Welcome to the dark side. Around 73 percent of the universe is made not of matter or radiation but of a mysterious force called dark energy, a kind of gravity in reverse. Dark energy was listed as the breakthrough of the year in the US journal Science on Dec. 19.
The discovery -- in fact a systematic confirmation of a puzzling observation first made five years ago -- paints an even more puzzling picture of an already mysterious universe. Around 200 billion galaxies, each containing 200 billion stars, are detectable by telescopes. But these add up to only 4 percent of the whole cosmos.
Now, on the evidence of a recent space-based probe and a meticulous survey of a million galaxies, astronomers have filled in at least some of the picture.
ILLUSTRATION: MOUNTAIN PEOPLE
Around 23 percent of the universe is made up of another substance, called "dark matter." Nobody knows what this undetected stuff could be, but it massively outweighs all the atoms in all the stars in all the galaxies across the whole detectable range of space. The remaining 73 percent is the new discovery: dark energy. This bizarre force seems to be pushing the universe apart at an accelerating rate, when gravitational pull should be making it slow down or contract.
"The implications for these discoveries about the universe are truly stunning," said Don Kennedy, the editor of Science. "Cosmologists have been trying for years to confirm the hypothesis of a dark universe."
Martin Rees, Britain's astronomer royal, called it a "discovery of the first magnitude."
The findings were made by an orbiting observatory called the Wilkinson Microwave Anisotropy Probe (WMAP). This measured tiny fluctuations in the cosmic microwave background, in effect the dying echoes of the Big Bang that launched time, space and matter in a tiny universal fireball.
These painstaking measurements were then backed up by the telescopes of the Sloan Digital Sky Survey, which mapped a million galaxies to see how they clumped together or spread out. Both confirmed that dark energy must exist.
The findings settle a number of arguments about the universe, its age, its expansion rate, and its composition, all at once. Thanks to the two studies, astronomers now believe the age of the universe is 13.7 billion years, plus or minus a few hundred thousand. And its rate of expansion is a bewildering 71km per second per megaparsec. One megaparsec is an astronomical measure, totting up to 3.26 million light years. Something latent in space itself is acting as a form of antigravity, exerting a push on the universe, rather than a pull.
Dark matter was proposed more than 20 years ago when it became clear that all the galaxies behaved as if they were far more massive than they seemed to be. All sorts of explanations -- black holes, brown dwarfs and undetectable particles that are very different from atoms -- have been suggested. None has been confirmed.
But dark matter exists, all the same. The dark energy story began in 1998 when astronomers reported that the most distant galaxies seemed to be receding far faster than calculations predicted. A study of a certain kind of supernova confirmed that they had not been misled -- the universe was indeed expanding ever faster, rather than decelerating.
The discovery that some unexpected and undetectable force was pushing the fabric of space apart seemed to confirm a famous observation decades ago by the British scientist JBS Haldane: "The universe is not only queerer than we suppose. It is queerer than we can suppose."
It once again raised profound questions about the nature of the universe: about space, and time, and energy and matter. And it set the theorists on the hunt first for an explanation, and then for an experiment that would confirm their hypothesis.
So they turned once again to the original evidence for the Big Bang, the cosmic microwave background radiation. This is the original blaze of creation, cooled to minus 270℃ -- just about 3℃above absolute zero. Several lines of research, including experiments in the Antarctic and from high-flying balloons, began to provide a clearer picture: the universe simply had to consist of something more than just atoms and so-called dark matter.
"But WMAP, with superbly precise data beamed back from a little spacecraft a million miles away, has made the evidence more precise," said Martin, of the Institute of Astronomy at Cambridge.
"The dark energy is spread uniformly through the universe, latent in empty space. Its nature is a mystery. Whereas there's a real chance of learning what the dark matter is within the next five to 10 years, I'd hold out less hope of understanding the dark energy unless or until there's a unified theory that takes us closer to the `bedrock' of space and time."
In a meeting with Haitian Minister of Foreign Affairs Jean-Victor Harvel Jean-Baptiste on Tuesday, President William Lai (賴清德) vowed to continue providing aid to Haiti. Taiwan supports Haiti with development in areas such as agriculture, healthcare and education through initiatives run by the Taiwan International Cooperation and Development Fund (ICDF). The nation it has established itself as a responsible, peaceful and innovative actor committed to global cooperation, Jean-Baptiste said. Testimonies such as this give Taiwan a voice in the global community, where it often goes unheard. Taiwan’s reception in Haiti also contrasts with how China has been perceived in countries in the region
On April 13, I stood in Nanan (南安), a Bunun village in southern Hualien County’s Jhuosi Township (卓溪), absorbing lessons from elders who spoke of the forest not as backdrop, but as living presence — relational, sacred and full of spirit. I was there with fellow international students from National Dong Hwa University (NDHU) participating in a field trip that would become one of the most powerful educational experiences of my life. Ten days later, a news report in the Taipei Times shattered the spell: “Formosan black bear shot and euthanized in Hualien” (April 23, page 2). A tagged bear, previously released
The world has become less predictable, less rules-based, and more shaped by the impulses of strongmen and short-term dealmaking. Nowhere is this more consequential than in East Asia, where the fate of democratic Taiwan hinges on how global powers manage — or mismanage — tensions with an increasingly assertive China. The return of Donald Trump to the White House has deepened the global uncertainty, with his erratic, highly personalized foreign-policy approach unsettling allies and adversaries alike. Trump appears to treat foreign policy like a reality show. Yet, paradoxically, the global unpredictability may offer Taiwan unexpected deterrence. For China, the risk of provoking the
Starting this month, young women in Denmark would be subject to conscription on the same terms as men. All Danes, regardless of gender, would be required to register for military assessment, and eligible individuals would be selected through a lottery-based draft. In addition, service time would be increased to 11 months, and conscript numbers would grow to meet national defense targets. Denmark is not alone. In the past few years, several European countries, most notably Sweden and Norway, have adopted gender-neutral conscription systems. Latvia is moving in the same direction. The war in Ukraine has accelerated this trend. Faced with the
RSS