Traditional wisdom says that pollutant particles hanging in the air attract moisture, forming thicker clouds that reflect sunlight back into space. Thus, air pollution has a cooling effect, and slows down the effects of global warming. Any move to cut pollution, therefore, was associated with the risk of a rise in global temperatures.

However, the study states that this is not true. The researchers checked satellite data from clouds near sources of pollution: oil refineries, smelters, coal-fired power plants, cities, wildfires and ships. They found that clouds react differently to pollution: while some get thicker, others get thinner. The study says that the aerosol-induced increase in cloud water is partially cancelled by enhanced evaporation of the same cloud water.

This decrease in cloud water offsets 23% of the climate-cooling effect of aerosol-induced increases in the concentration of cloud droplets. Therefore, the study states, increases in cloud water do not result in substantial climate cooling effect.

This landmark study paves the way for a more realistic understanding of pollution’s role in climate cooling. Besides being bad for our health, air pollution does not significantly reduce global warming, and not tackling it immediately could have far worse consequences.

Washington: Astronomers have created the most precise map to date of the Milky Way by tracking thousands of big pulsating stars spread throughout the galaxy, demonstrating that its disk of myriad stars is not flat but dramatically warped and twisted in shape.

The researchers on Thursday unveiled a three-dimensional map of the Milky Way – home to more than 100 billion stars including our sun – providing a comprehensive chart of its structure: a stellar disk comprised of four major spiral arms and a bar-shaped core region.

“For the first time, our whole galaxy – from edge to edge of the disk – was mapped using real, precise distances,” said University of Warsaw astronomer Andrzej Udalski, co-author of the study published in the journal Science.

Until now, the understanding of the galaxy‘s shape had been based upon indirect measurements of celestial landmarks within the Milky Way and inferences from structures observed in other galaxies populating the universe. The new map was formulated using precise measurements of the distance from the sun to 2,400 stars called “Cepheid variables” scattered throughout the galaxy.

“Cepheids are ideal to study the Milky Way for several reasons,” added University of Warsaw astronomer and study co-author Dorota Skowron. “Cepheid variables are bright supergiant stars and they are 100 to 10,000 times more luminous than the sun, so we can detect them on the outskirts of our galaxy. They are relatively young – younger than 400 million years – so we can find them near their birthplaces.”

The astronomers tracked the Cepheids using the Warsaw Telescope located in the Chilean Andes. These stars pulsate at regular intervals and can be seen through the galaxy‘s immense clouds of interstellar dust that can make dimmer stellar bodies hard to spot.

The map showed that the galaxy‘s disk, far from flat, is significantly warped and varies in thickness from place to place, with increasing thickness measured further from the galactic centre. The disk boasts a diameter of about 140,00 light years. Each light year is about 6 trillion miles (9 trillion km).

The Milky Way began to form relatively soon after the Big Bang explosion that marked the beginning of the universe some 13.8 billion years ago. The sun, located roughly 26,000 light years from the supermassive black hole residing at the centre of the galaxy, formed about 4.5 billion years ago.

The super-Earth planet – named GJ 357 d -was discovered in early 2019 owing to NASA’s Transiting Exoplanet Survey Satellite (TESS), a mission designed to comb the heavens for exoplanets, according to the research published in the Astrophysical Journal Letters. “This is exciting, as this is humanity’s first nearby super-Earth that could harbour life -uncovered with help from TESS, our small, mighty mission with a huge reach,” said Lisa Kaltenegger, associate professor of astronomy at Cornell University in the US and a member of the TESS science team.

The exoplanet is more massive than our own blue planet, and Kaltenegger said the discovery will provide insight into Earth’s heavyweight planetary cousins. “With a thick atmosphere, the planet GJ 357 d could maintain liquid water on its surface like Earth, and we could pick out signs of life with telescopes that will soon be online,” she said.

Astronomers from the Institute of Astrophysics of the Canary Islands and the University of La Laguna, both in Spain, announced the discovery of the GJ 357 system in the journal Astronomy & Astrophysics. They showed that the distant solar system – with a diminutive M-type dwarf sun, about one-third the size of our own sun -harbours three planets, with one of those in that system’s habitable zone: GJ 357 d. Last February, the TESS satellite observed that the dwarf sun GJ 357 dimmed very slightly every 3.9 days, evidence of a transiting planet moving across the star’s face. That planet was GJ 357 b, a so-called “hot Earth” about 22 per cent larger than Earth, according to the NASA Goddard Space Flight Center, which guides TESS. Follow-up observations from the ground led to the discovery of two more exoplanetary siblings: GJ 357 c and GJ 357 d.