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Hubble Space Telescope Home Hubble Examines a Busy… 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 2 min read
Hubble Examines a Busy Galactic Center
This NASA/ESA Hubble Space Telescope image features the active spiral galaxy IC 4709. ESA/Hubble & NASA, M. Koss, A, Barth This NASA/ESA Hubble Space Telescope image features the spiral galaxy IC 4709a located around 240 million light-years away in the southern constellation Telescopium. Hubble beautifully captures its faint halo and swirling disk filled with stars and dust bands. The compact region at its core might be the most remarkable sight. It holds an active galactic nucleus (AGN).
If IC 4709’s core just held stars, it wouldn’t be nearly as bright. Instead, it hosts a gargantuan black hole, 65 million times more massive than our Sun. A disk of gas spirals around and eventually into this black hole, crashing together and heating up as it spins. It reaches such high temperatures that it emits vast quantities of electromagnetic radiation, from infrared to visible to ultraviolet light and X-rays. A lane of dark dust, just visible at the center of the galaxy in the image above, obscures the AGN in IC 4709. The dust lane blocks any visible light emission from the nucleus itself. Hubble’s spectacular resolution, however, gives astronomers a detailed view of the interaction between the quite small AGN and its host galaxy. This is essential to understanding supermassive black holes in galaxies much more distant than IC 4709, where resolving such fine details is not possible.
This image incorporates data from two Hubble surveys of nearby AGNs originally identified by NASA’s Swift telescope. There are plans for Swift to collect new data on these galaxies. Swift houses three multiwavelength telescopes, collecting data in visible, ultraviolet, X-ray, and gamma-ray light. Its X-ray component will allow SWIFT to directly see the X-rays from IC 4709’s AGN breaking through the obscuring dust. ESA’s Euclid telescope — currently surveying the dark universe in optical and infrared light — will also image IC 4709 and other local AGNs. Their data, along with Hubble’s, provides astronomers with complementary views across the electromagnetic spectrum. Such views are key to fully research and better understand black holes and their influence on their host galaxies.
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Last Updated Sep 05, 2024 Editor Andrea Gianopoulos Location NASA Goddard Space Flight Center Related Terms
Active Galaxies Astrophysics Astrophysics Division Galaxies Goddard Space Flight Center Hubble Space Telescope Missions Spiral Galaxies Keep Exploring Discover More Topics From Hubble
Hubble Space Telescope
Since its 1990 launch, the Hubble Space Telescope has changed our fundamental understanding of the universe.
Hubble’s Galaxies
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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
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Hubble Zooms into the Rosy Tendrils of Andromeda
NASA, ESA, M. Boyer (Space Telescope Science Institute), and J. Dalcanton (University of Washington); Image Processing: Gladys Kober (NASA/Catholic University of America) Clusters of stars set the interstellar medium ablaze in the Andromeda Galaxy about 2.5 million light-years away. Also known as M31, Andromeda is the Milky Way’s closest major galaxy. It measures approximately 152,000 light-years across and, with almost the same mass as our home galaxy, is headed for a collision with the Milky Way in 2-4 billion years. In the meantime, Andromeda remains an object of study for many astronomers.
As a spiral galaxy, Andromeda’s winding arms are one of its most remarkable features. NASA’s Hubble Space Telescope zoomed in to get a close look at one of its tendrils in the northeast, revealing swathes of ionized gas. These regions — which are common in spiral and irregular galaxies — often indicate the presence of recent star formation. The combination of stellar nurseries and supernovae create a dynamic environment that excites the surrounding hydrogen gas, flourishing it into a garden of star-studded roses.
NASA, ESA, M. Boyer (Space Telescope Science Institute), and J. Dalcanton (University of Washington); Image Processing: Gladys Kober (NASA/Catholic University of America) Scientists probed Andromeda’s spiral arms using Hubble’s Advanced Camera for Surveys (ACS) and Wide Field Camera 3 (WFC3) to analyze the collection of stars buried in its cosmic bouquets. With ACS and WFC3’s wide spectral coverage, Hubble could peer through the hedges of gas and observe a valuable sample of these stars. The extent of the study spanned a vast range of stars, providing not just a clear view of Andromeda’s stellar history and diversity, but also more insight on stellar formation and evolution overall. By examining these stars in our local cosmic neighborhood, scientists can better understand those within galaxies in the distant universe.
