeing behavior like the pulsar in the Crab Nebula, but we're seeing it in a white dwarf," says Koji Mukai of NASA Goddard Space Flight Center in Greenbelt, Md.

...Some white dwarfs, including AE Aquarii, spin very rapidly and have magnetic fields millions of times stronger than Earth's. These characteristics give them the energy to generate cosmic rays.

Found at Space Daily.

(great, more to worry about!)

Retinoids to protect from Cosmic Rays?

Scientific American, November 2007:

NASA has worried that cosmic rays could undermine a human voyage to Mars. New simulations and calculations, though, suggest that such lengthy exposure to space radiation may pose only half the health risk that NASA had expected.

...the lower a proton’s energy, the more damage it does. Apparently, lower-energy protons, which travel more slowly, have more time to interact with tissues. In lowering its assessment of risk, NASA also factored in astronauts’ better-than-average health and switched from “whole-body” radiosensitivity to organ-by-organ measurements, where new studies have found lower risks for lungs, breasts and the blood system.

...Possible drugs include retinoids — vitamins that work as antioxidants — and compounds that delay cell division long enough for damaged cells to repair themselves before they can propagate mutations.

Something to consider storing in your bunker, but it might take some finding.

Cosmic Rays come from AGNs: Confirmed

A group of scientists from 17 countries, formed by researchers of the Universidad de Granada, has proved that the sources of the most energetic particles ever detected do not come from directions uniformly distributed in the firmament, but they aim at areas in which there are galaxies with active nuclei in the centre from a relatively close distance.

....Cosmic rays are protons and atomic nuclei that ride the Universe practically at the speed of light. We are still ignorant of the acceleration mechanisms of particles at energies 100 million times higher than those obtained in the largest particle accelerator in the world.

...Active Galactic Nuclei (AGN) are some of the most violent objects in the Universe. There have been conjectures about its possible link with the production of high energy particles. Scientists think that most of the galaxies present black holes in the centre, with a mass of between one million and thousand million times the solar mass. The one of the Milky Way, our galaxy, has about 3 million solar masses.

Ultimately this news item is telling us that:

a) Cosmic Rays come from AGNs
b) AGNs are some of the most violent objects in the Universe
c) There's an AGN at the heart of our galaxy
d) We don't understand the mechanism

BTW, our AGN is less active than expected. Either it's just a weakling, or it is waiting for its moment to vent...