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By European Space Agency
Video: 00:00:29 Solar wind is a never-ending stream of charged particles coming from the Sun. Rather than a constant breeze, this wind is rather gusty. As solar wind particles travel through space, they interact with the Sun's variable magnetic field, creating chaotic and fluctuating motion known as turbulence.
This video confirms something long suspected: the turbulent motion of solar wind begins very close to the Sun, inside the solar atmosphere known as the corona. Small disturbances affecting solar wind in the corona are carried outward and expand, generating turbulent flow further out in space.
By blocking out direct light coming from the Sun, the Metis coronagraph instrument on Solar Orbiter is able to capture the fainter visible and ultraviolet light coming from the solar corona. Its high-resolution images show the detailed structure and movement within the corona, revealing how solar wind motion already becomes turbulent at its roots.
The red-tinted ring in the video shows Metis observations made on 12 October 2022. At the time, the spacecraft was just 43.4 million km from the Sun, less than a third of the Sun–Earth distance. The video of the Sun in the centre of the video was recorded by Solar Orbiter’s Extreme Ultraviolet Imager (EUI) on the same day. (Read more about Solar Orbiter’s instruments here.)
“This new analysis provides the first-ever evidence for the onset of fully developed turbulence in the Sun’s corona. Solar Orbiter’s Metis coronagraph was able to detect it very close to the Sun, closer than any spacecraft could approach the Sun and make local measurements,” explains Daniel Müller, ESA’s Solar Orbiter Project Scientist.
Turbulence affects how solar wind is heated, how it moves through the Solar System and how it interacts with the magnetic fields of planets and moons it passes through. Understanding solar wind turbulence is crucial for predicting space weather and its effects on Earth.
‘Metis observation of the onset of fully developed turbulence in the solar corona’ by Daniele Telloni et al. was published today in Astrophysical Journal Letters.
[Video description: The Sun is shown in the centre, surrounded by a ring of data from Solar Orbiter’s Metis coronagraph. The data show changes in brightness of the solar corona, which directly relates to the density of charged particles. These changes are made visible by subtracting consecutive coronal brightness images taken two minutes apart. Red regions show no change, while white and black regions highlight positive and negative changes in brightness. This reveals how charged solar wind particles within the corona move in a chaotic, turbulent way. The video repeats three times.]
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By Space Force
Chief Master Sgt. of the Space Force John Bentivegna announces his three key initiatives and the new enlisted roadmap during the Air and Space Forces Association’s Air, Space & Cyber Conference.
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By NASA
Hubble Space Telescope Home NASA’s Hubble, MAVEN… Missions Hubble Home Overview About Hubble The History of Hubble Hubble Timeline Why Have a Telescope in Space? Hubble by the Numbers At the Museum FAQs Impact & Benefits Hubble’s Impact & Benefits Science Impacts Cultural Impact Technology Benefits Impact on Human Spaceflight Astro Community Impacts Science Hubble Science Science Themes Science Highlights Science Behind Discoveries Hubble’s Partners in Science Universe Uncovered Explore the Night Sky Observatory Hubble Observatory Hubble Design Mission Operations Missions to Hubble Hubble vs Webb Team Hubble Team Career Aspirations Hubble Astronauts News Hubble News Hubble News Archive Social Media Media Resources Multimedia Multimedia Images Videos Sonifications Podcasts E-books Lithographs Fact Sheets Glossary Posters Hubble on the NASA App More Online Activities 6 min read
NASA’s Hubble, MAVEN Help Solve the Mystery of Mars’ Escaping Water
NASA, ESA, STScI, John T. Clarke (Boston University); Processing: Joseph DePasquale (STScI) Mars was once a very wet planet as is evident in its surface geological features. Scientists know that over the last 3 billion years, at least some water went deep underground, but what happened to the rest? Now, NASA’s Hubble Space Telescope and MAVEN (Mars Atmosphere and Volatile Evolution) missions are helping unlock that mystery.
“There are only two places water can go. It can freeze into the ground, or the water molecule can break into atoms, and the atoms can escape from the top of the atmosphere into space,” explained study leader John Clarke of the Center for Space Physics at Boston University in Massachusetts. “To understand how much water there was and what happened to it, we need to understand how the atoms escape into space.”
Clarke and his team combined data from Hubble and MAVEN to measure the number and current escape rate of the hydrogen atoms escaping into space. This information allowed them to extrapolate the escape rate backwards through time to understand the history of water on the Red Planet.
