adplus-dvertising
Connect with us

Science

The Galapagos Islands Will Be a Cool Refuge in a Warming World – Hakai Magazine

Published

 on


Article body copy

Pushed by climate change, almost every part of the ocean is heating up. But off the west coast of the Galapagos Islands, there is a patch of cold, nutrient-rich water. This prosperous patch feeds phytoplankton and breathes life into the archipelago.

“The cool water sustains populations of penguins, marine iguanas, sea lions, fur seals, and cetaceans that would not be able to stay on the equator year round,” says Judith Denkinger, a marine ecologist at the Universidad San Francisco de Quito in Ecuador.

Over the past four decades, this cold patch has cooled by roughly half a degree. Its persistence has scientists wondering how long it will hold. The Galapagos Islands are already famed for their biodiversity. Could it be that the water offshore will become a refuge for marine animals seeking cold water in a warming world? The answer, it seems, is yes. At least for a while.

300x250x1

There are other cold pools on the planet. One, in the North Atlantic just south of Greenland, is caused by the weakening of a global current that carries heat north. But according to a new study led by Kris Karnauskas and Donata Giglio, climate scientists at the University of Colorado Boulder, the Galapagos cold pool is a product of the shape of the seafloor and the rotation of the planet—two things unlikely to change because of rising greenhouse gases. And the Galapagos are not the only islands seeing this effect.

Along the equator, several islands have unusually cold water lying immediately to their west. According to Karnauskas and Giglio’s work, this cooling is the product of upwelling caused by the collision of a deep ocean current against the islands lying in its path.

Analyzing 22 years’ worth of ocean temperature data collected by Argo floats, along with observations from satellites, ocean gliders, and cruises, the scientists constructed temperature profiles around several equatorial islands and pinpointed the location of the Equatorial Undercurrent (EUC), a cold, fast-flowing current that travels eastward about 100 meters below the surface of the Pacific Ocean. The EUC is held in place along the equator by the Coriolis force, an inertia brought on by the Earth’s spin on its axis. This same effect twists hurricanes anticlockwise north of the equator and clockwise south of it.

Karnauskas and Giglio’s work shows that when the EUC gets within 100 kilometers west of the Galapagos Islands, it suddenly intensifies as it’s diverted upward by the islands. This causes the water to be up to 1.5 °C cooler than the water outside this cold pool. The researchers found a similar, yet weaker, effect west of the Gilbert Islands in the western Pacific Ocean.

In a separate study, Karnauskas shows that over the past few decades, the EUC has been getting stronger and deeper. It’s also moved about 10 kilometers south, bringing its path more in line with the Galapagos Islands. All of those changes contribute to the observed cooling, says Karnauskas.

For the Galapagos marine ecosystem, this cooling is “a bit of a mixed bag,” says Jon Witman, a marine ecologist at Brown University in Rhode Island who was not involved in the studies. “The cool upwelled water of the EUC certainly has important positive impacts,” he says. But when combined with other oceanic processes that also cause temperatures to drop, such as La Niña, the cooling can hurt certain wildlife, such as by cold shocking corals, causing them to bleach and sometimes die.

For the near future, this shield of cold will likely benefit life around the Galapagos Islands and other equatorial islands. But this cooling water is fighting a losing battle with a warming atmosphere, says Karnauskas. “This cooling trend probably won’t last through the century; it will eventually be overwhelmed,” he says.

If some species are protected at least for a while, however, the Galapagos could become a genetic bank that could be used to reseed devastated marine ecosystems elsewhere, suggests Karnauskas. “And it’s just beautiful that it’s the iconic Galapagos that we’re talking about here.”

Adblock test (Why?)

728x90x4

Source link

Continue Reading

Science

An asteroid will whip by Earth tomorrow in one of closest approaches ever recorded

Published

 on

An asteroid the size of a delivery truck will whip past Earth on Thursday night, one of the closest such encounters ever recorded.

NASA insists it will be a near miss with no chance of the asteroid hitting Earth.

The U.S. space agency said Wednesday that this newly discovered asteroid will zoom 3,600 kilometres above the southern tip of South America. That’s 10 times closer than the bevy of communication satellites circling overhead.

The closest approach will occur at 7:27 p.m. ET.

300x250x1

Even if the space rock came a lot closer, scientists said most of it would burn up in the atmosphere, with some of the bigger pieces possibly falling as meteorites.

NASA’s impact hazard assessment system, called Scout, quickly ruled out a strike, said its developer, Davide Farnocchia, an engineer at the agency’s Jet Propulsion Laboratory in Pasadena, Calif.

“But despite the very few observations, it was nonetheless able to predict that the asteroid would make an extraordinarily close approach with Earth,” Farnocchia said in a statement.