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This inset image shows the location of Hubble’s view within the Andromeda galaxy. NASA, ESA, M. Boyer (Space Telescope Science Institute), J. Dalcanton (University of Washington), and KPNO/NOIRLab/NSF/AURA/Adam Block; Image Processing: Gladys Kober (NASA/Catholic University of America) This inset image shows the location of Hubble’s view within the Andromeda galaxy. NASA, ESA, M. Boyer (Space Telescope Science Institute), J. Dalcanton (University of Washington), and KPNO/NOIRLab/NSF/AURA/Adam Block; Image Processing: Gladys Kober (NASA/Catholic University of America) Explore More
Hubble’s Galaxies
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Last Updated Aug 30, 2024 Editor Michelle Belleville Location NASA Goddard Space Flight Center Related Terms
Astrophysics Galaxies Goddard Space Flight Center Hubble Space Telescope Stars Keep Exploring Discover More Topics From NASA
Hubble Space Telescope
Since its 1990 launch, the Hubble Space Telescope has changed our fundamental understanding of the universe.
Hubble Science
Hubble’s Galaxies
Stars
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By NASA
On Aug. 29, 1789, German-born British astronomer William Herschel observed a tiny bright dot orbiting around Saturn. His son later named the object Enceladus. Because of its distance from Earth and proximity to bright Saturn, for the next two centuries little remained known about Enceladus other than its size, orbital parameters, and that it held the honor as the most reflective body in the solar system. It took the Voyager flybys through the Saturn system in the early 1980s and especially the detailed observations between 2005 and 2015 by the Saturn orbiter Cassini to reveal Enceladus as a truly remarkable world, interacting with Saturn and its rings. Harboring a subsurface ocean of salty water, Enceladus may possibly be hospitable to some forms of life.
Left: Portrait (1785) of William Herschel by Lemuel Francis Abbott. Image credit: courtesy National Portrait Gallery, London. Middle: Drawing of Herschel’s 40-foot telescope. Right: Portrait (1867) of John Herschel by Julia Margaret Cameron. Image credit: Metropolitan Museum of Art.
Herschel’s previous astronomical accomplishments include the discovery of Uranus in 1781 and two of its moons, Oberon and Titania, in 1787. He also catalogued numerous objects he termed nebulae, but remained frustrated by the limitations of telescopes of his age. He began to build ever larger instruments, finally building the world’s largest reflecting telescope of its time. At 40 feet long, and with a 49-inch diameter primary mirror weighing a ton, it looked impressive although its optical characteristics did not advance the field as much as he had hoped. Nevertheless, Herschel used this telescope to observe Saturn and its five known moons, looking for others. On Aug. 28, 1789, he observed a bright point orbiting the planet and believed he had discovered a sixth moon. On Sept. 17, he discovered a seventh moon orbiting the ringed planet. He did not name these moons, that task fell to his son John who believed Saturn’s moons should be named after the Titans of Greek mythology. He named the first moon Enceladus and the second Mimas.
Left: Relative sizes of Earth, Earth’s Moon, and Enceladus. Right: Best Voyager 2 image of Enceladus.
For nearly two centuries, Enceladus remained not much more than a point of light orbiting Saturn, just another icy moon in the outer solar system. Astronomers estimated its diameter at around 310 miles and its orbital period around Saturn at 1.4 days, with a mean distance from the planet’s center of 148,000 miles. Enceladus has the distinction as one of the brightest objects in the solar system, reflecting almost 100 percent of the Sun’s light. Unusual telescope observations during the 20th century showed an increase in brightness on its trailing side, with no known explanation at the time. In 1966, astronomers discovered a diffuse ring around Saturn, the E-ring, and found in 1980 that its density peaked near Enceladus. The Voyager 1 spacecraft flew within 125,570 miles of Enceladus during its passage through the Saturn system on Nov. 12, 1980. Its twin Voyager 2 came within 54,000 miles on Aug. 26, 1981, during its flyby. These close encounters enabled the spacecraft to return the first detailed images of the moon, showing various terrains, including heavily cratered areas as well as smooth crater-free areas, indicating a very young surface.
Left: False color image of Enceladus from Cassini showing the tiger stripes at bottom. Middle: Limb view of Enceladus showing plumes of material emanating from its surface. Right: Cassini image of Enceladus backlit by the Sun showing the fountain-like plumes of material.