Escaping Hydrogen and “Heavy Hydrogen”
Water molecules in the Martian atmosphere are broken apart by sunlight into hydrogen and oxygen atoms. Specifically, the team measured hydrogen and deuterium, which is a hydrogen atom with a neutron in its nucleus. This neutron gives deuterium twice the mass of hydrogen. Because its mass is higher, deuterium escapes into space much more slowly than regular hydrogen.
Over time, as more hydrogen was lost than deuterium, the ratio of deuterium to hydrogen built up in the atmosphere. Measuring the ratio today gives scientists a clue to how much water was present during the warm, wet period on Mars. By studying how these atoms currently escape, they can understand the processes that determined the escape rates over the last four billion years and thereby extrapolate back in time.
Although most of the study’s data comes from the MAVEN spacecraft, MAVEN is not sensitive enough to see the deuterium emission at all times of the Martian year. Unlike the Earth, Mars swings far from the Sun in its elliptical orbit during the long Martian winter, and the deuterium emissions become faint. Clarke and his team needed the Hubble data to “fill in the blanks” and complete an annual cycle for three Martian years (each of which is 687 Earth days). Hubble also provided additional data going back to 1991 – prior to MAVEN’s arrival at Mars in 2014.
The combination of data between these missions provided the first holistic view of hydrogen atoms escaping Mars into space.
These are far-ultraviolet Hubble images of Mars near its farthest point from the Sun, called aphelion, on December 31, 2017 (top), and near its closest approach to the Sun, called perihelion, on December 19, 2016 (bottom). The atmosphere is clearly brighter and more extended when Mars is close to the Sun.
Reflected sunlight from Mars at these wavelengths shows scattering by atmospheric molecules and haze, while the polar ice caps and some surface features are also visible. Hubble and MAVEN showed that Martian atmospheric conditions change very quickly. When Mars is close to the Sun, water molecules rise very rapidly through the atmosphere, breaking apart and releasing atoms at high altitudes. NASA, ESA, STScI, John T. Clarke (Boston University); Processing: Joseph DePasquale (STScI)
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A Dynamic and Turbulent Martian Atmosphere
“In recent years scientists have found that Mars has an annual cycle that is much more dynamic than people expected 10 or 15 years ago,” explained Clarke. “The whole atmosphere is very turbulent, heating up and cooling down on short timescales, even down to hours. The atmosphere expands and contracts as the brightness of the Sun at Mars varies by 40 percent over the course of a Martian year.”
The team discovered that the escape rates of hydrogen and deuterium change rapidly when Mars is close to the Sun. In the classical picture that scientists previously had, these atoms were thought to slowly diffuse upward through the atmosphere to a height where they could escape.
But that picture no longer accurately reflects the whole story, because now scientists know that atmospheric conditions change very quickly. When Mars is close to the Sun, the water molecules, which are the source of the hydrogen and deuterium, rise through the atmosphere very rapidly releasing atoms at high altitudes.
The second finding is that the changes in hydrogen and deuterium are so rapid that the atomic escape needs added energy to explain them. At the temperature of the upper atmosphere only a small fraction of the atoms have enough speed to escape the gravity of Mars. Faster (super-thermal) atoms are produced when something gives the atom a kick of extra energy. These events include collisions from solar wind protons entering the atmosphere or sunlight that drives chemical reactions in the upper atmosphere.
Mars was once a very wet planet. Scientists know that over the last 3 billion years, some of the water went underground, but what happened to the rest? Credit: NASA’s Goddard Space Flight Center; Lead Producer: Paul Morris; Mars Animations Producer: Dan Gallagher Serving as a Proxy
Studying the history of water on Mars is fundamental not only to understanding planets in our own solar system but also the evolution of Earth-size planets around other stars. Astronomers are finding more and more of these planets, but they’re difficult to study in detail. Mars, Earth and Venus all sit in or near our solar system’s habitable zone, the region around a star where liquid water could pool on a rocky planet; yet all three planets have dramatically different present-day conditions. Along with its sister planets, Mars can help scientists grasp the nature of far-flung worlds across our galaxy.
These results appear in the July 26 edition of Science Advances, published by the American Association for the Advancement of Science.
About the Missions
The Hubble Space Telescope has been operating for over three decades and continues to make ground-breaking discoveries that shape our fundamental understanding of the universe. Hubble is a project of international cooperation between NASA and ESA (European Space Agency). NASA’s Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope and mission operations. Lockheed Martin Space, based in Denver, Colorado, also supports mission operations at Goddard. The Space Telescope Science Institute (STScI) in Baltimore, Maryland, which is operated by the Association of Universities for Research in Astronomy, conducts Hubble science operations for NASA.
