Tag Archives: Earth

NASA Space Place – Solar Wind Creates — And Whips — A Magnetic Tail Around Earth

Poster’s Note: One of the many under-appreciated aspects of NASA is the extent to which it publishes quality science content for children and Ph.D.’s alike. NASA Space Place has been providing general audience articles for quite some time that are freely available for download and republishing. Your tax dollars help promote science! The following article was provided for reprinting in August, 2015.

By Dr. Ethan Siegel

2013february2_spaceplaceAs Earth spins on its axis, our planet’s interior spins as well. Deep inside our world, Earth’s metal-rich core produces a magnetic field that spans the entire globe, with the magnetic poles offset only slightly from our rotational axis. If you fly up to great distances, well above Earth’s surface, you’ll find that this magnetic web, called the magnetosphere, is no longer spherical. It not only bends away from the direction of the sun at high altitudes, but it exhibits some very strange features, all thanks to the effects of our parent star.

The sun isn’t just the primary source of light and heat for our world; it also emits an intense stream of charged particles, the solar wind, and has its own intense magnetic field that extends much farther into space than our own planet’s does. The solar wind travels fast, making the 150 million km (93 million mile) journey to our world in around three days, and is greatly affected by Earth. Under normal circumstances, our world’s magnetic field acts like a shield for these particles, bending them out of the way of our planet and protecting plant and animal life from this harmful radiation.

But for every action, there’s an equal and opposite reaction: as our magnetosphere bends the solar wind’s ions, these particles also distort our magnetosphere, creating a long magnetotail that not only flattens and narrows, but whips back-and-forth in the onrushing solar wind. The particles are so diffuse that collisions between them practically never occur, but the electromagnetic interactions create waves in Earth’s magnetosphere, which grow in magnitude and then transfer energy to other particles. The charged particles travel within the magnetic field toward both poles, and when they hit the ionosphere region of Earth’s upper atmosphere, they collide with ions of oxygen and nitrogen causing aurora. Missions such as the European Space Agency and NASA Cluster mission have just led to the first accurate model and understanding of equatorial magnetosonic waves, one such example of the interactions that cause Earth’s magnetotail to whip around in the wind like so.

The shape of Earth’s magnetic field not only affects aurorae, but can also impact satellite electronics. Understanding its shape and how the magnetosphere interacts with the solar wind can also lead to more accurate predictions of energetic electrons in near-Earth space that can disrupt our technological infrastructure. As our knowledge increases, we may someday be able to reach one of the holy grails of connecting heliophysics to Earth: forecasting and accurately predicting space weather and its effects. Thanks to the Cluster Inner Magnetosphere Campaign, Van Allen Probes, Mars Odyssey Thermal Emission Imaging System, Magnetospheric Multiscale, and Heliophysics System Observatory missions, we’re closer to this than ever before.

Kids can learn about how solar wind defines the edges of our solar system at NASA Space Place – spaceplace.nasa.gov/interstellar

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Caption: Composite of 25 images of the sun, showing solar outburst/activity over a 365 day period; NASA / Solar Dynamics Observatory / Atmospheric Imaging Assembly / S. Wiessinger; post-processing by E. Siegel.

This article was provided by the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration.

About NASA Space Place

The goal of the NASA Space Place is “to inform, inspire, and involve children in the excitement of science, technology, and space exploration.” More information is available at their website: http://spaceplace.nasa.gov/

NASA Space Place – No Surprise! Earth’s Strongest Gravity Lies Atop The Highest Mountains

Poster’s Note: One of the many under-appreciated aspects of NASA is the extent to which it publishes quality science content for children and Ph.D.’s alike. NASA Space Place has been providing general audience articles for quite some time that are freely available for download and republishing. Your tax dollars help promote science! The following article was provided for reprinting in April, 2014.

By Dr. Ethan Siegel

2013february2_spaceplacePut more mass beneath your feet and feel the downward acceleration due to gravity increase. Newton’s law of universal gravitation may have been superseded by Einstein’s, but it still describes the gravitational force and acceleration here on Earth to remarkable precision. The acceleration you experience is directly proportional to the amount of mass you “see,” but inversely proportional to the distance from you to that mass squared.

