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Solar System

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March 23, 2019
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Ten Things to Know About Our Solar System


Our solar system is planetary system that orbits a star and all of the objects that travel around it—eight planets, dozens of moons and millions of asteroids, comets and meteoroids. Most stars host their own planets, so there are likely tens of billions of other solar systems in the Milky Way galaxy alone. We've discovered thousands of planetary systems around other stars. The planetary system we call home is located in an outer spiral arm of the vast Milky Way galaxy. It consists of the Sun (our star) and everything that orbits around it. This includes the eight planets and their natural satellites (such as our moon), dwarf planets and their satellites, as well as asteroids, comets and countless particles of smaller debris. A solar system is a star and all of the objects that travel around it—planets, moons, asteroids, comets and meteoroids. Most stars host their own planets, so there are likely tens of billions of other solar systems in the Milky Way galaxy alone. Solar systems can also have more than one star. These are called binary star systems if there are two stars, or multi-star systems if there are three or more stars. The solar system we call home is located in an outer spiral arm of the vast Milky Way galaxy. It consists of the Sun (our star) and everything that orbits around it. This includes the eight planets and their natural satellites (such as our moon), dwarf planets and their satellites, as well as asteroids, comets and countless particles of smaller debris. Size and Distance Our solar system extends much farther than the eight planets that orbit the Sun. The solar system also includes the Kuiper Belt that lies past Neptune's orbit. This is a sparsely occupied ring of icy bodies, almost all smaller than the most popular Kuiper Belt Object, dwarf planet Pluto And beyond the fringes of the Kuiper belt is the Oort Cloud. This giant spherical shell surrounds our solar system. It has never been directly observed, but its existence is predicted based on mathematical models and observations of comets that likely originate there. The Oort Cloud is made of icy pieces of space debris the sizes of mountains and sometimes larger, orbiting our Sun as far as 1.6 light years away. This shell of material is thick, extending from 5,000 astronomical units to 100,000 astronomical units. One astronomical unit (or AU) is the distance from the Sun to Earth, or about 93 million miles (150 million kilometers). The Oort Cloud is the boundary of the Sun's gravitational influence, where orbiting objects can turn around and return closer to our Sun. The Sun's heliosphere doesn't extend quite as far. The heliosphere is the bubble created by the solar wind—a stream of electrically charged gas blowing outward from the Sun in all directions. The boundary where the solar wind is abruptly slowed by pressure from interstellar gases is called the termination shock. This edge occurs between 80-100 astronomical units. Two NASA spacecraft, launched in 1977, have crossed the termination shock: Voyager 1 in 2004 and Voyager 2 in 2007. But it will be many thousands of years before the two Voyagers exit the Oort Cloud.​ Formation Our solar system formed about 4.5 billion years ago from a dense cloud of interstellar gas and dust. The cloud collapsed, possibly due to the shockwave of a nearby exploding star, called a supernova. When this dust cloud collapsed, it formed a solar nebula—a spinning, swirling disk of material. At the center, gravity pulled more and more material in. Eventually the pressure in the core was so great that hydrogen atoms began to combine and form helium, releasing a tremendous amount of energy. With that, our Sun was born, and it eventually amassed more than 99 percent of the available matter. Matter farther out in the disk was also clumping together. These clumps smashed into one another, forming larger and larger objects. Some of them grew big enough for their gravity to shape them into spheres, becoming planets, dwarf planets and large moons. In other cases, planets did not form: the asteroid belt is made of bits and pieces of the early solar system that could never quite come together into a planet. Other smaller leftover pieces became asteroids, comets, meteoroids, and small, irregular moons. Structure The order and arrangement of the planets and other bodies in our solar system is due to the way the solar system formed. Nearest the Sun, only rocky material could withstand the heat when the solar system was young. For this reason, the first four planets—Mercury, Venus, Earth and Mars—are terrestrial planets. They're small with