Connect with us


Massive Webb Telescope May See Close to the Beginning of Time – BNN



(Bloomberg) — The largest, most expensive and most sophisticated space telescope ever made is scheduled to lift off Dec. 25 from the north coast of South America. At its eventual orbital station 932,000 miles from Earth, the James Webb Space Telescope might just see to the beginning of time.

The farther one looks in space, the further back in time one goes. When Webb begins its work in mid-2022, it will help scientists study some of the earliest light in the universe and to peer more closely at planets in other galaxies. More than 30 years after NASA launched the Hubble Space Telescope, its much bigger successor is designed to see through the most ancient mists of deep space.

The almost $11 billion telescope, more than two decades in the making, is a National Aeronautics and Space Administration collaboration with the European and Canadian space agencies. It’s currently scheduled to launch early on Dec. 25 from the European Space Agency’s South American spaceport in French Guiana aboard an Ariane 5 rocket.

For science, the Webb telescope’s ultimate promise is a greater understanding around two fundamental questions for humanity: Where did we come from and are we alone? But for NASA, it’s also a huge risk given everything that might go wrong.

The telescope is “a shining example of what we can accomplish when we dream big,” NASA Administrator Bill Nelson said Dec. 21 at a pre-launch briefing, calling it “one of the great engineering feats for the people of this planet.”

The Webb telescope will examine the infrared spectrum—thermal radiation humans can’t see and which is often obscured to ground-based telescopes. Hubble is still working, albeit from an orbit much closer to Earth (340 miles away), collecting data in the visible light spectrum. The older telescope, which had to be repaired after launch because of a flaw in its mirror, has been repeatedly updated with new technology and could last another two decades.

But researchers say Webb, named for NASA’s administrator during its heyday of the Mercury, Gemini and Apollo rocket programs in the 1960s, is crucial to a deeper understanding of the early universe and how stars and galaxies formed. New insights are expected from discoveries dating back 13.5 billion years, only a few hundred million years after the Big Bang. The Webb will also be able to peer more closely at objects first uncovered by Hubble, many of which are obscured by interstellar dust and gas that the newer telescope can pierce.

The Webb’s skillset will also include observation of planets—some possibly like Earth—that orbit stars in other galaxies. One Webb target is the Andromeda galaxy, the closest to our Milky Way, which reveals far more of its nature in the infrared spectrum than in visible light. The telescope also has multiple forms of spectrograph imaging to study the composition of stars and planets.

But before any of this research can happen, Webb must arrive on station. First, the launch itself must be successful. Then the telescope must execute a daunting series of maneuvers, with the first 13 hours of flight including two critical tasks. Roughly 33 minutes after liftoff, Webb must deploy its solar array to begin generating power. Then about 12 hours later, the craft must initiate a course-correction rocket burn to fine-tune its trajectory toward its final destination.

Both must happen precisely on cue, long before Webb completes the 29-day trip to its post. 

The telescope’s workstation is called the second Lagrange point, of L2, “behind” the Earth as viewed from the sun. The spot is one of five such points where the gravity of the sun and Earth balance to allow a spacecraft to move along with them. This reduces the amount of propellant needed for the craft to maintain its orbit.

The dark and cold of space are integral to Webb’s infrared work. After rolling out its solar array, the Webb must accomplish additional “unfoldings.” The craft will need to deploy a large scaffold structure to support a sunscreen that shields it from heat and light, followed by a five-layer Kapton sunscreen. The telescope, operating at temperatures below -380 Fahrenheit (-229 C), will always point away from Earth, the sun and moon.

Following those maneuvers, the spacecraft will then unfold 18 small, hexagonal mirrors that fit together down to the nanometer, together comprising the telescope’s 6.5 meters (21.5 feet) mirror. After assembly and arrival at L2, the Webb will have six months of mirror alignment, instrument calibration and other testing before it begins its mission.

If successful, the Webb’s ascent will undoubtedly cheer thousands of scientists who have watched in despair as multiple miscues, soaring costs and slipped deadlines bedeviled the project, which Congress nearly scuttled 10 years ago due to the steep budget overruns. The main contractor is Northrop Grumman Corp.

The Webb is likely to have its earliest “wins” in the area of exoplanet observations, planets that orbit stars in galaxies far from our own, said Alex Ji, a near-field cosmologist and assistant professor at the University of Chicago.

“I think this is going to have an impact on the same level as Hubble,” Ji said, noting the iconic images that telescope collected, capturing the public’s imagination. “What speaks to the power of this telescope across the entire span of astrophysics is how many people are excited about it.”

©2021 Bloomberg L.P.

Adblock test (Why?)

Source link

Continue Reading


Massive Iceberg Released Over 150 Billion Tons of Fresh Water Into Ocean As It Scraped Past South Georgia – SciTechDaily



The A68A iceberg with some smaller parts of ice that have broken off around it (November 21, 2020). Credit: MODIS image from NASA Worldview Snapshots

Scientists monitoring the giant A68A Antarctic iceberg from space reveal that a huge amount of fresh water was released as it melted around the sub-Antarctic island of South Georgia.

