'Death Star' system to shoot deadly gamma beam at Earth

[Winston Blake]

The good news is that even if it will hit us, we 'probably still have hundreds of thousands of years to come up with a solution'. Like maybe not being here.

Binary 'deathstar' has Earth in its sights
Tuesday, 4 March 2008
by John Pickrell
Cosmos Online

SYDNEY: A spectacular, rotating binary star system is a ticking time bomb, ready to throw out a searing beam of high-energy gamma rays – and Earth may be right in the line of fire.

Astronomers at the University of Sydney, in Australia, first discovered the unusual and beguilingly beautiful star system eight years ago in the Constellation Sagittarius. One member of the pair is a highly unstable star known as a Wolf-Rayet, thought to be the final stage of stellar evolution to precede a cataclysmic supernova explosion.

"When it finally explodes as a supernova, it could emit an intense beam of gamma rays coming our way", said Peter Tuthill, lead researcher of the team that report their findings in the current Astrophysical Journal.

Vast and glowing plume

At a distance of 8,000 light-years from Earth, the pair of stars are a short hop away in galactic terms, and just one quarter of the way to the centre of our Milky Way galaxy.

The researchers took images of the system, known as WR 104, over a period of eight years using Hawaii's Keck Telescope. These images reveal a vast and glowing plume of heated dust and gas, billowing out in a spiral as the stars rotate once every eight months. This 'tail' is up to 30 billion kilometres long.

But something curious about the images caught the attention of the experts.

"Viewed from Earth, the rotating tail appears to be laid out on the sky in an almost perfect spiral. It could only appear like that if we are looking nearly exactly down on the axis of the binary system," said Tuthill.

This means we are peering down the barrel of the gun, as when binary supernovae go off, all their energy is focussed into a narrow beam of wildly destructive gamma ray radiation that emanates (both up and down) from the poles of the system.

"If such a gamma-ray burst happens, we really do not want Earth to be in the way," he said. "I used to appreciate this spiral just for its beautiful form, but now I can't help a twinge of feeling that it is uncannily like looking down a rifle barrel."

Sterilising effect

Though the risk may be remote, there is evidence that gamma ray bursts have swept over the planet at various points in Earth's history with a devastating effect on life.

A 2005 study showed that a gamma-ray burst originating within 6,500 light-years of Earth could be enough to strip away the ozone layer and cause a mass extinction. Researchers led by Adrian Melott at the University of Kansas in Lawrence, U.S., suggest that such an event may have been responsible for a mass extinction 443 million years ago, in the late Ordovician period, which wiped out 60 per cent of life and cooled the planet.

Further research would be required to determine if we are exactly in line with the axis of the system – but even if we are, we probably still have hundreds of thousands of years to come up with a solution, said Tuthill.

Let's hope it didn't commence primary ignition 8001 years ago.

[Brother-Captain Gaius]

Aha - so that's why Holy Terra was moved during the Golden Age of Technology.

First Titan, now this... it's like they knew when they were writing the 40k backstory.

[Zablorg]

The Incredible Hulk is going to have quite a bit of competition in the future.

Near the end it talks about this happening 433 million years ago, killing most of the life on earth and cooling the earth. How does this gamma blast cool the earth exactly?

[Zac Naloen]

The Incredible Hulk is going to have quite a bit of competition in the future.

Near the end it talks about this happening 433 million years ago, killing most of the life on earth and cooling the earth. How does this gamma blast cool the earth exactly?

It wipes away the Ozone layer.

A main component in the Greenhouse effect iirc.

[Molyneux]

The Incredible Hulk is going to have quite a bit of competition in the future.

Near the end it talks about this happening 433 million years ago, killing most of the life on earth and cooling the earth. How does this gamma blast cool the earth exactly?

It wipes away the Ozone layer.

A main component in the Greenhouse effect iirc.

Where on earth did you get that idea?

[CaptainChewbacca]

A GRB that close would convert a significant portion of the atmosphere to nitrogen oxides and deplete about half of the planet's total ozone content. It would be a very painful mass extinction.

[Terralthra]

The Incredible Hulk is going to have quite a bit of competition in the future.

Near the end it talks about this happening 433 million years ago, killing most of the life on earth and cooling the earth. How does this gamma blast cool the earth exactly?

It wipes away the Ozone layer.

A main component in the Greenhouse effect iirc.

Where on earth did you get that idea?

Established science, perhaps?

[Terralthra]

Whoops, linked to the wrong section. This is the correct one.

[Surlethe]

If we have hundreds of thousands of years, chances are we won't be lined up with them anymore when the system ignites, right?

[CaptainChewbacca]

If we have hundreds of thousands of years, chances are we won't be lined up with them anymore when the system ignites, right?