solid, rocky surfaces. Meanwhile, materials we are used to seeing as ice, liquid or gas settled in the outer regions of the young solar system. Gravity pulled these materials together, and that is where we find gas giants Jupiter and Saturn and ice giants Uranus and Neptune. Potential for Life Our solar system is the only place we know of that harbors life, but the farther we explore the more we find potential for life in other places. Both Jupiter’s moon Europa and Saturn’s moon Enceladus have global saltwater oceans under thick, icy shells. Moons There are more than 150 known moons in our solar system and several more awaiting confirmation of discovery. Of the eight planets, Mercury and Venus are the only ones with no moons. The giant planets grab the most moons. Jupiter and Saturn have long lead our solar system’s moon counts. In some ways, the swarms of moons around these worlds resemble mini versions of our solar system. Pluto, smaller than our own moon, has five moons in its orbit, including the Charon, a moon so large it makes Pluto wobble. Even tiny asteroids can have moons. In 2017, scientists found asteroid 3122 Florence had two tiny moons. Human beings have studied our solar system for thousands of years, but it was only in the last few centuries that scientists started to really figure out how things work. The era of robotic exploration—sending uncrewed spacecraft beyond Earth as our eyes and ears—is only a little more than 55 years old. A fleet of space robots is out there right now exploring destinations from the Sun to distant planets orbiting faraway stars. DSCOVR DSCOVR (Deep Space Climate Observatory) is a space weather station that monitors changes in the solar wind, providing space weather alerts and forecasts for events like geomagnetic storms that could disrupt power grids, satellites, telecommunications, aviation and GPS. The constant stream of particles from the Sun, the solar wind, reaches DSCOVR about an hour before getting to Earth, giving forecasters 15 to 60 minutes warning time. DSCOVR orbits about a million miles from Earth in a unique location called Lagrange point 1, which basically allows it to hover between the Sun and our planet. The spacecraft’s EPIC camera takes a new picture of Earth every two hours. The EPIC camera has captured images of solar eclipses and images of the moon as it passed between DSCOVR and the Earth. It’s also photographed Earth moving between the spacecraft and the Moon. In Depth Objectives: Observe Earth from the Sun–Earth L1 Lagrange Point Spacecraft Mass: 1,257 pounds (570 kilograms) Mission Design and Management: NASA, NOAA, USAF Scientific Instruments PlasMag plasma-magnetometer (magnetometer, Faraday cup, electrostatic analyzer) Earth Polychromatic Imaging Camera (EPIC) National Institute of Standards and Technology Advanced Radiometer (NISTAR) The Deep Space Climate Observatory, or DSCOVR, gives NOAA real-time solar wind observations so that forecasters can provide early warnings about geomagnetic storms. It acts like a sensor buoy at sea that warns of an oncoming tsunami -- DSCOVR can warn forecasters 15 to 60 minutes before solar storms reach Earth. DSCOVR is a joint mission between NASA, NOAA, and the USAF designed as a successor to NASA’s Advanced Composition Explorer (ACE). The project originally was called Triana, a mission conceived in 1998 by then-Vice President Al Gore. It was meant to be a NASA Earth science mission to provide an almost continuous view of Earth from space and to use a radiometer to take direct measurements of sunlight reflected and emitted from Earth. The spacecraft originally was slated for launch on STS-107, the tragic mission of Space Shuttle Columbia in 2003, but Triana was canceled in 2001 and the satellite was put into storage. Seven years later, in 2008, the Committee on Space Environmental Sensor Mitigation Options (CSESMO) determined the spacecraft would be “the optimal solution for meeting NOAA and USAF space weather requirements.” The satellite was removed from storage in November 2008 and recertified for launch with some modifications. DSCOVR was launched on Feb.11, 2015 and 100 days later it reached the Sun–Earth L1 point and began orbiting about 1 million miles (1.5 million kilometers) from Earth. The satellite has a continuous view of the Sun and the sunlit side of Earth. It takes full Earth pictures about every 2 hours using the Earth Polychromatic Imaging Camera (EPIC) instrument. In October 2015, a website was launched that posts at least a dozen new color images every day from EPIC. On Oct. 28, 2015, NASA officially handed over control of DSCOVR to NOAA’s Space Weather Prediction Center (SWPC). The spacecraft completed its first year in deep space on Feb. 11, 2016. Real-time data from DSCOVR were made available to the public beginning July 2016. About the Mission