The denser the mass beneath your feet, the stronger the gravitational force, and when you are closer to such a mass, the force is even greater. At higher elevations or even higher altitudes, you’d expect your gravitational force to drop as you move farther from Earth’s center. You’d probably also expect that downward acceleration to be greater if you stood atop a large mountain than if you flew tens of thousands of feet above a flat ocean, with nothing but ultra-light air and liquid water beneath you for all those miles. In fact this is true, but not just due to the mountain’s extra mass!

Earth is built like a layer-cake, with the less dense atmosphere, ocean, and crust floating atop the denser mantle, which in turn floats atop the outer and inner cores of our planet. An iceberg’s buoyancy is enough to lift only about one tenth of it above the sea, with the other nine tenths below the surface. Similarly, each and every mountain range has a corresponding “invisible mountain” that dips deep into the mantle. Beneath the ocean floor, Earth’s crust might be only three to six miles thick, but it can exceed 40 miles in thickness around major mountain ranges like the Himalayas and the Andes. It’s where one of Earth’s tectonic plates subducts beneath another that we see the largest gravitational anomalies: another confirmation of the theory of continental drift.

A combination of instruments aboard NASA’s Gravity Recovery and Climate Experiment (GRACE) satellites, including the SuperSTAR accelerometer, the K-band ranging system and the onboard GPS receiver, have enabled the construction of the most accurate map of Earth’s gravitational field ever: to accelerations of nanometers per second squared. While the mountaintops may be farther from Earth’s center than any other point, the extra mass of the mountains and their roots – minus the mass of the displaced mantle – accounts for the true gravitational accelerations we actually see. It’s only by the grace of these satellites that we can measure this to such accuracy and confirm what was first conjectured in the 1800s: that the full layer-cake structure of Earth must be accounted for to explain the gravity we experience on our world!

This article was provided by the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration.

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Image credit: NASA / GRACE mission / Christoph Reigber, et al. (2005): An Earth gravity field model complete to degree and order 150 from GRACE: EIGEN-GRACE02S, Journal of Geodynamics 39(1),1–10. Reds indicate greater gravitational anomalies; blues are smaller ones.

About NASA Space Place

The goal of the NASA Space Place is “to inform, inspire, and involve children in the excitement of science, technology, and space exploration.” More information is available at their website: http://spaceplace.nasa.gov/

NASA Space Place – The “G” In GOES Is What Makes It Go

Poster’s Note: One of the many under-appreciated aspects of NASA is the extent to which it publishes quality science content for children and Ph.D.’s alike. NASA Space Place has been providing general audience articles for quite some time that are freely available for download and republishing. Your tax dollars help promote science! The following article was provided for reprinting in May, 2015.

By Dr. Ethan Siegel

2013february2_spaceplaceGoing up into space is the best way to view the universe, eliminating all the distortionary effects of weather, clouds, temperature variations and the atmosphere’s airflow all in one swoop. It’s also the best way, so long as you’re up at high enough altitudes, to view an entire 50 percent of Earth all at once. And if you place your observatory at just the right location, you can observe the same hemisphere of Earth continuously, tracking the changes and behavior of our atmosphere for many years.

The trick, believe it or not, was worked out by Kepler some 400 years ago! The same scientist who discovered that planets orbit the sun in ellipses also figured out the relationship between how distant an object needs to be from a much more massive one in order to have a certain orbital period. All you need to know is the period and distance of one satellite for any given body, and you can figure out the necessary distance to have any desired period. Luckily for us, planet Earth has a natural satellite—the moon—and just from that information, we can figure out how distant an artificial satellite would need to be to have an orbital period that exactly matches the length of a day and the rotational speed of Earth. For our world, that means an orbital distance of 42,164 km (26,199 miles) from Earth’s center, or 35,786 km (22,236 miles) above mean sea level.

