Cover Stories

Is dark matter mystery about to be solved?

8 March 2008
New Scientist issue 2646
I share the cover story on this week’s New Scientist.  My article explores the nature of dark matter, whilst Amanda Gefter’s companion piece explores the nature of dark energy.  Here’s the introduction to the two articles:
     “As far as most of the universe is concerned, you're inconsequential. The everyday stuff that constitutes you and everything you care about makes up just 4 per cent of the cosmos; the rest we call dark matter and dark energy. What they actually are, though, is anyone's guess. Now we may be on the verge of enlightenment. In this article, we report how experiments are getting ready to identify dark matter, while on page 32 we consider why dark energy may be an illusion created by our place in space. Be prepared for a new cosmic order...”
     And here is the introduction to my article:
     “THIS YEAR, there's a good chance that a sizeable chunk of our universe will turn up. A fair bit of the cosmos - 22 per cent of it, in fact - seems to be made of invisible dark matter, whose extra gravity helps to bind stars together in galaxies, and galaxies together...”
The complete article is 2511 words long and is available here; a subscription is required.

Unlocking Mercury's secrets

5 January 2008
New Scientist issue 2637

OF ALL the planets in our solar system, Mercury is an enigma. The chimeric planet has a face like the moon, yet conceals a metal heart larger than that of Mars; while all of the major planets go around the sun in more or less the same plane, Mercury opts for a jaunty angle; while Earth's orbit is essentially round, Mercury prefers an ellipse; and let's not forget the magnetic field that it shouldn't have. Clearly, the closest planet to the sun is trying to tell us something.
    It even had a famous fan: Albert Einstein. Mercury's odd motion around the sun was impossible to explain with Newton's theory of gravitation alone. The puzzle remained until Einstein used it as the first convincing evidence for his general theory of relativity.
    Now astronomers think it holds another secret: how the solar system itself was formed. Ralph McNutt, a planetary scientist at...”

The complete article is 2762 words long and is available here
(a subscription is required).

The Sun: diary of a death

BBC Focus March 2007

Every day we take the warmth and light of our Sun for granted. But what if we were to discover that this plentiful font of energy was dying? That’s the premise behind Sunshine, a new film by Danny Boyle in which an intrepid band of astronauts head off to save the Sun and mankind from an early grave.

Thankfully, it is all fiction. Astronomers are confident that the Sun is not going to peg out for another five or even six billion years. Go back just two hundred years though, and astronomers were almost totally in the dark.

Read the extended version of the article for free here.

Cover reproduced with permission from BBC Focus magazine

Dark energy: Seeking the heart of darkness

16 February 2007
New Scientist issue 2591

Every now and again cosmologists decide that the universe needs redecorating. Sometimes they declutter, as when Copernicus and Kepler shuffled the sun and the Earth to get rid of all those epicycles and make the planets move in straightforward orbits. Sometimes they embellish, as when Einstein decided that there's more to space than good old-fashioned nothingness, and introduced the concept of a deformable space-time.

They are at it again, but this time it's different. Like the decorator who strips away a layer of wallpaper to reveal a crumbling wall, cosmologists are realising that their findings point to serious problems with their models of the structure of the universe. This discovery is forcing them to contemplate bold changes to fix the damage.

When they are done, chances are we will hardly recognise the old place. "It will repaint not only our picture of the universe but perhaps particle physics, gravitational physics ...
The complete article is 3374 words long and is available here
(a subscription is required).

Gravity's secret

11 November 2006
New Scientist issue 2577

It's a twist that not even Einstein expected. Large masses may exert a swirling influence when they rotate

GRAVITY has a secret side. As well as the brute force that holds us to the ground, large masses should also exert a subtle swirling influence when they rotate, a force called gravitomagnetism. It's so faint that a NASA spacecraft called Gravity Probe B has been orbiting the Earth for over two years to accrue enough evidence to have a chance of confirming this force.

Yet in a lab in Austria, Martin Tajmar and his team have already succeeded in detecting a faint signal that seems to be due to this elusive component of gravity. A reason for celebration? Not quite. Puzzlingly, the force they seem to have generated is vastly more powerful than anyone else expected.

Despite its name, gravitomagnetism has nothing to do with magnetic fields as we think of them. According to Einstein's general theory of relativity, a rotating mass such as a planet should twist the ...

The complete article is 2545 words long and is available here
(a subscription is required).

Global warming: Will the Sun come to our rescue?

