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By NASA
1 min read
Preparations for Next Moonwalk Simulations Underway (and Underwater)
NASA is exploring potential partnerships for alternate use cases for the On-orbit Servicing, Assembly, and Manufacturing 1 (OSAM-1) flight hardware, test facilities, and experienced personnel. Through a Request for Information for OSAM-1 Partnerships released Sept. 5, 2024, NASA seeks interest from U.S. organizations that will benefit commercial, civil, and national objectives, thereby advancing domestic leadership in In-space Servicing, Assembly, and Manufacturing (ISAM) capabilities.
A comprehensive list of OSAM-1 resources and technologies organizations can consider using are outlined in the full Request for Information for OSAM-1 Partnerships available at www.sam.gov. Responses are due Sept. 30, 2024, by 11:59 p.m. EDT.
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By NASA
5 min read
NASA, ESA Missions Help Scientists Uncover How Solar Wind Gets Energy
Since the 1960s, astronomers have wondered how the Sun’s supersonic “solar wind,” a stream of energetic particles that flows out into the solar system, continues to receive energy once it leaves the Sun. Now, thanks to a lucky lineup of a NASA and an ESA (European Space Agency)/NASA spacecraft both currently studying the Sun, they may have discovered the answer — knowledge that is a crucial piece of the puzzle to help scientists better forecast solar activity between the Sun and Earth.
A paper published in the Aug. 30, 2024, issue of the journal Science provides persuasive evidence that the fastest solar winds are powered by magnetic “switchbacks,” or large kinks in the magnetic field, near the Sun.
“Our study addresses a huge open question about how the solar wind is energized and helps us understand how the Sun affects its environment and, ultimately, the Earth,” said Yeimy Rivera, co-leader of the study and a postdoctoral fellow at the Smithsonian Astrophysical Observatory, part of Center for Astrophysics | Harvard & Smithsonian. “If this process happens in our local star, it’s highly likely that this powers winds from other stars across the Milky Way galaxy and beyond and could have implications for the habitability of exoplanets.”
This artist’s concept shows switchbacks, or large kinks in the Sun’s magnetic field. NASA’s Goddard Space Flight Center/Conceptual Image Lab/Adriana Manrique Gutierrez Previously, NASA’s Parker Solar Probe found that these switchbacks were common throughout the solar wind. Parker, which became the first craft to enter the Sun’s magnetic atmosphere in 2021, allowed scientists to determine that switchbacks become more distinct and more powerful close to the Sun. Up to now, however, scientists lacked experimental evidence that this interesting phenomenon actually deposits enough energy to be important in the solar wind.
“About three years ago, I was giving a talk about how fascinating these waves are,” said co-author Mike Stevens, astrophysicist at the Center for Astrophysics. “At the end, an astronomy professor stood up and said, ‘that’s neat, but do they actually matter?’”
To answer this, the team of scientists had to use two different spacecraft. Parker is built to fly through the Sun’s atmosphere, or “corona.” ESA’s and NASA’s Solar Orbiter mission is also on an orbit that takes it relatively close to the Sun, and it measures solar wind at larger distances.
The discovery was made possible because of a coincidental alignment in February 2022 that allowed both Parker Solar Probe and Solar Orbiter to measure the same solar wind stream within two days of each other. Solar Orbiter was almost halfway to the Sun while Parker was skirting the edge of the Sun’s magnetic atmosphere.
This conceptual image shows Parker Solar Probe about to enter the solar corona. NASA/Johns Hopkins APL/Ben Smith An artist’s concept shows Solar Orbiter near the Sun. NASA’s Goddard Space Flight Center Conceptual Image Lab
“We didn’t initially realize that Parker and Solar Orbiter were measuring the same thing at all. Parker saw this slower plasma near the Sun that was full of switchback waves, and then Solar Orbiter recorded a fast stream which had received heat and with very little wave activity,” said Samuel Badman, astrophysicist at the Center for Astrophysics and the other co-lead of the study. “When we connected the two, that was a real eureka moment.”
Scientists have long known that energy is moved throughout the Sun‘s corona and the solar wind, at least in part, through what are known as “Alfvén waves.” These waves transport energy through a plasma, the superheated state of matter that makes up the solar wind.
However, how much the Alfvén waves evolve and interact with the solar wind between the Sun and Earth couldn’t be measured — until these two missions were sent closer to the Sun than ever before, at the same time. Now, scientists can directly determine how much energy is stored in the magnetic and velocity fluctuations of these waves near the corona, and how much less energy is carried by the waves farther from the Sun.
The new research shows that the Alfvén waves in the form of switchbacks provide enough energy to account for the heating and acceleration documented in the faster stream of the solar wind as it flows away from the Sun.
“It took over half a century to confirm that Alfvenic wave acceleration and heating are important processes, and they happen in approximately the way we think they do,” said John Belcher, emeritus professor from the Massachusetts Institute of Technology who co-discovered Alfvén waves in the solar wind but was not involved in this study.
In addition to helping scientists better forecast solar activity and space weather, such information helps us understand mysteries of the universe elsewhere and how Sun-like stars and stellar winds operate everywhere.
“This discovery is one of the key puzzle pieces to answer the 50-year-old question of how the solar wind is accelerated and heated in the innermost portions of the heliosphere, bringing us closer to closure to one of the main science objectives of the Parker Solar Probe mission,” said Adam Szabo, Parker Solar Probe mission science lead at NASA.
