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How old are we? Debate over the age of the universe just got a bit more complicated – CBC.ca

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Another telescope is helping us better understand the age of the universe and its future.

Using the Atacama Cosmology Telescope (ACT) in Chile, a group of astronomers say their observations support an earlier estimate as to the age of the universe: 13.77 billion years, give or take 40 million years. Their paper was released on the pre-print publishing service arXiv.org on Wednesday and submitted to the Journal of Cosmology and Astroparticle Physics.

The estimate supports observations taken by the European Space Agency’s Planck space telescope in the early 2010s. 

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Over the years, there have been other studies that have disputed that number. For example, in 2019, a study published in the journal Science suggested the universe was 11.2 billion years old.

A portion of a new picture of the oldest light in the universe taken by the Atacama Cosmology Telescope. This part covers a section of the sky 50 times the moon’s width, representing a region of space 20 billion light-years across. (ACT Collaboration)

“For a half dozen years, I’d say even more … within the past three years, there has been one conference after another all over the world completely focused on this issue where one group comes up and they say, ‘Oh, this is what we get,’ and the other group comes up and says, ‘This is what we get,” said Richard Bond, co-author of the paper and director of the Canadian Institute for Theoretical Astrophysics at the University of Toronto.

“We call it the Hubble tension.”

Why isn’t there a clear-cut answer?

It all comes down to the methods used to calculate the expansion of the universe.

Stars vs. the Big Bang

In 1929, astronomer Edwin Hubble found that the universe is expanding. Ever since, scientists have attempted to calculate just how fast that’s occurring. The rate of expansion is called the Hubble Constant.

But the challenge with determining the age of our universe — which in turn helps us better understand not only its past but also its future — is that there are a few methods used to make the calculations.

One involves looking at things that are relatively nearby, cosmologically speaking, such as supernovas (exploding stars) and a particular type of star that varies in brightness, called a Cepheid variable. 

Yet another involves looking far, far back, to a time shortly after the universe came to be — in particular at the cosmic microwave background radiation, or CMB, left over from the rapid birth of the universe, some 380,000 years following the Big Bang.

ACT also used this method, though from a ground-based telescope. But one advantage it had over Planck was the ability to better measure polarization of the CMB, which tells the scientists in what direction the light is moving. This allows it to be more precise.

New physics?

Just how close were their findings to Planck’s?

The space telescope put the rate of the expansion of the universe at 67.5 kilometres per second per megaparsec (one megaparsec is 3.26 million light years). The new findings put that at 67.6 kilometres per second per megaparsec.

“What ACT has done is taken away the option that the CMB measurements were just a fluke of some kind,” said Mark Halpern, a professor at the University of British Columbia’s department of physics and astronomy in Vancouver and co-author of the paper.

This is an important step, the authors say, in trying to determine whether astrophysicists truly understand the universe.

The Atacama Cosmology Telescope in Chile measures the oldest light in the universe, known as the cosmic microwave background. Using those measurements, scientists can calculate the universe’s age. (Debra Kellner)

“If we want the universe to be consistent, then what we need to understand is: [Is] it that we have [something] we haven’t accounted for in any of the measurements? Or is there some kind of new physics?” said Renee Hlozek, co-author and a professor of astrophysics at the Dunlap Institute at U of T’s department of astronomy and astrophysics.

“Because it could be that we’re living in a universe that looks a certain age close to us, but then either the expansion rate changes over time or there’s exotic physics that means it’s a different age.”

Wendy Freedman is an astronomy professor at the University of Chicago’s department of astronomy and astrophysics who was not involved in the study. She also researches the expansion of the universe and has used a particular type of star — a red giant — as a method of calculating the expansion.

“I think it’s a really superb piece of work,” she said of the new paper. “It’s a major study — and looking through the papers, they have paid a huge amount of attention to details and possible uncertainties and errors and run tests and checked through their data.”

Freedman said while the data supports Planck, there’s still something fundamental that we don’t understand, something that the authors themselves acknowledge. 

But with the new ground-based findings, they hope that this will be another piece in the puzzle in an attempt to understand what’s going on in our universe — in particular how it will ultimately cease to be.

“If we understand the age of the universe now, that can actually help us have a better view of how this is going to end,” Hlozek said.

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SpaceX launch marks 300th successful booster landing – Phys.org

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Credit: Unsplash/CC0 Public Domain

SpaceX sent up the 30th launch from the Space Coast for the year on the evening of April 23, a mission that also featured the company’s 300th successful booster recovery.

A Falcon 9 rocket carrying 23 of SpaceX’s Starlink internet satellites blasted off at 6:17 p.m. Eastern time from Cape Canaveral Space Force Station’s Space Launch Complex 40.

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The first-stage booster set a milestone of the 300th time a Falcon 9 or Falcon Heavy booster made a successful recovery landing, and the 270th time SpaceX has reflown a booster.

This particular booster made its ninth trip to space, a resume that includes one human spaceflight, Crew-6. It made its latest recovery landing downrange on the droneship Just Read the Instructions in the Atlantic Ocean.

The company’s first successful booster recovery came in December 2015, and it has not had a failed booster landing since February 2021.

The current record holder for flights flew 11 days ago making its 20th trip off the .

SpaceX has been responsible for all but two of the launches this year from either Kennedy Space Center or Cape Canaveral with United Launch Alliance having launched the other two.

SpaceX could knock out more launches before the end of the month, putting the Space Coast on pace to hit more than 90 by the end of the year, but the rate of launches by SpaceX is also set to pick up for the remainder of the year with some turnaround times at the Cape’s SLC-40 coming in less than three days.