18 September 2006
New Scientist issue 2569

It is known as the Little Ice Age. Bitter winters blighted much of the northern hemisphere for decades in the second half of the 17th century. The French army used frozen rivers as thoroughfares to invade the Netherlands. New Yorkers walked from Manhattan to Staten Island across the frozen harbour. Sea ice surrounded Iceland for miles and the island's population halved. It wasn't the first time temperatures had plunged: a couple of hundred years earlier, between 1420 and 1570, a climatic downturn claimed the Viking colonies on Greenland, turning them from fertile farmlands into arctic wastelands.

Could the sun have been to blame? We now know that, curiously, both these mini ice ages coincided with prolonged lulls in the sun's activity - the sunspots and dramatic flares that are driven by its powerful magnetic field.

Now some astronomers are predicting that the sun is about to enter another quiet period. ...

The complete article is 2814 words long and is available here
(a subscription is required).

Is this planet 10?

Astronomy Now September 2005

It’s larger than Pluto.  In fact, it’s the largest object found in the Solar System for more than 150 years.  ‘Planet 10’, or 2003 UB313, sits three times further away from the Sun than Pluto and could herald a bonanza of new planets to be discovered.  But, will the International Astronomical Union (IAU) call it a planet?  Stuart Clark investigates.

Read the rest of the article for free here.

Global dimming

BBC Focus August 2005

Next time you see the white and orange livery of an Easyjet flight overhead, resist the urge to wince at the memory of the scrum-down for seats.  Instead, spare a charitable thought; Easyjet and the other short-haul, low-cost flight companies may be helping to save the planet.

“Short haul flights are damaging on fuel but seldom do they get high enough to form contrails,” says Dr Robert Noland of Imperial College, who investigates the environmental effects of air travel.

A contrail, short for condensation trail, forms when hot, humid air created in a jet engine mixes with the surrounding, low pressure, cold air of the atmosphere.  Generally, the higher the altitude, the colder the air and the more likely contrail formation becomes.  It’s similar to the way your breath condenses into a vaporous cloud on a cold day.

The more short-haul flight companies there are, taking up slots at airports that traditional airlines would like to use for the more lucrative high altitude long-haul flights, the fewer contrails will appear in the sky.

Because they are essentially clouds, contrails have traditionally been thought to help trap warmth and exacerbate global warming.  Now they are being implicated in another, seemingly contradictory but equally important, climate change effect: global dimming.

Read the full article for free here.

Cover reproduced with permission from BBC Focus magazine

Far-out worlds,
just waiting to be found

23 July 2005
New Scientist issue 2509

In the dark reaches of the solar system lurk swarms of hidden worlds. Too small and too distant to reflect sunlight, they have remained under the cover of darkness for billions of years. But now the outer solar system is giving up its secrets. And with them comes an astonishing claim: "It's quite possible that there is a halo of planets surrounding our solar system, just waiting to be found," says Eugene Chiang, an astronomer at the University of California, Berkeley.

What makes Chiang's claim so surprising is the sheer number and size of these planets. Weighing more than Mars, they dwarf Sedna and Quaoar, the largest rocky bodies spotted circling the sun beyond Pluto.

The evidence comes from a source closer to home: the discovery of a 100-kilometre lump of ice and rock circling the sun in the same orbit as Neptune. This frigid asteroid was chalked up as ...

The complete article is 2642 words long and is available here
(a subscription is required).

Six ways to save the planet

Focus March 2005

It’s a question of ‘when’ not ‘if’ – that’s the expert opinion on the detection of an Earth-bound asteroid or comet.  Somewhere, out in space, a kilometre-sized lump of rock could be inexorably edging closer to Earth.  Or a similarly sized iceberg could be making its fateful plunge from the depths of space.

NASA is scheduled to launch a quick and dirty mission called Deep Impact on 6 January 2005.  It will smash into a comet, revealing its interior, thereby providing clues about the structure of these deep space menaces.

In preparation for when the doomsday object is found, Stuart Clark looks at the options scientists are considering to save the planet.

Read the full article for free here.

Cover reproduced with permission from Focus magazine

The bubble that ate the universe

12 March 2005
New Scientist issue 2490

Throughout the universe, space-time is fizzing. Bubbles pop in and out of existence across the cosmos. Mostly, the froth is harmless. Yet at any moment, it could unleash a catastrophic reaction that rips through the fabric of space, destroying the universe and everything in it.

