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Hottest April on record is the 11th record-breaking month in a row
Hottest April on record is the 11th record-breaking month in a row
Longest-living cat breeds revealed by life expectancy study
Longest-living cat breeds revealed by life expectancy study
A Nebula that Extends its Hand into Space
The Gum Nebula is an emission nebula almost 1400 light-years away. It’s home to an object known as “God’s Hand” among the faithful. The rest of us call it CG 4.
Many objects in space take on fascinating, ethereal shapes straight out of someone’s psychedelic fantasy. CG4 is definitely ethereal and extraordinary, but it’s also a little more prosaic. It looks like a hand extending into space.
The Dark Energy Camera (DECam) on the NSF’s Víctor M. Blanco 4-meter Telescope captured the image. DECam’s primary job is to survey hundreds of millions of galaxies in its study of dark energy. But it’s also a general-purpose instrument used for other scientific endeavours.
CG 4 is called a cometary globule because of its appearance. But it’s actually a star-forming region. It has a head that’s about 1.5 light-years in diameter and a tail that’s about 8 light-years long. The head is dense and opaque and is lit up by a nearby star. The globule is surrounded by a diffuse red glow, emissions from ionized hydrogen.
This excerpt shows a close-up of CG 4. The hand looks like it’s about to grasp an edge-on spiral galaxy named ESO 257-19 (PGC 21338). But the galaxy is more than a hundred million light-years beyond CG 4. Only a chance alignment makes it seem close. Near the head of the cometary globule are two young stellar objects (YSOs). They’re stars in their early stage of evolution before they become main-sequence stars. Image Credits: Credit: CTIO/NOIRLab/DOE/NSF/AURAImage Processing: T.A. Rector (University of Alaska Anchorage/NSF’s NOIRLab), D. de Martin & M. Zamani (NSF’s NOIRLab)
There are lots of cometary globules in the Milky Way. They’re a sub-class of objects called Bok globules, after astronomer Bart Bok, who discovered them. Both types of globules are dark nebulae, molecular clouds so dense they block optical light. Astronomers aren’t absolutely certain how cometary globules get their shape.
But they do know what’s happening to them.
The red glow surrounding CG 4 is ionized hydrogen lit up by radiation from nearby hot, massive stars. That same radiation is eroding CG 4 away. Since the globule is denser than its surroundings, it’s resisting diffusion. It still contains enough gas and dust to form several new stars about as massive as the Sun.
In this zoom-in, the hand looks more like the mouth of the Shai-Hulud, reaching out into space to destroy the approaching Sardaukar. Image Credit: CTIO/NOIRLab/DOE/NSF/AURA. Image Processing: T.A. Rector (University of Alaska Anchorage/NSF’s NOIRLab), D. de Martin & M. Zamani (NSF’s NOIRLab)Even though there are many of these globules in the Milky Way, the majority of them are in the Gum Nebula. Scientists know of 31 other globules in the nebula. This one’s called CG 4 (Cometary Globule 4) because they’re all numbered.
This image shows three of the 32 CGs in the Gum Nebula: CG 30, 31, and 8. Image Credit: By Legacy Surveys / D.Lang (Perimeter Institute) & Meli Thev – Own work, CC BY 4.0, https://commons.wikimedia.org/w/index.php?curid=143429111The Gum Nebula is likely the remnant of a huge supernova explosion, and that could be the reason the globules have their unique shape. They may have originally been spherical nebula like the Ring Nebula. But a powerful supernova explosion about one million years ago stretched them into their long, comet-like forms.
The James Webb Space Telescope captured this image of the Southern Ring Nebula, or NGC 3132, with its NIRCAM instrument. Cometary globules could’ve started out as ring-shaped nebulae before being deformed by supernova explosions. Image Credit: By Image: NASA/ESA/CSA/Space Telescope Science Institute. Public DomainAstronomers also suggest another reason for their shape. Nearby hot, massive stars exert radiation pressure on the globules, and their stellar wind also slams into them. In the Gum Nebula, their tails point away from the Vela Supernova Remnant and the pulsar that sits in its centre. Since the Vela Pulsar is a spinning neutron star, it’s possible that its winds and radiation pressure are shaping CG 4.
Whatever its cause, the Hand of God is a visually intriguing object. If you really want to lose yourself in this amazing nebula, download the TIFF file here.
The post A Nebula that Extends its Hand into Space appeared first on Universe Today.
Renewables supply 30 per cent of global electricity for the first time
Renewables supply 30 per cent of global electricity for the first time
International SWOT Mission Can Improve Flood Prediction
Rivers, lakes, and reservoirs are like our planet’s arteries, carrying life-sustaining water in interconnected networks. When Earth’s water cycle runs too fast, flooding can result, threatening lives and property. That risk is increasing as climate change alters precipitation patterns and more people are living in flood-prone areas worldwide.