That could amp up frequency so the Space Coast could surpass 100 launches before the end of the year, with the majority coming from SpaceX. It hosted 72 launches in 2023.

More launches from ULA are on tap as well, though, including the May 6 launch atop an Atlas V rocket of the Boeing CST-100 Starliner with a pair of NASA astronauts to the International Space Station.

ULA is also preparing for the second launch ever of its new Vulcan Centaur rocket, which recently received its second Blue Origin BE-4 engine and is just waiting on the payload, Sierra Space’s Dream Chaser spacecraft, to make its way to the Space Coast.

Blue Origin has its own it wants to launch this year as well, with New Glenn making its debut as early as September, according to SLD 45’s range manifest.

2024 Orlando Sentinel. Distributed by Tribune Content Agency, LLC.

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SpaceX launch marks 300th successful booster landing (2024, April 24)
retrieved 24 April 2024
from https://phys.org/news/2024-04-spacex-300th-successful-booster.html

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Wildlife Wednesday: loons are suffering as water clarity diminishes – Canadian Geographic

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The common loon, that icon of northern wilderness, is under threat from climate change due to declining water clarity. Published earlier this month in the journal Ecology, a study conducted by biologists from Chapman University and Rensselaer Polytechnic Institute in the U.S. has demonstrated the first clear evidence of an effect of climate change on this species whose distinct call is so tied to the soundscape of Canada’s lakes and wetlands.

Through the course of their research, the scientists found that July rainfall results in reduced July water clarify in loon territories in Northern Wisconsin. In turn, this makes it difficult for adult loons to find and capture their prey — mainly small fish — underwater, meaning they are unable to meet their chicks’ metabolic needs. Undernourished, the chicks face higher mortality rates. The consistent foraging techniques used by loons across their range means this impact is likely echoed wherever they are found — from Alaska to Canada to Iceland.

The researchers used Landsat imagery to find that there has been a 25-year consistent decline in water clarity, and during this period, body weights of adult loon and chicks alike have also declined. With July being the month of most rapid growth in young loons, the study also pinpointed water clarity in July as being the greatest predictor of loon body weight. 

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One explanation for why heavier rainfall leads to reduced water clarity is the rain might carry dissolved organic matter into lakes from adjacent streams and shoreline areas. Lawn fertilizers, pet waste and septic system leaks may also be to blame.

The researchers, led by Chapman University professor Walter Piper, hope to use these insights to further conservation efforts for this bird Piper describes as both “so beloved and so poorly understood.”

Return of the king

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Giant prehistoric salmon had tusk-like teeth for defence, building nests

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The artwork and publicity materials showcasing a giant salmon that lived five million years ago were ready to go to promote a new exhibit, when the discovery of two fossilized skulls immediately changed what researchers knew about the fish.

Initial fossil discoveries of the 2.7-metre-long salmon in Oregon in the 1970s were incomplete and had led researchers to mistakenly suggest the fish had fang-like teeth.

It was dubbed the “sabre-toothed salmon” and became a kind of mascot for the Museum of Natural and Cultural History at the University of Oregon, says researcher Edward Davis.

But then came discovery of two skulls in 2014.

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Davis, a member of the team that found the skulls, says it wasn’t until they got back to the lab that he realized the significance of the discovery that has led to the renaming of the fish in a new, peer-reviewed study.

“There were these two skulls staring at me with sideways teeth,” says Davis, an associate professor in the department of earth sciences at the university.

In that position, the tusk-like teeth could not have been used for biting, he says.

“That was definitely a surprising moment,” says Davis, who serves as director of the Condon Fossil Collection at the university’s Museum of Natural and Cultural History.

“I realized that all of the artwork and all of the publicity materials and bumper stickers and buttons and T-shirts we had just made two months prior, for the new exhibit, were all out of date,” he says with a laugh.

Davis is co-author of the new study in the journal PLOS One, which renames the giant fish the “spike-toothed salmon.”

It says the salmon used the tusk-like spikes for building nests to spawn, and as defence mechanisms against predators and other salmon.

The salmon lived about five million years ago at a time when Earth was transitioning from warmer to relatively cooler conditions, Davis says.

It’s hard to know exactly why the relatives of today’s sockeye went extinct, but Davis says the cooler conditions would have affected the productivity of the Pacific Ocean and the amount of rain feeding rivers that served as their spawning areas.

Another co-author, Brian Sidlauskas, says a fish the size of the spike-toothed salmon must have been targeted by predators such as killer whales or sharks.

“I like to think … it’s almost like a sledgehammer, these salmon swinging their head back and forth in order to fend off things that might want to feast on them,” he says.

Sidlauskas says analysis by the lead author of the paper, Kerin Claeson, found both male and female salmon had the “multi-functional” spike-tooth feature.

“That’s part of our reason for hypothesizing that this tooth is multi-functional … It could easily be for digging out nests,” he says.

“Think about how big the (nest) would have to be for an animal of this size, and then carving it out in what’s probably pretty shallow water; and so having an extra digging tool attached to your head could be really useful.”

Sidlauskas says the giant salmon help researchers understand the boundaries of what’s possible with the evolution of salmon, but they also capture the human imagination and a sense of wonder about what’s possible on Earth.

“I think it helps us value a little more what we do still have, or I hope that it does. That animal is no longer with us, but it is a product of the same biosphere that sustains us.”

This report by The Canadian Press was first published April 24, 2024.

Brenna Owen, The Canadian Press

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