MAVEN’s principal investigator is based at the Laboratory for Atmospheric and Space Physics (LASP) at the University of Colorado Boulder. LASP is also responsible for managing science operations and public outreach and communications. NASA’s Goddard Space Flight Center in Greenbelt, Maryland, manages the MAVEN mission. Lockheed Martin Space built the spacecraft and is responsible for MAVEN mission operations at Goddard. NASA’s Jet Propulsion Laboratory in Southern California provides navigation and Deep Space Network support. The MAVEN team is preparing to celebrate the spacecraft’s 10th year at Mars in September 2024.
Facebook logo @NASAHubble @NASAHubble Instagram logo @NASAHubble Media Contacts:
Claire Andreoli
NASA’s Goddard Space Flight Center, Greenbelt, MD
claire.andreoli@nasa.gov
Ann Jenkins and Ray Villard
Space Telescope Science Institute, Baltimore, MD
Science Contact:
John T. Clarke
Boston University, Boston, MA
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Last Updated Sep 05, 2024 Editor Andrea Gianopoulos Location NASA Goddard Space Flight Center Related Terms
Astrophysics Astrophysics Division Goddard Space Flight Center Hubble Space Telescope Mars MAVEN (Mars Atmosphere and Volatile EvolutioN) Missions Planetary Science Planets Science Mission Directorate The Solar System Keep Exploring Discover More Topics From Hubble and Maven
Hubble Space Telescope
Since its 1990 launch, the Hubble Space Telescope has changed our fundamental understanding of the universe.
Hubble Science Highlights
MAVEN
The Mars Atmosphere and Volatile EvolutioN (MAVEN) mission is the first mission devoted to understanding the Martian upper atmosphere.
Mars
Mars is the fourth planet from the Sun, and the seventh largest. It’s the only planet we know of inhabited…
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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
The NASA Airborne Instrumentation for Real-world Video of Urban Environments (AIRVUE) sensor pod is attached to the base of a NASA helicopter at NASA’s Kennedy Space Center in Cape Canaveral, Florida in April 2024 before a flight to test the pod’s cameras and sensors. The AIRVUE pod will be used to collect data for autonomous aircraft like air taxis, drones, or other Advanced Air Mobility aircraft.NASA/Isaac Watson For self-flying aircraft to take to the skies, they need to learn about their environments to avoid hazards. NASA aeronautics researchers recently developed a camera pod with sensors to help with this challenge by advancing computer vision for autonomous aviation.
This pod is called the Airborne Instrumentation for Real-world Video of Urban Environments (AIRVUE). It was developed and built at NASA’s Armstrong Flight Research Center in Edwards, California. Researchers recently flew it on a piloted helicopter at NASA’s Kennedy Space Center in Cape Canaveral, Florida for initial testing.
The team hopes to use the pod to collect large, diverse, and accessible visual datasets of weather and other obstacles. They will then use that information to create a data cloud for manufacturers of self-flying air taxis or drones, or other similar aircraft, to access. Developers can use this data to evaluate how well their aircraft can “see” the complex world around them.
NASA researchers Elizabeth Nail (foreground) and A.J. Jaffe (background) prepare the NASA Airborne Instrumentation for Real-world Video of Urban Environments (AIRVUE) sensor pod for testing at NASA’s Kennedy Space Center in Cape Canaveral, Florida, in April 2024.NASA/Isaac Watson “Data is the fuel for machine learning,” said Nelson Brown, lead NASA researcher for the AIRVUE project. “We hope to inspire innovation by providing the computer vision community with realistic flight scenarios. Accessible datasets have been essential to advances in driver aids and self-driving cars, but so far, we haven’t seen open datasets like this in aviation.”
The computer algorithms that will enable the aircraft to sense the environment must be reliable and proven to work in many flight circumstances. NASA data promises that fidelity, making this an important resource for industry. When a company conducts data collection on their own, it’s unlikely they share it with other manufacturers. NASA’s role facilitates this accessible dataset for all companies in the Advanced Air Mobility industry, ensuring the United States stays at the forefront of innovation.
Once the design is refined, through evaluation and additional testing, the team hopes to make more pods that ride along on various types of aircraft to collect more visuals and grow the digital repository of data.
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Last Updated Aug 26, 2024 EditorDede DiniusContactTeresa Whitingteresa.whiting@nasa.govLocationArmstrong Flight Research Center Related Terms
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