Scientists and water managers use many types of data to predict flooding. This year they have a new tool at their disposal: freshwater data from the Surface Water and Ocean Topography (SWOT) satellite. The observatory, a collaboration between NASA and the French space agency, CNES (Centre National d’Études Spatiales), is measuring the height of nearly all water surfaces on Earth. SWOT was designed to measure every major river wider than about 300 feet (100 meters), and preliminary results suggest it may be able to observe much smaller rivers.
Flooding from monsoon rains covers a wide region of northeast Bangladesh in this Oct. 8, 2023, image showing data from SWOT. The U.S.-French satellite is the first to provide timely, precise water surface elevation information over entire regions at high resolution, enabling improved flooding forecasts.
Stream gauges can accurately measure water levels in rivers, but only at individual locations, often spaced far apart. Many rivers have no stream gauges at all, particularly in countries without resources to maintain and monitor them. Gauges can also be disabled by floods and are unreliable when water overtops the riverbank and flows into areas they cannot measure.
SWOT provides a more comprehensive, 3D look at floods, measuring their height, width, and slope. Scientists can use this data to better track how floodwaters pulse across a landscape, improving predictions of where flooding will occur and how often.
SWOT river slope data — like that depicted here for California’s Sacramento River — can improve predictions of how fast water flows through rivers and off landscapes. To calculate slope, scientists subtract the lower water elevation (right) from the higher one (left) and divide by segment length. Building a Better Flood Model
One effort to incorporate SWOT data into flood models is led by J. Toby Minear of the Cooperative Institute for Research in Environmental Sciences (CIRES) in Boulder, Colorado. Minear is investigating how to incorporate SWOT data into the National Oceanic and Atmospheric Administration’s National Water Model, which predicts the potential for flooding and its timing along U.S. rivers. SWOT freshwater data will fill in spatial gaps between gauges and help scientists like Minear determine the water levels (heights) at which flooding occurs at specific locations along rivers.
UNC-Chapel Hill doctoral student Marissa Hughes levels a tripod to install a GPS unit to precisely measure the water surface elevation of a segment of New Zealand’s Waimakariri River. The measurements were used to calibrate and validate data from the U.S.-French SWOT satellite
He expects SWOT to improve National Water Model data in multiple ways. For example, it will provide more accurate estimates of river slopes and how they change with streamflow. Generally speaking, the steeper a river’s slope, the faster its water flows. Hydrologic modelers use slope data to predict the speed water moves through a river and off a landscape.
SWOT will also help scientists and water managers quantify how much water lakes and reservoirs can store. While there are about 90,000 relatively large U.S. reservoirs, only a few thousand of them have water-level data that’s incorporated into the National Water Model. This limits scientists’ ability to know how reservoir levels relate to surrounding land elevations and potential flooding. SWOT is measuring tens of thousands of U.S. reservoirs, along with nearly all natural U.S. lakes larger than about two football fields combined.
Some countries, including the U.S., have made significant investments in river gauging networks and detailed local flood models. But in Africa, South Asia, parts of South America, and the Arctic, there’s little data for lakes and rivers. In such places, flood risk assessments often rely on rough estimates. Part of SWOT’s potential is that it will allow hydrologists to fill these gaps, providing information on where water is stored on landscapes and how much is flowing through rivers.
Tamlin Pavelsky, NASA’s SWOT freshwater science lead and a researcher at the University of North Carolina at Chapel Hill, says SWOT can help address the growing threat of flooding from extreme storms fueled by climate change. “Think about Houston and Hurricane Harvey in 2017,” he said. “It’s very unlikely we would have seen 60 inches of rain from one storm without climate change. Societies will need to update engineering design standards and floodplain maps as intense precipitation events become more common.”
Pavelsky says these changes in Earth’s water cycle are altering society’s assumptions about floods and what a floodplain is. “Hundreds of millions of people worldwide will be at increased risk of flooding in the future as rainfall events become increasingly intense and population growth occurs in flood-prone areas,” he added.
SWOT flood data will have other practical applications. For example, insurers can use models informed by SWOT data to improve flood hazard maps to better estimate an area’s potential damage and loss risks. A major reinsurance company, FM Global, is among SWOT’s 40 current early adopters — a global community of organizations working to incorporate SWOT data into their decision-making activities.
“Companies like FM Global and government agencies like the U.S. Federal Emergency Management Agency can fine tune their flood models by comparing them to SWOT data,” Pavelsky said. “Those better models will give us a more accurate picture of where and how often floods are likely to happen.”