After the Cassini spacecraft entered orbit around Saturn in July 2004, our understanding of Enceladus increased tremendously, and of course raised new questions. Between 2005 and 2015, Cassini encountered Enceladus 22 times, turning its various instruments on the moon to unravel its secrets. It noted early on that the moon emitted gas and dust or ice particles and that they interacted with the E-ring. Images of the moon’s south polar region revealed cracks on the surface and other instruments detected a huge cloud of water vapor over the area. The moon likely had a liquid subsurface and some of this material reached the outside through these cracks. Scientists named the most prominent of these areas “tiger stripes” and later observations confirmed them as the source of the most prominent jets. During the most daring encounter in October 2015, Cassini came within 30 miles of the Enceladus’ surface, flying through the plume of material emanating from the moon. Analysis of the plumes revealed an organic brew of volatile gases, water vapor, ammonia, sodium salts, carbon dioxide, and carbon monoxide. These plumes replenish Saturn’s E-ring, and some of this material enters Saturn’s upper atmosphere, an interaction unique in the solar system. More recently, the James Webb Space Telescope imaged the water vapor plume emanating from Enceladus’ south pole, extending out 40 times the size of the moon itself. The confirmation of a subsurface ocean of salty water has led some scientists to postulate that Enceladus may be hospitable to some forms of life, making it a potential target for future exploration. Enceladus may yet have more surprises, even as scientists continue to pore over the data returned by Cassini.
Left: James Webb Space Telescope image of a water vapor plume emanating from Enceladus. Right: Illustration of the interaction of Enceladus and Saturn’s E-ring.
Map of Enceladus based on imagery from Cassini, turning our view of Enceladus from a small point of light into a unique world with its own topography.
Events in world history in 1789:
January 29 – Vietnamese emperor Quang Trung defeats Chinese Qing forces at Ngọc Hồi-Đống Đa in one of the greatest military victories in Vietnamese history.
March 10 – In Japan, the Menashi-Kunashir rebellion begins between the Ainu people and the Japanese.
April 7 – Selim III succeeds Abdul Hamid I as Sultan of the Ottoman Empire.
April 28 – Aboard the HMS Bounty in the Pacific Ocean, Fletcher Christian leads the mutiny against Captain William Bligh.
April 30 – Inauguration of George Washington as the first President of the United States of America.
July 14 – Citizens storm The Bastille fortress in Paris during the French Revolution.
September 15 – Birth of American writer James Fenimore Cooper in Burlington, New Jersey.
December 11 – Founding of the University of North Carolina, the oldest public university in the United States.
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Hubble Observes An Oddly Organized Satellite
NASA, ESA, and E. Skillman (University of Minnesota – Twin Cities; Processing: Gladys Kober (NASA/Catholic University of America) Andromeda III is one of at least 13 dwarf satellite galaxies in orbit around the Andromeda galaxy, or Messier 31, the Milky Way’s closest grand spiral galactic neighbor. Andromeda III is a faint, spheroidal collection of old, reddish stars that appears devoid of new star formation and younger stars. In fact, Andromeda III seems to be only about 3 billion years younger than the majority of globular clusters ― dense knots of stars thought to have been mostly born at the same time, which contain some of the oldest stars known in the universe.
Astronomers suspect that dwarf spheroidal galaxies may be leftovers of the kind of cosmic objects that were shredded and melded by gravitational interactions to build the halos of large galaxies. Curiously, studies have found that several of the Andromeda Galaxy’s dwarf galaxies, including Andromeda III, orbit in a flat plane around the galaxy, like the planets in our solar system orbit around the Sun. The alignment is puzzling because models of galaxy formation don’t show dwarf galaxies falling into such orderly formations, but rather moving around the galaxy randomly in all directions. As they slowly lose energy, the dwarf galaxies merge into the larger galaxy.
The odd alignment could be because many of Andromeda’s dwarf galaxies fell into orbit around it as a single group, or because the dwarf galaxies are scraps left over from the merger of two larger galaxies. Either of these theories, which are being researched via NASA’s James Webb Space Telescope, would complicate theories of galaxy formation but also help guide and refine future models.
NASA’s Hubble Space Telescope took this image of Andromeda III as part of an investigation into the star formation and chemical enrichment histories of a sample of M31 dwarf spheroidal galaxies that compared their first episodes of star formation to those of Milky Way satellite galaxies.
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Hubble’s Galaxies
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Claire Andreoli
NASA’s Goddard Space Flight Center, Greenbelt, MD
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Last Updated Aug 29, 2024 Editor Michelle Belleville Location NASA Goddard Space Flight Center Related Terms
Astrophysics Galaxies Goddard Space Flight Center Hubble Space Telescope Stars Keep Exploring Discover More Topics From NASA
Hubble Space Telescope
Since its 1990 launch, the Hubble Space Telescope has changed our fundamental understanding of the universe.
Hubble Science
Hubble’s Galaxies
Stars
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