We call that orbit geosynchronous or geostationary, meaning that a satellite at that distance always remains above the exact same location on our world. Other effects—like solar wind, radiation pressure and the moon—require onboard thrusters to maintain the satellite’s precisely desired position above any given point on Earth’s surface. While geostationary satellites have been in use since 1963, it was only in 1974 that the Synchronous Meteorological Satellite (SMS) program began to monitor Earth’s weather with them, growing into the Geostationary Operational Environmental Satellite (GOES) program the next year. For 40 years now, GOES satellites have monitored the Earth’s weather continuously, with a total of 16 satellites having been launched as part of the program. To the delight of NASA (and Ghostbusters) fans everywhere, GOES-R series will launch in 2016, with thrice the spectral information, four times the spatial resolution and five times the coverage speed of its predecessors, with many other improved capabilities. Yet it’s the simplicity of gravity and the geostationary “G” in GOES that gives us the power to observe our hemisphere all at once, continuously, and for as long as we like!

This article was provided by the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration.

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Caption: National Oceanic and Atmospheric Administration, of the first image ever obtained from a GOES satellite. This image was taken from over 22,000 miles (35,000 km) above the Earth’s surface on October 25, 1975.

About NASA Space Place

The goal of the NASA Space Place is “to inform, inspire, and involve children in the excitement of science, technology, and space exploration.” More information is available at their website: http://spaceplace.nasa.gov/

NASA News Digest: Space Science For 7 April – 16 April 2015

Greetings fellow astrophiles,

The NASA News service provides up-to-date announcements of NASA policy, news events, and space science. A recent selection of space science articles are provided below, including direct links to the full announcements. Those interested in receiving these news announcements directly from NASA can subscribe to their service by sending an email to:

hqnews-request@newsletters.nasa.gov?subject=subscribe

NASA Joins Forces To Put Satellite Eyes On Threat To U.S. Freshwater

RELEASE 15-058 (Click here for the full article) – 7 April 2015

IDL TIFF fileNASA has joined forces with the U.S. Environmental Protection Agency, National Oceanic and Atmospheric Administration, and U.S. Geological Survey to transform satellite data designed to probe ocean biology into information that will help protect the American public from harmful freshwater algal blooms.

Algal blooms are a worldwide environmental problem causing human and animal health risks, fish kills, and taste and odor in drinking water. In the United States, the cost of freshwater degraded by harmful algal blooms is estimated at $64 million annually. In August 2014, officials in Toledo, Ohio, banned the use of drinking water supplied to more than 400,000 residents after it was contaminated by an algal bloom in Lake Erie.

The new $3.6 million, multi-agency effort will use ocean color satellite data to develop an early warning indicator for toxic and nuisance algal blooms in freshwater systems and an information distribution system to aid expedient public health advisories.

“The vantage point of space not only contributes to a better understanding of our home planet, it helps improve lives around the world,” said NASA Administrator Charles Bolden. “We’re excited to be putting NASA’s expertise in space and scientific exploration to work protecting public health and safety.”

For more information on NASA’s Earth science activities, visit: www.nasa.gov/earth

NASA, USGS Begin Work On Landsat 9 To Continue Land Imaging Legacy

RELEASE 15-061 (Click here for the full article) – 16 April 2015

15-061NASA and the U.S. Geological Survey (USGS) have started work on Landsat 9, planned to launch in 2023, which will extend the Earth-observing program’s record of land images to half a century.

The Landsat program has provided accurate measurements of Earth’s land cover since 1972. With data from Landsat satellites, ecologists have tracked deforestation in South America, water managers have monitored irrigation of farmland in the American West, and researchers have watched the growth of cities worldwide. With the help of the program’s open archive, firefighters have assessed the severity of wildfires and scientists have mapped the retreat of mountain glaciers.

The President’s fiscal year 2016 budget calls for initiation of a Landsat 9 spacecraft as an upgraded rebuild of Landsat 8, as well as development of a low-cost thermal infrared (TIR) free-flying satellite for launch in 2019 to reduce the risk of a data gap in this important measurement. The TIR free flyer will ensure data continuity by flying in formation with Landsat 8. The budget also calls for the exploration of technology and systems innovations to provide more cost effective and advanced capabilities in future land-imaging missions beyond Landsat 9, such as finding ways to miniaturize instruments to be launched on smaller, less expensive satellites.