More About the MissionLaunched on Dec. 16, 2022, from Vandenberg Space Force Base in central California, SWOT is now in its operations phase, collecting data that will be used for research and other purposes.
SWOT was jointly developed by NASA and CNES, with contributions from the Canadian Space Agency (CSA) and the UK Space Agency. NASA’s Jet Propulsion Laboratory, managed for the agency by Caltech in Pasadena, California, leads the project’s U.S. component. For the flight system payload, NASA provided the KaRIn instrument, a GPS science receiver, a laser retroreflector, a two-beam microwave radiometer, and NASA instrument operations. CNES provided the Doppler Orbitography and Radioposition Integrated by Satellite (DORIS) system, dual frequency Poseidon altimeter (developed by Thales Alenia Space), KaRIn radio-frequency subsystem (together with Thales Alenia Space and with support from the UK Space Agency), the satellite platform, and ground operations. CSA provided the KaRIn high-power transmitter assembly. NASA provided the launch vehicle and the agency’s Launch Services Program, based at Kennedy Space Center, and managed the associated launch services.
For more on SWOT, visit:
News Media ContactJane J. Lee / Andrew Wang
Jet Propulsion Laboratory, Pasadena, Calif.
818-354-0307 / 626-379-6874
jane.j.lee@jpl.nasa.gov / andrew.wang@jpl.nasa.gov
Written by Alan Buis
2024-060
20 Years Ago: NASA Selects its 19th Group of Astronauts
On May 6, 2004, NASA announced the selection of its 19th group of astronauts. The group comprised 11 candidates – two pilots, six mission specialists, and three educator mission specialists – and included two women, two Hispanic Americans, and one African American. Three astronauts from the Japan Aerospace Exploration Agency (JAXA) joined the 11 NASA astronauts for the 20-month training program to qualify as mission specialists, following which they became eligible for flight assignments. They comprised the last group of astronauts selected to fly on the space shuttle. All members of the group completed at least one spaceflight, with five making a single trip into space, four making two trips, and five going three times. Several remain on active status and available for future flight assignments.
The Group 19 NASA and Japan Aerospace Exploration Agency astronaut candidates pose for a group photo – front row, Robert L. Satcher, left, Dorothy “Dottie” M. Metcalf-Lindenburger, Christopher J. Cassidy, Richard R. Arnold, Randolph J. Bresnik, and Thomas H. Marshburn; back row, Akihiko “Aki” Hoshide, left, Shannon Walker, Joseph M. Acaba, James P. Dutton, R. Shane Kimbrough, Satoshi Furukawa, José M. Hernández, and Naoko Yamazaki.
In a ceremony held at the Stephen F. Udvar-Hazy Center of the Smithsonian Institution’s National Air and Space Museum in Chantilly, Virginia, NASA Administrator Sean C. O’Keefe and Chief of the Astronaut Office Kent V. Rominger introduced the 11 new astronaut candidates, the first selected since the Columbia accident. John H. Glenn, representing the original Mercury 7 astronauts selected in 1959, also attended the ceremony. The newest class of astronaut candidates included Randolph J. Bresnik and James P. Dutton as the two pilot candidates; Christopher J. Cassidy, José M. Hernández, R. Shane Kimbrough, Thomas H. Marshburn, Robert “Bobby” L. Satcher, and Shannon Walker as the mission specialists; and Joseph M. Acaba, Richard R. Arnold, and Dorothy “Dottie” M. Metcalf-Lindenburger as the educator astronauts. Under a joint agreement between the two agencies, JAXA astronauts Satoshi Furukawa, Akihiko “Aki” Hoshide, and Naoko Yamazaki, selected in 1999, joined the 11 NASA astronauts for the 20-month certification program.
Group 19 astronaut candidates during survival training at Brunswick Naval Air Station in Maine.
The 11 NASA and three JAXA astronaut candidates began their 18-month training and certification period in June 2004. The training included scientific and technical briefings, intensive instruction in shuttle and International Space Station systems, physiological training, T-38 flight training, and water and wilderness survival training. They also received orientation tours at all NASA centers. They completed the astronaut candidate training in February 2006 and qualified for various technical assignments within the astronaut office and for future flight assignments.
Group 19 patch, left, and NASA astronauts Joseph M. Acaba and Richard R. Arnold.