152 billion tonnes of fresh water – equivalent to 20 x Loch Ness or 61 million Olympic sized swimming pools, entered the seas around the sub-Antarctic island of South Georgia when the megaberg A68A melted over 3 months in 2020/2021, according to a new study. 

In July 2017, the A68A iceberg snapped off the Larsen-C Ice Shelf on the Antarctic Peninsula and began its epic 3.5 year, 4000 km journey across the Southern Ocean. At 5719 square kilometers in extent – quarter the size of Wales –, it was the biggest iceberg on Earth when it formed and the sixth largest on record. Around Christmas 2020, the berg received widespread attention as it drifted worryingly close to South Georgia, raising concerns it could harm the island’s fragile ecosystem.

Researchers from the Centre for Polar Observation and Modelling (CPOM) and British Antarctic Survey (BAS) used satellite measurements to chart the A68A iceberg’s area and thickness change throughout its life cycle. The authors show that the berg had melted enough as it drifted to avoid damaging the sea floor around South Georgia by running aground. However, a side effect of the melting was the release of a colossal 152 billion tonnes of fresh water in close proximity to the island – a disturbance that could have a profound impact on the island’s marine habitat.

A68A Iceberg Approaching the Island of South Georgia

A68A iceberg approaching the island of South Georgia (December 14, 2020). The left-hand part of the image are clouds. Credit: MODIS image from NASA Worldview Snapshots

For the first two years of its life, A68A stayed close to Antarctica in the cold waters of the Weddell Sea and experienced little in the way of melting.  However, once it began its northwards journey across Drake Passage it traveled through increasingly warm waters and began to melt.  Altogether, the iceberg thinned by 67 meters from its initial 235 m thickness, with the rate of melting rising sharply as the berg drifted in the Scotia Sea around South Georgia.

Laura Gerrish, GIS and mapping specialist at BAS and co-author of the study said:

“A68 was an absolutely fascinating iceberg to track all the way from its creation to its end. Frequent measurements allowed us to follow every move and break-up of the berg as it moved slowly northwards through iceberg alley and into the Scotia Sea where it then gained speed and approached the island of South Georgia very closely.”

[embedded content]
Thinning and breakage of the A68A iceberg over time. Melt rates increase sharply once the iceberg is drifting in open ocean north of the Antarctic peninsula. Iceberg thickness was derived from satellite altimetry data from Cryosat-2 and ICESat-2. Iceberg shape and size were sourced from Sentinel-1, Sentinel-3 and MODIS satellite data. Credit: Anne Braakmann-Folgmann CPOM

If an iceberg’s keel is too deep it can get stuck on the sea floor. This can be disruptive in several different ways; the scour marks can destroy fauna, and the berg itself can block ocean currents and predator foraging routes. All of these potential outcomes were feared when A68A approached South Georgia. However, this new study reveals that it collided only briefly with the sea floor and broke apart shortly afterward, making it less of a risk in terms of blockage.  By the time it reached the shallow waters around South Georgia, the iceberg’s keel had reduced to 141 meters below the ocean surface, shallow enough to avoid the seabed which is around 150 meters deep.

Nevertheless, the ecosystem and wildlife around South Georgia will certainly have felt the impact of the colossal iceberg’s visit.  When icebergs detach from ice shelves, they drift with the ocean currents and wind while releasing cold fresh meltwater and nutrients as they melt. This process influences the local ocean circulation and fosters biological production around the iceberg. At its peak, the iceberg was melting at a rate of 7 meters per month, and in total it released a staggering 152 billion tonnes of fresh water and nutrients.

[embedded content]

Anne Braakmann-Folgmann, a researcher at CPOM and PhD candidate at the University of Leeds’ School of Earth and Environment, is lead author of the study. She said:

“This is a huge amount of melt water, and the next thing we want to learn is whether it had a positive or negative impact on the ecosystem around South Georgia.

“Because A68A took a common route across the Drake Passage, we hope to learn more about icebergs taking a similar trajectory, and how they influence the polar oceans.”

The journey of A68A has been charted using observations from 5 different satellites. The iceberg’s area change was recorded using a combination of Sentinel-1, Sentinel-3, and MODIS imagery.  Meanwhile, the iceberg’s thickness change was measured using CryoSat-2 and ICESat-2 altimetry. By combining these measurements, the iceberg’s area, thickness, and volume change were determined.

Tommaso Parrinello, CryoSat Mission Manager at the European Space Agency, said:

“Our ability to study every move of the iceberg in such detail is thanks to advances in satellite techniques and the use of a variety of measurements. Imaging satellites record the location and shape of the iceberg and data from altimetry missions add a third dimension as they measure the height of surfaces underneath the satellites and can therefore observe how an iceberg melts.”

