Dark skies: a view of the milky way during a meteor shower, Myanmar. Photo: Getty
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Dark energy vs dark matter: a battle of two cosmic monsters

Michael Brooks’s Science Column.

It might be the most prestigious journal in physics, but the Physical Review Letters is no good at teasers. Early in November it published a paper entitled: Indications of a Late-Time Interaction in the Dark Sector. Hardly a great headline for what should have been, in the style of Alien v Predator, “Dark Matter v Dark Energy” – a story of two cosmic monsters locked in eternal conflict.

We believe these monsters exist, but we haven’t seen either of them and we know very little about them. We have suspected the existence of dark matter since 1933, when a Swiss astronomer noticed something odd about the way galaxy clusters spin. They looked like they were being held together by the gravitational pull of invisible matter, which he duly named dark matter. We have been trying to see the stuff ever since, to no avail.

Dark energy is a more recent idea. It, too, comes from astronomical observations, this time of supernovae. A 1998 analysis of the light from these stellar explosions suggested that not only is the universe expanding, but this expansion is getting faster all the time. That can only happen with the help of energy from some unknown source – hence dark energy.

Together, dark energy and dark matter make up 96 per cent of the universe. Now, it turns out, dark energy may be consuming the dark matter.

The discovery came from more observations: this time, of the rate at which cosmic structures form. Dark matter seeds galaxy formation, but galaxies aren’t forming as fast as we would expect. This would make sense if dark matter were disappearing from the universe, but various straightforward explanations for why that might occur have failed to correspond with the observed facts. Now a team of British and Italian researchers has created a computer model that does match the observations. Critical to its success is the idea that dark matter is slowly being converted to dark energy.

According to the simulation, the ingestion of dark matter would be a relatively recent phenomenon, beginning roughly eight billion years ago. If it is really happening, it is important to understand, because our attempts to chart the history of the universe depend on dark matter’s role in forming cosmic structures.

Working from observations of the cosmic microwave background radiation, which came into being roughly 300,000 years after the Big Bang, researchers have shown that the radiation’s distribution through the universe would have seeded long filaments of dark matter. The gravitational pull of these filaments attracted the first atoms of normal matter, gradually creating stars and galaxies in long strings. This is the kind of structure we see now.

Yet if dark energy is slowly taking over from dark matter our previous calculations of cosmic history will have to be corrected. And intriguingly (spoiler alert), it will change our predictions. If dark energy is consuming dark matter, the universe will become dominated by dark energy more quickly than previously thought. That will precipitate an inglorious finale in which dark energy’s repulsive power pushes everything interesting away from us.

Eventually, all the other galaxies will be so far away, and receding so fast, that their light will never reach what remains of our Milky Way. Nearby stars will burn out. Our sun is expected to end its life as a huge single crystal of carbon: a dark diamond in the sky, with no surrounding starlight to make it sparkle.

Afterwards, all the atoms will drift apart and then the fundamental particles of matter will slowly decay to nothing. It’s not a Hollywood ending, but don’t complain that you weren’t warned. 

Michael Brooks holds a PhD in quantum physics. He writes a weekly science column for the New Statesman, and his most recent book is At the Edge of Uncertainty: 11 Discoveries Taking Science by Surprise.

This article first appeared in the 27 November 2014 issue of the New Statesman, The rise of the insurgents

Chicago Daily News
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7 adorably wrong retro visions of the future

With the future looking gloomier than ever, let's take a look at what could have been.

Ah, the future. The golden, glorious future. A time when food will be replaced by pills, walking will be replaced by hovering, and someone will have finally invented a printer that will print your black and white theatre ticket even though (even though!) you have an empty magenta ink cartridge. Who can wait? 

Unfortunately, what with the end-of-the-world-as-we-know-it (see: Trump, Donald J) the future seems less and less spectacular everyday. Is it time to build an underground bunker? Who can say? I can. The answer is yes.

But while you're waiting for your Spaghetti Hoops to heat up in your concrete hidey-hole, you'll need something to read. Here are seven futures that we could have had, if it wasn't for fascism (and also, I guess, the fact that some of these are really dumb).

1. Commuter helicopters

Popular Mechanics (1951) via Flyingcarsandfoodpills.com

What they predicted: Personal helicopters which would transform commuting forever. 

Why it didn't happen: Because apparently Future Us are sufficiently advanced enough to create mini, personal helicopters, but not smart enough to have grasped the concept of a helipad. 

2. Instantly-cookable food

Via Reddit u/Jaykirsch

What they predicted: Food that can be heated or chilled instantly within its packet, by the turn of a knob.

Why it didn't happen: Remember in 2005 when Walkers Worcester Sauce crisps were recalled because it was thought they'd give you cancer? Yeah, that. 

3. Space puppies

Amazing Science Fiction (1958) via Pulparchive.com 

What they predicted: Space puppies. Puppies in space.

Why it didn't happen: Because God enjoys our pain.

4. The "Dinosaur Truck" elevated bus

The Practical Science For Boys And Girls (1949) via Darkroastedblend.com

What they predicted: Buses that could seamlessly glide over cars, carrying us onwards to a new and better future.

Why it didn't happen: It did! China have it. Well done China.

5.  A radio that prints newspapers

Radio Craft (1934) via Tarzan.org

What they predicted: A radio that could print out your morning newspaper, with some kind of nice little red thing on top.

Why it didn't happen: All media is obsolete. You are not even reading these words. Unless you're my mum. Hi mum. 

6. A robot that hits children on the head if they don't listen in class

Computopia (1969) via Pinktentacle.com

What they predicted: A robot that hits children on the head if they don't listen in class.

Why it didn't happen: Whilst our robotics are advanced enough, it turns out so too are our morals. Bummer.

7. Wrist computers

Byte (1981) via archive.org

What they predicted: Little computers that will sit on your wrist, like a watch.

Why it didn't happen: You might be gaping and gawping that someone in 1981 successfully managed to predict the Apple Watch, but you'd be wrong. Take another look - see that tiny keyboard? No one could use that tiny keyboard. What were our ancestors thinking? Idiots. 

Amelia Tait is a technology and digital culture writer at the New Statesman.