Per tradition, the previous astronaut class provided the nickname for Group 19: The Peacocks. The Group 19 astronauts designed their patch, that included elements such as the American and Japanese flags, a stylized astronaut pin, fourteen stars representing the astronauts, a book – representing knowledge and learning – with a Roman numeral XIX on it, and the Earth, Moon, and Mars, representing current and future exploration. The border of the patch contained the Latin words Explorandi Concitandi Docendi Gratia, meaning “for the sake of exploring, inspiring, and teaching.”
Acaba, one of the three educator astronauts, hails from California. He received his first spaceflight assignment as a mission specialist on STS-119, the 2009 mission that brought the final truss segment to the space station. He conducted two spacewalks, one of them with fellow Peacock Arnold. Acaba then traveled to the station for his second mission, this time on a Russian Soyuz spacecraft, to serve as a flight engineer during Expedition 31 and 32 in 2012, during which the crew welcomed the first commercial cargo vehicle, a SpaceX Dragon. He completed his third mission as a flight engineer during Expedition 53 and 54 in 2012 to 2013, performing a single spacewalk. Acaba spent a total of 306 days in space and 19 hours and 46 minutes outside during three spacewalks. He has served as the Chief of the Astronaut Office since 2023.
The second of the three educator astronauts, Arnold, a resident of Maryland, flew with Acaba on STS-119 in 2009. He conducted two spacewalks, one of them with fellow Peacock Acaba. His second flight took place nine years later when he served as a flight engineer during Expedition 55 and 56 and performed three more spacewalks. He has logged 209 days in space and accumulated 32 hours and 4 minutes of spacewalk time during five excursions.
Group 19 NASA astronauts Randolph J. Bresnik, left, Christopher J. Cassidy, and James P. Dutton.
Bresnik, a U.S. Marine test pilot from California, received his first spaceflight assignment as a mission specialist on STS-129, a utilization and logistics flight that brought two External Logistics Carriers to the space station. He conducted two spacewalks during the 11-day flight, including one with fellow Peacock Satcher. During his second spaceflight in 2017, Bresnik flew to the station on a Soyuz, spending 139 days in space, first as a flight engineer during Expedition 52 and then as commander of Expedition 53, and conducted three more spacewalks. He logged a total of 149 days in space, and 32 hours outside during five spacewalks. Since 2018, Bresnik has served as assistant to the chief of the astronaut office for exploration.
A native of Maine and a U.S. Navy SEAL, Cassidy completed three spaceflights during his NASA career. On his first flight in 2009, he flew as a mission specialist on STS-127, the flight that delivered the Japanese Kibo Exposed Facility to the station. He performed three spacewalks during the 16-day mission, two of them with fellow Peacock Marshburn. He returned to the space station in 2013 via a Soyuz and served as a flight engineer during Expeditions 35 and 36, spending 166 days in space and conducting three spacewalks including one terminated early when fellow spacewalker Luca Parmitano’s helmet began filling with water. On his third mission in 2020, Cassidy served as flight engineer during Expedition 62 and commanded Expedition 63. He conducted four more spacewalks. He spent a total of 378 days in space and 54 hours 51 minutes outside on nine spacewalks.
A native of Oregon and a colonel in the U.S. Air Force, Dutton flew as pilot on STS-131, a resupply mission to the space station in 2010. Fellow Peacocks Metcalf-Lindenburger and Yamazaki accompanied Dutton on the flight. The Multi-Purpose Logistics Module (MPLM) brought 27,000 pounds of supplies to the station, and returned 6,000 pounds of science, hardware, and trash back to the ground. Dutton logged 15 days in space.
Group 19 NASA astronauts José M. Hernández, left, R. Shane Kimbrough, and Thomas H. Marshburn.
California native Hernández joined the Materials and Processes Branch at NASA’s Johnson Space Center (JSC) in Houston prior to his selection as an astronaut. He made his one spaceflight on STS-128 in 2009, an expedition crew member rotation flight that also delivered 18,000 pounds of supplies, cargo, and science to the space station inside an MPLM. He logged 14 days in space. The 2023 motion picture “A Million Miles Away” chronicled Hernández’s journey to become an astronaut.
Texas native and U.S. Army aviator Kimbrough joined JSC in 2000 at Ellington Field’s Aircraft Operations Division before joining the astronaut corps. The first NASA astronaut from Group 19 to get a flight assignment, Kimbrough flew as a mission specialist on STS-126 in 2008. During the 16-day mission, the astronauts carried out an expedition crew member rotation and resupplied the station with 14,000 pounds of supplies including facilities to enable six-person occupancy of the station. Kimbrough completed two spacewalks during STS-126. For his second spaceflight, Kimbrough launched on a Soyuz and flew as a flight engineer on Expedition 49, becoming commander of Expedition 50 a week later. During the 173-day mission in 2016-2017, he conducted four spacewalks. For his third flight, Kimbrough served as the commander of Crew-2 and as flight engineer during Expedition 65/66 in 2021, flying with fellow Peacock Hoshide. During the 199-day mission he conducted three more spacewalks, bringing his total to nine and more than 59 hours outside the station. During his three spaceflights, he accumulated 388 days in space.