Clearly, a killer bubble hasn't formed so far in the 13 billion years since the universe began. Yet Louis Clavelli believes that space-time bubbles are ripping stars apart on a daily basis. If he is right, the universe is a more dangerous place than you might think.

It's a controversial idea. Most astronomers deny that anything as exotic is responsible for ripping stars apart. But Clavelli, who works as a physicist at the University of Alabama in Tuscaloosa, insists that his findings come from reputable physics.

The idea of a frothy universe springs from the view that space can exist in a number of different ...

The complete article is 2418 words long and is available here.
(a subscription is required)

Voyage to the ringed planet

Focus July 2004

Since the world’s first glimpse of Saturn through a telescope, this far-flung planet has enchanted mankind with its beauty.  The rings of Saturn are spectacular enough when seen in photographs. When seen with the naked eye through a telescope of any size, they almost defy belief. Yet, since the Voyager 2 flyby of 1981, spacecraft have neglected the planet.  Now the twenty-three-year wait is over.  After a seven-year voyage through deep space, the joint NASA-ESA Cassini-Huygens mission is due to arrive.  It promises to revolutionise our understanding of the giant planet.

Read the full article for free here.

Cover reproduced with permission from Focus magazine

Ice-age Earth

Focus June 2004

According to filmmaker Roland Emmerich, 28 May is the day Earth plunges into a new ice age.  That, at least, is the date when his new glacier-laden movie, The Day After Tomorrow, hits cinemas to tell the grim tale of mankind’s struggle with the approaching ice sheets.

Doubtlessly many people will leave the movie theatres comforted by the fact that it is a just a flight of fancy.  But is it?  During the past two million years, there have been twenty ice ages.  The total time that the Earth has spent in these cold snaps is a staggering 1,800,000 years (90% of the period).  We are incredibly lucky, it would seem, to be alive in an era of such clemency.

Read the full article for free here.

Cover reproduced with permission from Focus magazine

Space particles play with the mind

28 May 2008
New Scientist issue 2658

“It’s hardly unusual to find things flashing into your head as you fall asleep, but as Christer Fuglesang was settling down on his first night aboard the International Space Station it happened quite literally. It was December 2006, and as the European Space Agency astronaut floated, eyes closed, in his sleeping bag he suddenly saw a spot of white light surrounded by a faint halo. It vanished in an instant but Fuglesang realised immediately what it was. "I had heard about these things and so was very happy to have finally experienced one," he says.

Since Buzz Aldrin and Neil Amstrong first reported these flashes during the Apollo 11 mission to the moon in 1969, dozens of astronauts have seen them. An investigation by NASA after Apollo 11 returned concluded that the flashes, sometimes called "phosphenes", were a consequence of fast-moving particles, most probably cosmic rays, ...”

The complete article is 1619 words long.  You can read the full version here but a subscription is required.

23 May 2008
New Scientist issue 2657

“SINCE the Viking orbiters beamed back the first tantalising images of water-cut features on Mars in the 1970s, NASA's mantra for the Red Planet has been simple: "follow the water". Working out when Mars had liquid water on its surface, and where that water went, they reason, will provide vital clues about whether Mars could once have harboured life, and whether life could cling on today.

Since then a long line of orbiters, landers and rovers have searched the Martian surface for signs of where water once flowed. The latest, NASA's Phoenix lander, is scheduled to reach the surface of Mars on 25 May. If all goes well, it could be the first lander to actually hold Martian water in its robotic hands, and will answer. …”

The complete article is 2154 words long.  You can read the full version here but a subscription is required.

The trouble with supernovae

25 October 2007
New Scientist issue 2627

“IN NOVEMBER 1572, a dazzling new star appeared in the night sky. It became so bright so quickly that it soon outshone everything except the sun and the moon and could even be seen in daylight.

Danish astronomer Tycho Brahe tracked the star for 16 months. As it slowly faded, the star changed colour from white to yellow then orange and finally faint red.

We now know that what Brahe saw was probably a type Ia supernova, a species of exploding star that, over the past 30 years, has become increasingly important in astrophysics. Because they are all thought to explode with the same brightness, type Ia supernovae are used as "standard candles" to gauge distances across the universe.

But type Ia supernovae are beset with problems. It has become clear that they do not all explode with the same brightness. What's more, though astronomers were once sure they knew...”