By Megan Watzke
Center for Astrophysics | Harvard & Smithsonian
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Last Updated Aug 30, 2024 Related Terms
Goddard Space Flight Center Heliophysics Heliophysics Division Parker Solar Probe (PSP) Science & Research Science Mission Directorate Solar Flares Solar Orbiter Solar Science Solar Wind Space Weather The Sun The Sun & Solar Physics Explore More
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By NASA
5 Min Read Webb Finds Early Galaxies Weren’t Too Big for Their Britches After All
This image shows a small portion of the field observed by NASA’s James Webb Space Telescope’s NIRCam (Near-Infrared Camera) for the Cosmic Evolution Early Release Science (CEERS) survey. The full image appears below. Credits:
NASA, ESA, CSA, S. Finkelstein (University of Texas) It got called the crisis in cosmology. But now astronomers can explain some surprising recent discoveries.
When astronomers got their first glimpses of galaxies in the early universe from NASA’s James Webb Space Telescope, they were expecting to find galactic pipsqueaks, but instead they found what appeared to be a bevy of Olympic bodybuilders. Some galaxies appeared to have grown so massive, so quickly, that simulations couldn’t account for them. Some researchers suggested this meant that something might be wrong with the theory that explains what the universe is made of and how it has evolved since the big bang, known as the standard model of cosmology.
According to a new study in the Astrophysical Journal led by University of Texas at Austin graduate student Katherine Chworowsky, some of those early galaxies are in fact much less massive than they first appeared. Black holes in some of these galaxies make them appear much brighter and bigger than they really are.
“We are still seeing more galaxies than predicted, although none of them are so massive that they ‘break’ the universe,” Chworowsky said.
The evidence was provided by Webb’s Cosmic Evolution Early Release Science (CEERS) Survey, led by Steven Finkelstein, a professor of astronomy at UT Austin and study co-author.
Image A : CEERS Deep Field (NIRCam)
This image shows a small portion of the field observed by NASA’s James Webb Space Telescope’s NIRCam (Near-Infrared Camera) for the Cosmic Evolution Early Release Science (CEERS) survey. It is filled with galaxies. Some galaxies appear to have grown so massive, so quickly, that simulations couldn’t account for them. However, a new study finds that some of those early galaxies are in fact much less massive than they first appeared. Black holes in some of those galaxies make them appear much brighter and bigger than they really are. NASA, ESA, CSA, S. Finkelstein (University of Texas)
View 8k pixel full resolution version of the image
Black Holes Add to Brightness
According to this latest study, the galaxies that appeared overly massive likely host black holes rapidly consuming gas. Friction in the fast-moving gas emits heat and light, making these galaxies much brighter than they would be if that light emanated just from stars. This extra light can make it appear that the galaxies contain many more stars, and hence are more massive, than we would otherwise estimate. When scientists remove these galaxies, dubbed “little red dots” (based on their red color and small size), from the analysis, the remaining early galaxies are not too massive to fit within predictions of the standard model.
“So, the bottom line is there is no crisis in terms of the standard model of cosmology,” Finkelstein said. “Any time you have a theory that has stood the test of time for so long, you have to have overwhelming evidence to really throw it out. And that’s simply not the case.”
Efficient Star Factories
Although they’ve settled the main dilemma, a less thorny problem remains: There are still roughly twice as many massive galaxies in Webb’s data of the early universe than expected from the standard model. One possible reason might be that stars formed more quickly in the early universe than they do today.
“Maybe in the early universe, galaxies were better at turning gas into stars,” Chworowsky said.
Star formation happens when hot gas cools enough to succumb to gravity and condense into one or more stars. But as the gas contracts, it heats up, generating outward pressure. In our region of the universe, the balance of these opposing forces tends to make the star formation process very slow. But perhaps, according to some theories, because the early universe was denser than today, it was harder to blow gas out during star formation, allowing the process to go faster.
More Evidence of Black Holes
Concurrently, astronomers have been analyzing the spectra of “little red dots” discovered with Webb, with researchers in both the CEERS team and others finding evidence of fast-moving hydrogen gas, a signature of black hole accretion disks. This supports the idea that at least some of the light coming from these compact, red objects comes from gas swirling around black holes, rather than stars – reinforcing Chworowsky and their team’s conclusion that they are probably not as massive as astronomers initially thought. However, further observations of these intriguing objects are incoming, and should help solve the puzzle about how much light comes from stars versus gas around black holes.
Often in science, when you answer one question, that leads to new questions. While Chworowsky and their colleagues have shown that the standard model of cosmology likely isn’t broken, their work points to the need for new ideas in star formation.
“And so there is still that sense of intrigue,” Chworowsky said. “Not everything is fully understood. That’s what makes doing this kind of science fun, because it’d be a terribly boring field if one paper figured everything out, or there were no more questions to answer.”The James Webb Space Telescope is the world’s premier space science observatory. Webb is solving mysteries in our solar system, looking beyond to distant worlds around other stars, and probing the mysterious structures and origins of our universe and our place in it. Webb is an international program led by NASA with its partners, ESA (European Space Agency) and CSA (Canadian Space Agency).
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Media Contacts
Laura Betz – laura.e.betz@nasa.gov, Rob Gutro – rob.gutro@nasa.gov
NASA’s Goddard Space Flight Center, Greenbelt, Md.
Marc Airhart – mairhart@austin.utexas.edu
University of Texas at Austin
Christine Pulliam – cpulliam@stsci.edu
Space Telescope Science Institute, Baltimore, Md.
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Last Updated Aug 26, 2024 Editor Stephen Sabia Contact Laura Betz laura.e.betz@nasa.gov Related Terms
Astrophysics Galaxies Galaxies, Stars, & Black Holes Galaxies, Stars, & Black Holes Research Goddard Space Flight Center James Webb Space Telescope (JWST) Science & Research The Universe View the full article
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