A native of North Carolina, Marshburn served as a flight surgeon at JSC before his selection as an astronaut, supporting Shuttle/Mir, space shuttle, and space station crews. On his first spaceflight, the 16-day STS-127 in 2009, he served as a mission specialist to help deliver the Japanese Kibo Exposed Facility and performed three spacewalks, two of them with fellow Peacock Cassidy. On his second spaceflight, Marshburn launched on a Soyuz and served as flight engineer on Expedition 34/35 in 2012 and 2013. During the 145-day mission, he completed one spacewalk. On his third mission, he served as Crew-3 pilot and flight engineer on the 176-day Expedition 66/67, completing one more spacewalk to bring his total to five, spending 31 hours outside the station. On his three flights, Marshburn spent 377 days in space.
Group 19 NASA astronauts Dorothy “Dottie” M. Metcalf-Lindenburger, left, Robert L. Satcher, and Shannon Walker.
The third educator astronaut, Denver native Metcalf-Lindenburger made her one spaceflight as a mission specialist on STS-131, flying with fellow Peacocks Dutton and Yamazaki. During the 15-day mission in 2010, the astronauts resupplied the station, including bringing 27,000 pounds of supplies in the MPLM and returning 6,000 pounds of hardware and science back to Earth.
A native of Virginia, Satcher worked as an orthopedic surgeon before his selection as an astronaut. He made his one spaceflight as a mission specialist on STS-129, an 11-day flight in 2009. During the utilization and logistics flight that brought two External Logistics Carriers to the station, Satcher performed two spacewalks, including one with fellow Peacock Bresnik, totaling 12 hours 19 minutes.
Walker holds the honor as the first native Houstonian selected as an astronaut. She worked for many years in flight operations at JSC prior to her selection. On her first spaceflight in 2010, Walker launched on a Soyuz and served as a flight engineer on the 163-day Expedition 24/25. For her second flight, she served as a mission specialist on Crew-1, the first operational flight of the SpaceX Crew Dragon, and as a flight engineer during Expedition 64 and commander of Expedition 65 in 2020 and 2021. Including that 167-day flight, Walker has logged 330 days in space. She currently serves as the deputy chief of the astronaut office.
Astronauts Satoshi Furukawa, left, Akihiko “Aki” Hoshide, and Naoko Yamazaki of the Japan Aerospace Exploration Agency who joined NASA’s Group 19 for training.
Born in Yokohama, Furukawa earned a medical degree and worked as a researcher in gastrointestinal surgery before JAXA selected him as an astronaut in 1999. He joined Group 19 in June 2004 to certify as a mission specialist. For his first spaceflight, Furukawa launched on a Soyuz and served as a flight engineer during Expedition 28/29, a 167-day mission in 2011. In 2023-24, he flew as a mission specialist on Crew 7 and as a flight engineer on Expedition 69/70, spending 199 days in space. Furukawa has accumulated 366 days in orbit and remains on active status.
Hoshide, born in Tokyo, joined JAXA in 1992 and seven years later the agency selected him as an astronaut. After finishing his mission specialist certification in 2006, JAXA chose him to fly on STS-124, the flight that delivered the Kibo pressurized module to the space station in 2008. Four years later, Hoshide traveled to the space station a second time to serve as a flight engineer during Expedition 32/33. He performed three spacewalks totaling 28 hours and 17 minutes. In 2021, he returned to the station as a member of Crew-2, flying with fellow Peacock Kimbrough. He served as a flight engineer during Expedition 65 and commander of Expedition 66, spending an additional 198 days in space. Hoshide accumulated 340 days in orbit and remains on active status.
An engineer born in Chiba, Yamazaki joined JAXA in 1996, three years before the agency selected her as an astronaut. She completed her mission specialist certification in 2006 and in 2010, made her one spaceflight on STS 131, flying with fellow Peacocks Dutton and Metcalf-Lindenburger. During the 15-day mission, the astronauts transferred 27,000 pounds of supplies to the station from the MPLM and returned 6,000 pounds back to Earth. Yamazaki operated both the shuttle and station remote manipulator systems during the flight. The STS-131 mission took place while fellow JAXA astronaut Soichi Noguchi served as an Expedition 23 flight engineer, marking the first time two Japanese astronauts flew in space at the same time.
Summary of spaceflights by Group 19 astronauts.