The Deep Space Climate Observatory, or DSCOVR, will maintain the nation's real-time solar wind monitoring capabilities which are critical to the accuracy and lead time of NOAA's space weather alerts and forecasts. Without timely and accurate warnings, space weather events like the geomagnetic storms caused by changes in solar wind have the potential to disrupt nearly every major public infrastructure system, including power grids, telecommunications, aviation and GPS. DSCOVR will succeed NASA's Advanced Composition Explore's (ACE) role in supporting solar wind alerts and warnings from the L1 orbit, the neutral gravity point between the Earth and sun approximately one million miles from Earth. L1 is a good position from which to monitor the sun, because the constant stream of particles from the sun (the solar wind) reaches L1 about an hour before reaching Earth. From this position, DSCOVR will typically be able to provide 15 to 60 minute warning time before the surge of particles and magnetic field, known as a coronal mass ejection (or CME), associated with a geomagnetic storm reaches Earth. DSCOVR data will also be used to improve predictions of geomagnetic storm impact locations. Our national security and economic well-being, which depend on advanced technologies, are at risk without these advanced warnings. DSCOVR space weather data now available!!! July 27, 2016 Real-time data from DSCOVR and space weather forecasts are now available through the Space Weather Prediction Center. An archive of DSCOVR data is also accessible to users, who will be able to visualize and download the data. GOES-R ready to join DSCOVR; will provide more complete picture of space weather Set to launch November, 2016, GOES-R will also help scientists monitor space weather. Tom Berger of NOAA's Space Weather Prediction Center explains how these two satellites work together. The DSCOVR operational transition highlights the value of the NOAA and NASA team that delivered the mission to space. The partnership between the research and operational Agencies has worked well for many years and will continue with NASA providing research and NOAA providing operational space weather observations. DSCOVR Captures an EPIC Year July 22, 2016 A year after returning it's first image, NASA's EPIC camera, aboard NOAA's DSCOVR satellite, shows us an entire year from one million miles away. This video was created using NASA’s Earth Polychromatic Imaging Camera (EPIC), a four megapixel CCD camera and telescope, aboard NOAA's DSCOVR satellite. EPIC takes a new picture every two hours, revealing how the planet would look to human eyes, capturing the ever-changing motion of clouds and weather systems and the fixed features of Earth such as deserts, forests and the distinct blues of different seas. The camera has now recorded a full year of life on Earth from its orbit, seen here. A million miles away, NOAA's DSCOVR, the Nation's first operational satellite in deep space, orbits a unique location called Lagrange point 1, or L1. This orbit is a gravity neutral point in space, allowing DSCOVR to essentially hover between the sun and Earth at all times, maintaining a constant view of the sun and sun-lit side of Earth. From here, the satellite can provide advanced solar measurements and early warnings of potentially dangerous space weather events, acting as a solar storm buoy in deep space. Thanks to NASA's EPIC imager, DSCOVR's orbit also gives Earth scientists a unique vantage point for studies of the atmosphere and climate by continuously viewing the sunlit side of the planet. EPIC provides global spectral images of of Earth and insight into Earth's energy balance. EPIC's observations provide a unique angular perspective, and are used in science applications to measure ozone amounts, aerosol amounts, cloud height and phase, vegetation properties, hotspot land properties and UV radiation estimates at Earth's surface. DSCOVR Captures EPIC Eclipse NASA's EPIC camera, aboard NOAA's DSCOVR satellite, captured a unique view of this week's solar eclipse. While residents of the Western Pacific looked up in the early morning hours to observe a total eclipse of the sun, DSCOVR looked on from a million miles away and captured the shadow of the moon crossing the planet. This series of images was captured by NASA’s Earth Polychromatic Imaging Camera (EPIC), a four megapixel CCD camera and telescope on the DSCOVR satellite. A million miles away, NOAA's DSCOVR satellite is the Nation's first operational satellite in deep space. DSCOVR hovers between the sun and Earth at all times, maintaining a constant view of the sun and sun-lit side of Earth. From here, the satellite can provide advanced solar measurements and early warnings of potentially dangerous space weather events, acting as a solar storm buoy in deep space. NASA's