New Light On Dark Matter
Down To Earth|November 16, 2020
Scientific research is unearthing new understanding on an old mystery
Akshit Sangomla

Deciphering the true nature of the mysterious dark matter—that constitutes 27 per cent of the Universe—has eluded scientists since it was discovered by Fritz Zwicky in 1933. Dark matter attracts everything through gravity; it competes with the equally mysterious dark energy that pulls apart everything in the Universe. These two competing forces shape the Universe at the largest scale. Dark energy, which constitutes 68 per cent of the Universe, is also the most plausible cause for the observed accelerated expansion of the Universe. This means that all the stars, planets and other celestial bodies—visible to us—make up only 5 per cent of the Universe. The rest is yet unknown. But new scientific evidence is now interpreting this mystery.

To explain current observations of the Universe, scientists say dark matter exists, but it does not emit, absorb or reflect light. This makes it difficult to detect. The only way that its existence can be inferred is through the gravitational pull it exerts on other matter in the form of stars, planets and other celestial objects.

That’s why astronomers look at galaxies and clusters of galaxies—the grandest structures of the Universe—to understand dark matter: what it is and why it exists in the first place. matter, and this increases the dark matter concentration in these clusters.

This, in turn, makes it easier for astronomers to search. Another place scientists have been looking is deep under the Earth’s surface where they have been detecting possible particles that could make up dark matter in Xenon tanks—the largest propellant tank made by humans—and even in rocks.

Two candidates for such particles are the weakly interacting massive particles (WIPS) and axions—a hypothetical elementary particle. In case of Xenon tanks, scientists looked for collisions between WIPS and the central nucleus of the chemically inert Xenon atoms. They observed collisions in the form of tiny light flashes which haven’t been detected as yet.

GAPS AND ANOMALIES ARE MISSING IN OUR UNDERSTANDING OF DARK MATTER AND THEY POINT TO A NEW MODEL, WHICH WILL HAVE MORE EXPLANATORY SCIENTIFIC POWER

SHADES OF NEW EVIDENCE

Continue reading your story on the app

Continue reading your story in the magazine

MORE STORIES FROM DOWN TO EARTHView All

Sting operation

One of India’s worst malaria-affected districts, Malkangiri in Odisha, is on its way to win the fight against this scourge

4 mins read
Down To Earth
December 16, 2020

The great discontent

Farmers delivered the country’s historic harvest bucking the pandemic in 2020. But the year also broke all records of their protests as they demand fair price and access to markets

3 mins read
Down To Earth
December 16, 2020

Fungal attack in apple orchards across the valley

WIDESPREAD FUNGAL infection is set to hit apple production in Kashmir this season.

1 min read
Down To Earth
December 16, 2020

SHRINKING WORLD OF CHANGPAS

The Changpas are trans-Himalayan nomads. For ages, they have roamed the Changthang region of southeastern Ladakh, cut off from the world. Some accounts say they travelled across the Himalayas to arrive here around the 8th century. Located at an altitude of 4,500 metres, life in this arid, vast and rugged plateau is hard. Winters are very long, summers short and vegetation scarce. As a result, the Changpas have led a pastoral life. They rear Changthangi goat, from whose under coat comes the famous pashmina wool. The goats graze on the mountainsides, feeding on seasonal grasses. The weather, however, has changed in the past few decades. The winters and summers are warmer, and there is a perceptive decline in precipitation and snowfall between November and March. This has drastically reduced the size of the grazing grounds and the Changpas now have to shift locations more frequently. RITAYAN MUKHERJEE captures the changing lifestyle of the Changpas

1 min read
Down To Earth
December 16, 2020

Collateral damage

India’s latest plan to save its vultures from dying due to drugs used on cattle offers little hope

3 mins read
Down To Earth
December 16, 2020

PURE TRASH

THE GOVERNMENT’S NEW PROPOSAL ON EXTENDED PRODUCER’S RESPONSIBILITY ON PLASTIC WASTE IS A MOCKERY OF THE COVID-19 REALITY WE FACE TODAY

6 mins read
Down To Earth
December 16, 2020

Gated farming societies

An agritech startup in Bengaluru is helping city dwellers own and manage farms for long-term wealth benefits

2 mins read
Down To Earth
December 16, 2020

2020 Endless Fallouts

COVID-19 has turned the clock back in terms of global health and development indices. The recovery will be long and arduous for a world facing climate change on an unprecedented scale. Indicators are already there that the year ahead will be turbulent

5 mins read
Down To Earth
December 16, 2020

Question Of Ecological Identity

ISHAN KUKRETI speaks to a legislator, an anthropologist and legal experts to make sense of this simmering debate

5 mins read
Down To Earth
December 16, 2020

We need pure honey

It is time we outwitted the business of adulteration. This requires government to act decisively. It needs industry to be made responsible. It needs consumers to be made aware of the purity of the honey they consume. This demands change

6 mins read
Down To Earth
December 01, 2020