On the hunt for cosmic fossils

16 May 2007
New Scientist issue 2604

When it comes to galaxies, astronomers have a lot in common with Victorian fathers. They have a pretty good idea of what is involved in their conception and they know what the end product looks like. But the actual birth itself is a total mystery.

Using optical telescopes, astronomers can peer back through space to a time around 1 billion years after the big bang. Even at this early stage there are galaxies, not as fully grown as the ones today, but recognisable as galaxies nonetheless.

To look back further in time means studying microwaves rather than light, and that's when we lose sight of galaxies altogether. Instead, we see a universal bath of radiation that carries the imprint of the way the universe looked just 300,000 years after the big bang. At that point in cosmic history, there were no galaxies - just rippling undulations in the density of...

Cannibal star:
first sighting of a celestial glutton

05 April 2007
New Scientist, issue 2598

Were our eyes sensitive to infrared light, 2002 would have been a banner year for sky watchers. It would be remembered as the year a new star appeared in the sky. A star so bright that it was visible even in the daytime.

As it was, the limitations of human eyesight meant that only astronomers with specialist equipment could watch this extraordinary event. At first, they did not even recognise it as anything special, believing that the appearance of a new star signalled a run-of-the-mill astronomical event called a nova. Then things got weird - very weird.

Astronomers watched agog as the star flared up again and again, changed colour from white to red and then disappeared from view only to reinvent itself as an infrared star that was brighter than the daylight sky. At this point, it displayed such peculiar properties that astronomers had to confess that they didn't ...

The complete article is 2659 words long and is available here
(a subscription is required).

In August 2006, Stuart Clark visited several astronomical sites in Chile, courtesy of the UK’s Particle Physics and Astronomy Research Council (now the Science and Technology Facilities Council. He wrote three articles about his visit for Astronomy Now.

Part one: The discovery machine

November 2006
Astronomy Now

ESO’s Very Large Telescope is a vast discovery machine in the Chilean desert. Stuart Clark visited the Very Large Telescope and came back Very Impressed.

There is nothing ordinary about the VLT. Sitting on Cerro Paranal in Chile, 2,635 kilometres above sea level, it is located in one of the driest places on the Earth: the Atacama desert, in the foothills of the Andes. It is about a thirty-hour journey from England involving multiple flights and a final, gut-wrenching drive through the deep desert. …

Read the full article for free here.

Part two:
Improving the VLT

December 2006
Astronomy Now

How do you improve the world’s largest telescope?  Stuart Clark visited the Very Large Telescope in Chile to find out.

The European Southern Observatory (ESO) continues to grow. The UK joined ESO in 2002. Now Spain has signed on, as well. As the ESO roster enlarges, so too does its ambition. There are now a number of plans for future telescopes and observatories but firstly, the VLT itself is in the process of being enlarged. If successful, the ESO team will be able to simulate a single telescope of over a 100 metres in diameter. …

Read the full article for free here.

Part three:
Halfway to space

January 2007
Astronomy Now

In ten years time, the European Southern Observatory will have turned the barren Chajnantor Plateau in Chile into one of the most important astronomical observatories in the world. Stuart Clark visited the world’s highest construction site.

It is hard to believe that this arid, airless place will be so important to astronomers in the future. At the moment there is just one lonely radio dish and some half finished buildings but the excitement of the astronomers and engineers that work here is infectious. At just over 5,000 metres altitude, there is about half the oxygen as at sea level. “I often say that up here, you are halfway to space,” says John Richer, University of Cambridge.

Read the full article free here.

Have we got
gravity all wrong?

03 June 2006
New Scientist issue 2554

Slava Turyshev is a man on a mission. Two missions in fact. The researcher from NASA's Jet Propulsion Laboratory in Pasadena, California, is about to re-fly the two most controversial spacecraft in history. The Pioneer 10 and 11 probes were launched in 1972 and 1973 and are now drifting in deep space beyond the outermost planets of the solar system. NASA lost contact with Pioneer 10 in 2003, but though the probes are now long gone, they are anything but forgotten. That's because Pioneer 10, when last heard from, seemed to be off course by around 400,000 kilometres and nobody has ever been able to figure out why. Did some malfunction nudge the craft off its expected trajectory, or are there deeper forces at work?

Pioneer 10's sister ship is also being pushed off course, and an analysis of the Galileo spacecraft to Jupiter and the Ulysses solar probe hints ...

The complete article is 2377 words long and is available here
(a subscription is required).