We really have no way of knowing how the star will be turning when it goes off. We could move away, or we could line up for a perfect bullseye.

[cosmicalstorm]

What would happen if our planet was "behind" the sun in respect to that star when it fired?
Would the process be done in a couple of minutes or would it take much longer for it to do damage?

[CaptainChewbacca]

What would happen if our planet was "behind" the sun in respect to that star when it fired?
Would the process be done in a couple of minutes or would it take much longer for it to do damage?

By the time the 'beam' of the burst has propagated out to another star system, it is wide enough that it will hit the ENTIRE system. Even if earth was shielded from the 'front' of the burst, there is an afterglow which would persist for several days to a few weeks and would still do significant damage.

[Turin]

It wipes away the Ozone layer.

A main component in the Greenhouse effect iirc.

Where on earth did you get that idea?

Established science, perhaps?

The ozone layer, which shields us from incoming radiation, is in the stratosphere. Your article is about tropospheric ozone. Tropospheric ozone is actually created by incoming radiation (interacting with carbon-based molecules like fossil fuels). So that's definitely not why gamma radiation would cause cooling.

[Darth Raptor]

The good news is that even if it will hit us, we 'probably still have hundreds of thousands of years to come up with a solution'. Like maybe not being here.

Indeed. If we're still marooned on this fucking rock in a hundred thousand years, we deserve to die.

[Kitsune]

Two questions related to this:
1. It may look like an exact aim at the Sol system but how wide does the stream get. What is the odds of it missing the system
2. If this has happened before, what has been the results?

[Patrick Degan]

Well, gentlemen, we have a few hundred thousand years to consider five options:

• Planetary evacuation

• Moving Earth/the Sol system out of position

• Devising a screen against the radiation wavefront

• Devising a rapid means to regenerate stratospheric ozone

• Die

Free discussion.

[Surlethe]

If we wanted to move the Sun a light-year out of position in, say, 150,000 years, we would need to exert a constant force on the order of 1e20 N for the duration of that time. That does not seem a workable option.

[CaptainChewbacca]

Two questions related to this:
1. It may look like an exact aim at the Sol system but how wide does the stream get. What is the odds of it missing the system

Good.

2. If this has happened before, what has been the results?

Widespread Extinction.

Patrick- I vote for option #4.

[Junghalli]

Well, gentlemen, we have a few hundred thousand years to consider five options:

• Planetary evacuation

• Moving Earth/the Sol system out of position

• Devising a screen against the radiation wavefront

• Devising a rapid means to regenerate stratospheric ozone

• Die

Free discussion.

There is a fifth option: moving the population to underground bunker-habitats for the duration of the crisis.

[CaptainChewbacca]

Well, gentlemen, we have a few hundred thousand years to consider five options:

• Planetary evacuation

• Moving Earth/the Sol system out of position

• Devising a screen against the radiation wavefront

• Devising a rapid means to regenerate stratospheric ozone

• Die

Free discussion.

There is a fifth option: moving the population to underground bunker-habitats for the duration of the crisis.

That'd be the sixth option. Fifth option is 'die'.

[Kodiak]

correct me if I'm wrong, but if the earth is hit by a GRB there will be no "duration of the crisis", the earth will just be totally oblitterated. Sure we could live in artificial structures forever, but I believe the surface of the earth will be totally lost.

[Darth Onasi]

I would think that in a few hundred thousand years we'll have either wiped ourselves out, died from something else or devised an efficient method to travel through space.
If not, then obviously we'll have regressed to cavemen and Earth will be under the rule of those damn dirty apes, and who cares about them?

[Winston Blake]

If we wanted to move the Sun a light-year out of position in, say, 150,000 years, we would need to exert a constant force on the order of 1e20 N for the duration of that time. That does not seem a workable option.

The Shkadov thruster described here would have a thrust of 6.4e17 Nfor a mirror that reflects half the sun's radiation. So the best case is several orders of magnitude too low.

correct me if I'm wrong, but if the earth is hit by a GRB there will be no "duration of the crisis", the earth will just be totally oblitterated. Sure we could live in artificial structures forever, but I believe the surface of the earth will be totally lost.

The article says that Earth has probably survived one in the past, at closer range, with 'only' a 60% loss of life.

[Singular Intellect]

The article says that Earth has probably survived one in the past, at closer range, with 'only' a 60% loss of life.

I'm guessing that the vast majority of remaining 40% of life is the life living in the dark depths of the ocean.

[Fingolfin_Noldor]

If we have hundreds of thousands of years, chances are we won't be lined up with them anymore when the system ignites, right?

There's probably an angle of dispersion to contend with.