For more information on NASA’s Earth science activities, visit: www.nasa.gov/earth

For more information on the Landsat program, visit: landsat.gsfc.nasa.gov and landsat.usgs.gov

NASA Spacecraft Achieves Unprecedented Success Studying Mercury

RELEASE 15-067 (Click here for the full article) – 16 April 2015

2015april16_messengerstillAfter extraordinary science findings and technological innovations, a NASA spacecraft launched in 2004 to study Mercury will impact the planet’s surface, most likely on April 30, after it runs out of propellant.

NASA’s MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft will impact the planet at more than 8,750 miles per hour (3.91 kilometers per second) on the side of the planet facing away from Earth. Due to the expected location, engineers will be unable to view in real time the exact location of impact.

On Tuesday, mission operators in mission control at the Johns Hopkins University Applied Physics Laboratory (APL) in Laurel, Maryland, completed the fourth in a series of orbit correction maneuvers designed to delay the spacecraft’s impact into the surface of Mercury. The last maneuver is scheduled for Friday, April 24.

“Following this last maneuver, we will finally declare the spacecraft out of propellant, as this maneuver will deplete nearly all of our remaining helium gas,” said Daniel O’Shaughnessy, mission systems engineer at APL. “At that point, the spacecraft will no longer be capable of fighting the downward push of the sun’s gravity.”

For a complete listing of science findings and technological achievements of the mission visit: www.nasa.gov/messenger

NASA Spacecraft Achieves Unprecedented Success Studying Mercury

RELEASE M15-061 (Click here for the full article) – 16 April 2015

m15-061bNASA is celebrating the Hubble Space Telescope’s 25th anniversary with a variety of events highlighting its groundbreaking achievements and scientific contributions with activities running April 20-26.

Hubble, the world’s first space telescope, was launched on April 24, 1990 aboard the space shuttle Discovery. In its quarter-century in orbit, the observatory has transformed our understanding of our solar system and beyond, and helped us find our place among the stars.

Starting at midnight EDT on Monday, April 20, and running through Sunday, April 26, images taken by the Hubble Space Telescope will be broadcast several times each hour on the Toshiba Vision dual LED screens in Times Square, New York.

The IMAX movie Hubble 3D is playing at select theatres across the United States throughout April. Hubble images come to vast, three-dimensional life, taking audiences through the telescope’s 25-year existence and putting them in orbit with astronauts during the latest servicing mission. For more information and the trailer, visit: hubblesite.org/hubble_20/imax_hubble_3d/

For NASA TV streaming video, schedules and downlink information, visit: www.nasa.gov/nasatv

For more Hubble 25th Anniversary events, visit: www.hubble25th.org

For more information about NASA’s Hubble Space Telescope, visit: www.nasa.gov/hubble

NASA News Digest: Space Science For 15 March – 26 March 2015

Greetings fellow astrophiles,

The NASA News service provides up-to-date announcements of NASA policy, news events, and space science. A recent selection of space science articles are provided below, including direct links to the full announcements. Those interested in receiving these news announcements directly from NASA can subscribe to their service by sending an email to:

hqnews-request@newsletters.nasa.gov?subject=subscribe

New Desktop Application Has Potential To Increase Asteroid Detection, Now Available To Public

RELEASE 15-041 (Click here for the full article) – 15 March 2015

2015april2_15_041A software application based on an algorithm created by a NASA challenge has the potential to increase the number of new asteroid discoveries by amateur astronomers.

Analysis of images taken of our solar system’s main belt asteroids between Mars and Jupiter using the algorithm showed a 15 percent increase in positive identification of new asteroids.

During a panel Sunday at the South by Southwest Festival in Austin, Texas, NASA representatives discussed how citizen scientists have made a difference in asteroid hunting. They also announced the release of a desktop software application developed by NASA in partnership with Planetary Resources, Inc., of Redmond, Washington. The application is based on an Asteroid Data Hunter-derived algorithm that analyzes images for potential asteroids. It’s a tool that can be used by amateur astronomers and citizen scientists.