EPIC imager also gives Earth scientists a unique vantage point for studies of the atmosphere and climate by continuously viewing the sunlit side of the planet. The EPIC imager provides global spectral images of Earth and insight into Earth's energy balance. EPIC's observations provide a unique angular perspective, and will be used in science applications to measure ozone amounts, aerosol amounts, cloud height and phase, vegetation properties, hotspot land properties and UV radiation estimates at Earth's surface. DSCOVR completes its first year in deep space! Launched one year ago, on February 11, 2015, DSCOVR – the nation’s first operational satellite in deep space – is now orbiting one million miles away and will soon become America’s primary warning system for solar magnetic storms and solar wind data while giving Earth scientists a unique vantage point for studies of the planet's atmosphere and climate. Earlier today, NOAA officially took command of its Deep Space Climate Observatory (DSCOVR) satellite. NASA, in charge of both the launch and activation of the satellite, has officially handed over satellite operations to NOAA’s DSCOVR team. Next, the team will optimize the final space weather instrument settings and the satellite will soon begin normal operation. Launched February 11, 2015, DSCOVR – the nation’s first operational satellite in deep space – is set to replace NASA’s 17-year old ACE research satellite as America’s primary warning system for solar magnetic storms and solar wind data. (ACE will continue its role in space weather research). DSCOVR will give NOAA’s Space Weather Prediction Center (SWPC) forecasters higher-quality measurements of solar wind conditions, improving their ability to monitor and warn of severe and potentially dangerous space weather events. Like a sensor buoy at sea can warn us of on oncoming tsunami, DSCOVR will be able to provide warnings 15 to 60 minutes before solar storms reach Earth. A million miles away, DSCOVR orbits a unique location called Lagrange point 1, or L1. This point is a gravity neutral point in space, allowing DSCOVR to essentially hover between the sun and Earth at all times. DSCOVR will be our eyes on the sun, and give us early warning when it detects a surge of energy that could trigger a geomagnetic storm destined for Earth,” said Stephen Volz, Ph.D., assistant administrator for NOAA’s Satellite and Information Service. Early warnings are crucial because solar storms have the potential to produce major disruptions to our infrastructure here on Earth. The most severe solar storms start with a huge magnetic eruption on the Sun that is first seen as a solar flare. X-rays produced in the flare inflame the Earth’s ionosphere and can disrupt high-frequency radio communications like those used in commercial aviation to communicate with aircraft. The eruption can also cause a “coronal mass ejection,” sending enormous clouds of magnetic plasma that can cause strong electrical currents in the ionosphere and inside the Earth, disrupting electrical power grids, corroding gas and oil pipelines, and impeding the use of the Global Positioning System (GPS) by search-and-rescue crews. In 2013, a Lloyds of London study predicted that the most extreme space weather storms could affect 20 to 40 million people in the U.S. and cause up to $2.6 trillion in damages, with recovery taking up to two years. Outside of our atmosphere, these solar storms can harm astronauts and the equipment they rely on to survive. In fact, in 1972 a solar flare came within months of disrupting the last two Apollo missions to the moon! In addition to its space weather instrument suite, DSCOVR is flying two NASA Earth-observing instruments, known as NISTAR and EPIC, which will gather a range of measurements, from ozone and aerosol amounts to changes in Earth's radiation. Daily views of Earth from NASA’s EPIC can be seen at http://epic.gsfc.nasa.gov. DSCOVR is a partnership between NOAA, NASA and the U.S. Air Force. NOAA is operating DSCOVR from its NOAA Satellite Operations Facility in Suitland, Maryland, and will process the space weather data at SWPC in Boulder, Colorado. From there, the SWPC will distribute the DSCOVR data to users within the United States and around the world. The data will be archived at NOAA’s National Geophysical Data Center, also in Boulder. NOAA funded NASA to refurbish the DSCOVR satellite and its solar wind instruments, develop the command and control portion of the ground segment, and manage the launch and activation of the satellite. The Air Force funded and managed the Falcon 9 launch services for DSCOVR. Data from the NASA-funded secondary sensors for Earth and space science observations will be processed at NASA’s DSCOVR Science Operations Center and archived and distributed by NASA’s Atmospheric Science Data Center.