“In fact, this is one of the closest approaches by a known near-Earth object ever recorded.”

Asteroid spotted by amateur astronomer in Crimea

Discovered Saturday, the asteroid known as 2023 BU is believed to be 3.5 to 8.5 metres across.

It was first spotted by Gennady Borisov, the same amateur astronomer in Crimea who discovered an interstellar comet in 2019.

Within a few days, dozens of observations were made by astronomers around the world, allowing them to refine the asteroid’s orbit.

The asteroid’s path will be drastically altered by Earth’s gravity once it zips by. Instead of circling the sun every 359 days, it will move into an oval orbit lasting 425 days, according to NASA.

728x90x4

Source link

Continue Reading

Science

Nuclear-powered spaceships? U.S. plans for 2027

Published

 on

WASHINGTON –

The United States plans to test a spacecraft engine powered by nuclear fission by 2027 as part of a long-term NASA effort to demonstrate more efficient methods of propelling astronauts to Mars in the future, the space agency’s chief said on Tuesday.

NASA will partner with the U.S. military’s research and development agency, DARPA, to develop a nuclear thermal propulsion engine and launch it to space “as soon as 2027,” NASA administrator Bill Nelson said during a conference in National Harbor, Maryland.

The U.S. space agency has studied for decades the concept of nuclear thermal propulsion, which introduces heat from a nuclear fission reactor to a hydrogen propellant in order to provide a thrust believed to be far more efficient than traditional chemical-based rocket engines.

300x250x1

NASA officials view nuclear thermal propulsion as crucial for sending humans beyond the moon and deeper into space. A trip to Mars from Earth using the technology could take roughly four months instead of some nine months with a conventional, chemically powered engine, engineers say.

That would substantially reduce the time astronauts would be exposed to deep-space radiation and would also require fewer supplies, such as food and other cargo, during a trip to Mars.

“If we have swifter trips for humans, they are safer trips,” NASA deputy administrator and former astronaut Pam Melroy said Tuesday.

The planned 2027 demonstration, part of an existing DARPA research program that NASA is now joining, could also inform the ambitions of the U.S. Space Force, which has envisioned deploying nuclear reactor-powered spacecraft capable of moving other satellites orbiting near the moon, DARPA and NASA officials said.

DARPA in 2021 awarded funds to General Atomics, Lockheed Martin and Jeff Bezos’ space company Blue Origin to study designs of nuclear reactors and spacecraft. By around March, the agency will pick a company to build the nuclear spacecraft for the 2027 demonstration, the program’s manager Tabitha Dodson said in an interview.

The joint NASA-DARPA effort’s budget is US$110 million for fiscal year 2023 and is expected to be hundreds of millions of dollars more through 2027.

Reporting by Joey Roulette; Editing by Chizu Nomiyama and David Gregorio

728x90x4

Source link

Continue Reading

Science

The green comet ZTF returns to the solar system 50,000 years later… and it will be visible from Earth

Published

 on

For astronomy enthusiasts, February 1 is marked in red on their calendars. The reason: it is not every day that there is a chance to see a green comet.

In fact, it is the first time in 50,000 years that C/2022 ZTF will return to the solar system. And it will be early next month when it will reach its closest position to Earth.

Specifically, the green comet ZTF will pass 42 million light years from our planet. Experts are not 100 percent sure whether it will be visible from the surface without the use of any instrument. However, if we have specific astronomy binoculars or telescopes, we will be able to see it without any problem.

As usually happens in these cases, the best places to observe the comet, this one or any other, are places with little artificial light. That is to say, we should move away from urban centres and it is preferable to do so in the hours before dawn.

300x250x1
Un cometa brillante, visto desde California.Getty

Why is comet ZTF green?

Comet ZTF has a brightness and a colour that, although not unique, is clearly distinctive. Its hue is due to the fact that it is composed, among other materials, of diatomic carbon.

When it comes into contact with sunlight, the decomposition of this element causes the gas to acquire this spectacular colour.

Comet ZTF was discovered in March 2022

Un telescopio apunta al cielo.
Un telescopio apunta al cielo.Getty

Frank Masci and Bryce Bolin of the Palomar Observatory in California were responsible for spotting the striking comet ZTF in the sky. It is so named because its discovery is part of the Zwicky Transient Facility surveillance programme, which uses the powerful Schmidt telescope at the facility.

Initially, the scientists responsible for the discovery thought it was an asteroid, but they quickly realised that this was not the case. Despite the striking colour of this comet, experts advise keeping expectations low. In any case, it is an event that has aroused great interest in the community.

728x90x4

Source link

Continue Reading

Trending