The new asteroid hunting application can be downloaded at: topcoder.com/asteroids

For information about NASA’s Asteroid Grand Challenge, visit: www.nasa.gov/asteroidinitiative

NASA Spacecraft Detects Aurora And Mysterious Dust Cloud Around Mars

RELEASE 15-045 (Click here for the full article) – 18 March 2015

2015april2_15_045aNASA’s Mars Atmosphere and Volatile Evolution (MAVEN) spacecraft has observed two unexpected phenomena in the Martian atmosphere: an unexplained high-altitude dust cloud and aurora that reaches deep into the Martian atmosphere.

The presence of the dust at orbital altitudes from about 93 miles (150 kilometers) to 190 miles (300 kilometers) above the surface was not predicted. Although the source and composition of the dust are unknown, there is no hazard to MAVEN and other spacecraft orbiting Mars.

“If the dust originates from the atmosphere, this suggests we are missing some fundamental process in the Martian atmosphere,” said Laila Andersson of the University of Colorado’s Laboratory for Atmospherics and Space Physics (CU LASP), Boulder, Colorado.

For images related to the findings, visit: http://www.nasa.gov/maven

NASA’s SOFIA Finds Missing Link Between Supernovae And Planet Formation

RELEASE 15-044 (Click here for the full article) – 19 March 2015

2015april2_15_044aUsing NASA’s Stratospheric Observatory for Infrared Astronomy (SOFIA), an international scientific team discovered that supernovae are capable of producing a substantial amount of the material from which planets like Earth can form.

These findings are published in the March 19 online issue of Science magazine.

“Our observations reveal a particular cloud produced by a supernova explosion 10,000 years ago contains enough dust to make 7,000 Earths,” said Ryan Lau of Cornell University in Ithaca, New York.

The research team, headed by Lau, used SOFIA’s airborne telescope and the Faint Object InfraRed Camera for the SOFIA Telescope, FORCAST, to take detailed infrared images of an interstellar dust cloud known as Supernova Remnant Sagittarius A East, or SNR Sgr A East.

For more information about SOFIA, visit: www.nasa.gov/sofia or www.dlr.de/en/sofia

For information about SOFIA’s science mission and scientific instruments, visit: www.sofia.usra.edu or www.dsi.uni-stuttgart.de/index.en.html

NASA’s Opportunity Mars Rover Finishes Marathon, Clocks In At Just Over 11 Years

RELEASE 15-049 (Click here for the full article) – 24 March 2015

2015april2_15_049cThere was no tape draped across a finish line, but NASA is celebrating a win. The agency’s Mars Exploration Rover Opportunity completed its first Red Planet marathon Tuesday — 26.219 miles (42.195 kilometers) – with a finish time of roughly 11 years and two months.

“This is the first time any human enterprise has exceeded the distance of a marathon on the surface of another world,” said John Callas, Opportunity project manager at NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, California. “A first time happens only once.”

The rover team at JPL plans a marathon-length relay run at the laboratory next week to celebrate.

The long-lived rover surpassed the marathon mark during a drive of 153 feet (46.5 meters). Last year, Opportunity became the long-distance champion of all off-Earth vehicles when it topped the previous record set by the former Soviet Union’s Lunokhod 2 moon rover.

For more information about Opportunity, visit www.nasa.gov/rovers

Follow the project on social media at: twitter.com/MarsRovers and www.facebook.com/mars.rovers

NASA’s Hubble, Chandra Find Clues That May Help Identify Dark Matter

RELEASE 15-046 (Click here for the full article) – 26 March 2015

2015april2_15_046Using observations from NASA’s Hubble Space Telescope and Chandra X-ray Observatory, astronomers have found that dark matter does not slow down when colliding with itself, meaning it interacts with itself less than previously thought. Researchers say this finding narrows down the options for what this mysterious substance might be.

Dark matter is an invisible matter that makes up most of the mass of the universe. Because dark matter does not reflect, absorb or emit light, it can only be traced indirectly by, such as by measuring how it warps space through gravitational lensing, during which the light from a distant source is magnified and distorted by the gravity of dark matter.

To learn more about dark matter and test such theories, researchers study it in a way similar to experiments on visible matter — by watching what happens when it bumps into other objects. In this case, the colliding objects under observation are galaxy clusters.

For images and more information about the Hubble Space Telescope, visit: www.nasa.gov/hubble

For more Chandra images, multimedia and related materials, visit: www.nasa.gov/mission_pages/chandra/main