Reference: “Observing the disintegration of the A68A iceberg from space” by A. Braakmann-Folgmann, A. Shepherd, L. Gerrish, J. Izzard and A. Ridout, 10 January 2022, Remote Sensing of Environment.
DOI: 10.1016/j.rse.2021.112855

Adblock test (Why?)

Source link

Continue Reading


Shattered 'alphabet soup' iceberg flushed a lot of fresh water into the ocean –



A rogue iceberg that drifted dangerously close to an Antarctic penguin population in 2020 and 2021 released billions of tons of fresh water into the ocean during its breakup.

A new study, based on satellite data, tracks the aftermath of the once-mighty iceberg A-68a, which held the title of world’s largest iceberg for more than three years before shattering into a dozen pieces. (NASA’s Earth Observatory once dubbed the various mini-bergs “alphabet soup.”)

For a while, there were worries the iceberg might threaten a penguin-filled island called South Georgia, located about 940 miles (1,500 kilometers) northeast of the Antarctic Peninsula. Happily, that never came to pass, but the new research shows that the iceberg flooded the region with fresh water, potentially affecting the local ecosystem and providing yet another example of the effects of global warming on the oceans.

Related: Watch this giant iceberg break off from Antarctica

The research consulted data gathered by missions including Sentinel-1 (operated by European Space Agency, or ESA), Sentinel-3 (ESA), CryoSat-2 (ESA) and ICESat-2 (NASA), as well as the Moderate Resolution Imaging Spectroradiometer, or MODIS, instrument that flies aboard two NASA satellites, Aqua and Terra.

The satellite data shows that during the iceberg’s three-month melting period in late 2020 and early 2021, the former A-68a flushed into the ocean about 162 billion tons (152 billion metric tonnes) of fresh water — equivalent to 61 million Olympic-sized swimming pools, according to a press release from United Kingdom study participant University of Leeds.

“The berg had melted enough as it drifted to avoid damaging the sea floor around South Georgia by running aground,” the university stated. “However, a side effect of the melting was the release of a colossal 152 billion tonnes of fresh water in close proximity to the island — a disturbance that could have a profound impact on the island’s marine habitat.”

Fresh meltwater and nutrients tend to flow from melting icebergs. The freshwater flooding alters ocean circulation and the ocean ecosystem nearby the glacier fragment, the university noted.

Related stories:

“The next thing we want to learn is whether it had a positive or negative impact on the ecosystem around South Georgia,” Leeds lead author and Ph.D. candidate Anne Braakmann-Folgmann said in the same statement. 

She noted the iceberg moved across a common ocean “highway” known as the Drake Passage, so the fate of A68-A may help understand how icebergs in that zone influence the ocean in general.

A study based on the research was published in the forthcoming March 1 issue of Remote Sensing of Environment.

Follow Elizabeth Howell on Twitter @howellspace. Follow us on Twitter @Spacedotcom and on Facebook

Adblock test (Why?)

Source link

Continue Reading


Robot dog that can hike peaks in the Swiss Alps unaided could be used on other planets – Euronews



This robot dog hiked over a steep mountain in Switzerland – and it didn’t need the help of its humans to overcome the many obstacles of the rough terrain.

The skilled dog bot could be used to reach areas that are too dangerous or inaccessible to humans, including other planets, according to its creators.

The research by ETH Zurich effectively allows ANYmal, a four-legged robot dog, to move quickly over rough terrain while still taking care – a new trait for robots.

The robot dog is able to work out how to walk over any terrain by combining what its sensors can “see” with what it knows about its surroundings, just like people or animals.

“Until now when a robot used perception mostly they were just assuming that the map is always correct,” said Takahiro Miki, a PhD student at the Robotics Systems Lab at ETH Zurich.

“But often when we go outdoors this doesn’t happen, like when you go into the tall grass”.

The team used landscapes with visual obstacles like deep snow and tall grass as an example of when a robot’s camera systems produce a map of the landscape that doesn’t work when the robot puts its foot down.

ANYmal’s control system allows it to prioritise its sense of touch over its visual perception.

The team put the ability to the test on a hiking route up Mount Etzel in the Swiss Alps which stands 1,098 metres above sea level.

“The slope was quite steep, like it was even hard sometimes for us. It was quite exhausting but the robot could go over all of these obstacles and we didn’t need to help the robot,” Miki said.

The scientists hope the new skill could allow ANYmal to be deployed anywhere on Earth and on space missions to other planets.

Hundreds of four-legged robots, many of them made by Hyundai-owned Boston Dynamics, are already in use, some in hostile industrial environments, including one performing survey work in Chernobyl and another working on a BP oil rig in the Gulf of Mexico.

For more on this story, watch the video in the media player above.

Adblock test (Why?)

Source link

Continue Reading