The Group 19 NASA and JAXA astronauts have made and continue to make significant contributions to the space station – assembly, research, maintenance, logistics, management – traveling to space and back using three different spacecraft – space shuttle, Soyuz, and Crew Dragon. Kimbrough, Marshburn, and Hoshide flew all three during their careers. As a group, they completed 28 flights spending 2,913 days, or nearly eight years, in space. They comprised the last group selected to fly on the space shuttle before its retirement in 2011. Eight of the 14 performed 43 spacewalks spending 275 hours and 46 minutes, or more than 11 days, outside the spacecraft. With several of the astronauts still on active duty, the story of Group 19 remains unfinished.
Explore More 14 min read 35 Years Ago: STS-30 Launches Magellan to Venus Article 6 days ago 18 min read Asian-American and Native Hawaiian Pacific Islander Heritage Month Article 7 days ago 5 min read NASA and Art Article 1 week ago41,000 Years Ago Earth’s Shield Went Down
Earth is naked without its protective barrier. The planet’s magnetic shield surrounds Earth and shelters it from the natural onslaught of cosmic rays. But sometimes, the shield weakens and wavers, allowing cosmic rays to strike the atmosphere, creating a shower of particles that scientists think could wreak havoc on the biosphere.
This has happened many times in our planet’s history, including 41,000 years ago in an event called the Laschamps excursion.
Cosmic rays are high-energy particles, usually protons or atomic nuclei, that travel through space at relativistic speeds. Normally, they’re deflected into space and away from Earth by the planet’s magnetic shield. But the shield is a natural phenomenon and its strength fluctuates, as does its orientation. When that happens, cosmic rays strike the Earth’s atmosphere.
That creates a shower of secondary particles called cosmogenic radionuclides. These isotopes become embedded in sediments and ice cores and even in the structure of living things like trees. There are different types of these isotopes, including ones like Calcium 41 and Carbon 14.
Showers of high-energy particles occur when energetic cosmic rays strike the top of the Earth’s atmosphere. Illustration Credit: Simon Swordy (U. Chicago), NASA.Some of the isotopes are stable, and some are radioactive. The radioactive ones have half-lives ranging from only 20 minutes (Carbon 11) up to 15.7 million years (Xenon 129.)
When Earth’s shield weakens, more of these isotopes reach the planet’s surface and collect in sediments and ice. By studying these cores and sediments, scientists can determine the magnetic shield’s history. Their observations show that Earth experienced a geomagnetic excursion or reversal 41,000 years ago. It’s called the Laschamps excursion after the Laschamps lava flows in France, where geomagnetic anomalies revealed its occurrence.
Every few hundred thousand years, the Earth’s magnetic poles flip. North becomes South and vice versa. In between those major events are more minor events called excursions. During excursions, the poles shift around for a while without swapping places. The excursions weaken the Earth’s shield and can last from a few thousand to tens of thousands of years. When that happens, more cosmic rays strike the atmosphere, creating more radionuclides that shower down onto Earth.
Scientists often focus on one particular radioactive isotope in paleomagnetic studies. Beryllium 10 has a relatively long half-life of 1.36 million years and tends to accumulate on the soil surface.
Sanja Panovska is a researcher at GFZ Potsdam, Germany, who studies geomagnetism. At the recent European Geosciences Union (EGU) General Assembly 2024, Panovska presented new research on the Laschamps excursion. She found that during the Laschamps excursion, production of Be 10 was twice as high as normal.
To understand the Laschamps excursion more thoroughly, Panovska combined cosmogenic radionuclide and paleomagnetic data to reconstruct the Earth’s magnetic field at the time. She found that when the field decreased in strength, it also shrank. The transition from normal field to reversed field took about 250 years, and it stayed flipped for about 440 years. During the transition, the Earth’s shield weekend to as little as 5% of its normal strength. When it was fully reversed, it was at about 25% of its regular strength. This weakening allowed more Be 10 and other cosmogenic radionuclides to reach Earth’s surface.
Each map shows the intensity of Earth’s geomagnetic field at different snapshots in time, according to Panovska’s reconstructions that are constrained by both paleomagnetic data and records of cosmogenic beryllium-10 radionuclides. DM stands for Dipole Moment, which is a measure of the field’s polarity or separation of positive and negative. Age [ka BP] is the age measures in thousands of years before the present. Image Credit: Sanja Panovska.These radionuclides do more than collect in sediments and ice. Some of them are radioactive. The weakening of the shield also weakened the ozone layer, letting more UV radiation reach Earth’s surface. The high-altitude atmosphere also cooled, which changed the wind flows. This could’ve caused drastic changes on the Earth’s surface.
For these reasons, the Laschamps event has been linked to the extinction of the Neanderthals, the extinction of Australian megafauna, and even to the appearance of cave art. Those links haven’t withstood scientific scrutiny, but that doesn’t mean that events like the Laschamps event aren’t hazardous. If it occurred now, it would knock out our power grids. The Earth’s equatorial region would light up with aurorae.
“Understanding these extreme events is important for their occurrence in the future, space climate predictions, and assessing the effects on the environment and on the Earth system,” Panovska said.
Scientists are learning that the magnetic shield isn’t static. There are anomalies. One of them is the South Atlantic Anomaly, a region where the magnetic field is weakest near Earth. When satellites pass over this region, they’re exposed to higher levels of ionizing radiation. The anomaly is likely caused by a reservoir of dense rock inside Earth, illustrating how complex the magnetic shield is.
The ‘South Atlantic Anomaly’ refers to an area where Earth’s protective magnetic shield is weak. Image Credit: By Christopher C. Finlay, Clemens Kloss, Nils Olsen, Magnus D. Hammer, Lars Tøffner-Clausen, Alexander Grayver & Alexey Kuvshinov – “The CHAOS-7 geomagnetic field model and observed changes in the South Atlantic Anomaly”, Earth, Planets and Space, Volume 72, Article number 156 (2020), https://earth-planets-space.springeropen.com/articles/10.1186/s40623-020-01252-9, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=99760567Scientists are uncertain about what effect the cosmic rays have on life when the magnetic shield is weak. It’s tempting to correlate extinctions with events like the Laschamps excursion when they line up temporally. But the poles have shifted, weakened, and reversed many times and life is still here and still thriving.
If humanity lasts long enough, we’ll go through one of these reversals. Then we’ll know.
The post 41,000 Years Ago Earth’s Shield Went Down appeared first on Universe Today.
Fall Into a Black Hole With this New NASA Simulation
No human being will ever encounter a black hole. But we can’t stop wondering what it would be like to fall into one of these massive, beguiling, physics-defying singularities.
NASA created a simulation to help us imagine what it would be like.
Jeremy Schnittman is an astrophysicist at NASA’s Goddard Space Flight Center and he created the visualizations. “People often ask about this, and simulating these difficult-to-imagine processes helps me connect the mathematics of relativity to actual consequences in the real universe,” he said. “So I simulated two different scenarios, one where a camera — a stand-in for a daring astronaut — just misses the event horizon and slingshots back out, and one where it crosses the boundary, sealing its fate.”
In one, the viewpoint plunges directly into the black hole like a free-falling astronaut, with explanatory text to guide us through what we’re seeing. The other is a 360-degree view of the black hole.
Schnittman created them with a NASA supercomputer called Discover in only five days, generating about 10 terabytes of data. The computer used only about 0.3% of its power. The same visualization would’ve taken more than a decade to create on an average laptop computer.
The black hole in the visualization is the same size as Sagittarius A star, the supermassive black hole (SMBH) at the heart of the Milky Way. It has 4.3 million solar masses and dominates the galaxy’s inner regions. Its event horizon reaches about 25 million km (16 million miles). That’s about 17% of the distance from Earth to the Sun. The event horizon is surrounded by an accretion disk, a swirling disk of superheated material drawn in by the black hole’s overpowering gravity.
Another type of black hole, the stellar-mass black hole, is much less massive. Schnittman says that if you’re going to fall into a black hole, you’d rather fall into the supermassive one.
“If you have the choice, you want to fall into a supermassive black hole,” Schnittman explained. “Stellar-mass black holes, which contain up to about 30 solar masses, possess much smaller event horizons and stronger tidal forces, which can rip apart approaching objects before they get to the horizon.”
Powerful gravity is the reason. The SMBH’s gravity is so strong that it pulls harder on the end of the object nearest it. That stretches the object and elongates it. Stephen Hawking was the first to call this ‘spaghettification,’ and the name has stuck. Presumably, you’d get a better look if you fall into an SMBH.
In the movies, the camera begins at a distance of 640 million km (400 million miles.) Since space-time is warped around a black hole, so are the images of the sky, the black hole’s disk, and the photon ring. It takes the camera three hours of real-time to fall into the event horizon, and it completes almost two 30-minute orbits as it falls. A distant observer would never see an object ever reach the black hole. From a distance, the object would freeze at the event horizon.
When a falling object reaches the event horizon, it and space-time itself reach the speed of light. After crossing the horizon, the object and the space-time around it surge toward the singularity, a point of infinite density and gravity. “Once the camera crosses the horizon, its destruction by spaghettification is just 12.8 seconds away,” Schnittman said.
In the second video, the camera never crosses the event horizon and instead escapes. But the powerful black hole still has an effect. Imagine if the camera were an astronaut, and they flew this six-hour roundtrip while a separate astronaut stayed far away from the SMBH. The astronaut would return and be 36 minutes younger than the astronaut who never approached the black hole.
“This situation can be even more extreme,” Schnittman noted. “If the black hole were rapidly rotating, like the one shown in the 2014 movie ‘Interstellar,’ she would return many years younger than her shipmates.”
The bottom line is, don’t fall into a black hole. In fact, resist your fascination and don’t even approach one.
Leave them for the physicists.
The post Fall Into a Black Hole With this New NASA Simulation appeared first on Universe Today.
Next-gen satellites will paint a clearer picture of a changing Earth
NASA’s TESS Returns to Science Operations
4 min read
NASA’s TESS Returns to Science OperationsNASA’s TESS (Transiting Exoplanet Survey Satellite) returned to science operations May 3 and is once again making observations. The satellite went into safe mode April 23 following a separate period of down time earlier that month.
The operations team determined this latest safe mode was triggered by a failure to properly unload momentum from the spacecraft’s reaction wheels, a routine activity needed to keep the satellite properly oriented when making observations. The propulsion system, which enables this momentum transfer, had not been successfully repressurized following a prior safe mode event April 8. The team has corrected this, allowing the mission to return to normal science operations. The cause of the April 8 safe mode event remains under investigation.
The TESS mission is a NASA Astrophysics Explorer operated by the Massachusetts Institute of Technology in Cambridge, Massachusetts. Launched in 2018, TESS has been scanning almost the entire sky looking for planets beyond our solar system, known as exoplanets. The TESS mission has also uncovered other cosmic phenomena, including star-shredding black holes and stellar oscillations. Read more about TESS discoveries at nasa.gov/tess.
Media contact:
Claire Andreoli
301-286-1940
claire.andreoli@nasa.gov
NASA’s Goddard Space Flight Center, Greenbelt, Md.
During a routine activity April 23, NASA’s TESS (Transiting Exoplanet Survey Satellite) entered safe mode, temporarily suspending science operations. The satellite scans the sky searching for planets beyond our solar system.
The team is working to restore the satellite to science operations while investigating the underlying cause. NASA also continues investigating the cause of a separate safe mode event that took place earlier this month, including whether the two events are connected. The spacecraft itself remains stable.
The TESS mission is a NASA Astrophysics Explorer operated by the Massachusetts Institute of Technology in Cambridge, Massachusetts. Launched in 2018, TESS recently celebrated its sixth anniversary in orbit. Visit nasa.gov/tess for updates.
Media contact:
Claire Andreoli
301-286-1940
claire.andreoli@nasa.gov
NASA’s Goddard Space Flight Center, Greenbelt, Md.
NASA’s TESS (Transiting Exoplanet Survey Satellite) has returned to work after science observations were suspended on April 8, when the spacecraft entered into safe mode. All instruments are powered on and, following the successful download of previously collected science data stored in the mission’s recorder, are now making new science observations.
Analysis of what triggered the satellite to enter safe mode is ongoing.
The TESS mission is a NASA Astrophysics Explorer operated by MIT in Cambridge, Massachusetts. Launched in 2018, TESS has been scanning almost the entire sky looking for planets beyond our solar system, known as exoplanets. The TESS mission has also uncovered other cosmic phenomena, including star-shredding black holes and stellar oscillations. Read more about TESS discoveries at nasa.gov/tess.
Media contact:
Claire Andreoli
301-286-1940
claire.andreoli@nasa.gov
NASA’s Goddard Space Flight Center, Greenbelt, Md.
NASA’s TESS (Transiting Exoplanet Survey Satellite) entered into safe mode April 8, temporarily interrupting science observations. The team is investigating the root cause of the safe mode, which occurred during scheduled engineering activities. The satellite itself remains in good health.
The team will continue investigating the issue and is in the process of returning TESS to science observations in the coming days.
The TESS mission is a NASA Astrophysics Explorer operated by MIT in Cambridge, Massachusetts. Launched in 2018, TESS has been scanning almost the entire sky looking for planets beyond our solar system, known as exoplanets. The TESS mission has also uncovered other cosmic phenomena, including star-shredding black holes and stellar oscillations. Read more about TESS discoveries at nasa.gov/tess.
Media Contact:
Claire Andreoli
(301) 286-1940
claire.andreoli@nasa.gov
NASA’s Goddard Space Flight Center, Greenbelt, Md.