Solar System: 10 Things To Know This Week
Solar System: 10 Things to Know This Week
The Living Planet Edition
Whether it's crops, forests or phytoplankton blooms in the ocean, our scientists are tracking life on Earth. Just as satellites help researchers study the atmosphere, rainfall and other physical characteristics of the planet, the ever-improving view from above allows them to study Earth's interconnected life.
1. Life on Earth, From Space
While we (NASA) began monitoring life on land in the 1970s with the Landsat satellites, this fall marks 20 years since we've continuously observed all the plant life at the surface of both the land and ocean. The above animation captures the entirety of two decades of observations.
2. Watching the World Breathe
With the right tools, we can see Earth breathe. With early weather satellite data in the 1970s and '80s, NASA Goddard scientist Compton Tucker was able to see plants' greening and die-back from space. He developed a way of comparing satellite data in two wavelengths.
When healthy plants are stocked with chlorophyll and ready to photosynthesize to make food (and absorb carbon dioxide), leaves absorb red light but reflect infrared light back into space. By comparing the ratio of red to infrared light, Tucker and his colleagues could quantify vegetation covering the land.
Expanding the study to the rest of the globe, the scientists could track rainy and dry seasons in Africa, see the springtime blooms in North America, and wildfires scorching forests worldwide.
3. Like Breathing? Thank Earth's Ocean
But land is only part of the story. The ocean is home to 95 percent of Earth's living space, covering 70 percent of the planet and stretching miles deep. At the base of the ocean's food web is phytoplankton - tiny plants that also undergo photosynthesis to turn nutrients and carbon dioxide into sugar and oxygen. Phytoplankton not only feed the rest of ocean life, they absorb carbon dioxide - and produce about half the oxygen we breathe.
In the Arctic Ocean, an explosion of phytoplankton indicates change. As seasonal sea ice melts, warming waters and more sunlight will trigger a sudden, massive phytoplankton bloom that feeds birds, sea lions and newly-hatched fish. But with warming atmospheric temperatures, that bloom is now happening several weeks earlier - before the animals are in place to take advantage of it.
4. Keeping an Eye on Crops
The "greenness" measurement that scientists use to measure forests and grasslands can also be used to monitor the health of agricultural fields. By the 1980s, food security analysts were approaching NASA to see how satellite images could help with the Famine Early Warning System to identify regions at risk - a partnership that continues today.
With rainfall estimates, vegetation measurements, as well as the recent addition of soil moisture information, our scientists can help organizations like USAID direct emergency help.
The view from space can also help improve agricultural practices. A winery in California, for example, uses individual pixels of Landsat data to determine when to irrigate and how much water to use.
5. Coming Soon to the International Space Station
A laser-based instrument being developed for the International Space Station will provide a unique 3-D view of Earth's forests. The instrument, called GEDI, will be the first to systematically probe the depths of the forests from space.
Another ISS instrument in development, ECOSTRESS, will study how effectively plants use water. That knowledge provided on a global scale from space will tell us "which plants are going to live or die in a future world of greater droughts," said Josh Fisher, a research scientist at NASA's Jet Propulsion Laboratory and science lead for ECOSTRESS.
6. Seeing Life, From the Microscopic to Multicellular
Scientists have used our vantage from space to study changes in animal habitats, track disease outbreaks, monitor forests and even help discover a new species. Bacteria, plants, land animals, sea creatures and birds reveal a changing world.
Our Black Marble image provides a unique view of human activity. Looking at trends in our lights at night, scientists can study how cities develop over time, how lighting and activity changes during certain seasons and holidays, and even aid emergency responders during power outages caused by natural disasters.
7. Earth as Analog and Proving Ground
Just as our Mars rovers were tested in Earth's deserts, the search for life on ocean moons in our solar system is being refined by experiments here. JPL research scientist Morgan Cable looks for life on the moons of Jupiter and Saturn. She cites satellite observations of Arctic and Antarctic ice fields that are informing the planning for a future mission to Europa, an icy moon of Jupiter.
The Earth observations help researchers find ways to date the origin of jumbled, chaotic ice. "When we visit Europa, we want to go to very young places, where material from that ocean is being expressed on the surface," she explained. "Anywhere like that, the chances of finding biomarkers goes up - if they're there."
8. Only One Living Planet
Today, we know of only one living planet: our own. The knowledge and tools NASA developed to study life here are among our greatest assets as we begin the search for life beyond Earth.
There are two main questions: With so many places to look, how can we home in on the places most likely to harbor life? What are the unmistakable signs of life - even if it comes in a form we don't fully understand? In this early phase of the search, "We have to go with the only kind of life we know," said Tony del Genio, co-lead of a new NASA interdisciplinary initiative to search for life on other worlds.
So, the focus is on liquid water. Even bacteria around deep-sea vents that don't need sunlight to live need water. That one necessity rules out many planets that are too close or too far from their stars for water to exist, or too far from us to tell. Our Galileo and Cassini missions revealed that some moons of Jupiter and Saturn are not the dead rocks astronomers had assumed, but appear to have some conditions needed for life beneath icy surfaces.
9. Looking for Life Beyond Our Solar System
In the exoplanet (planets outside our solar system that orbit another star) world, it's possible to calculate the range of distances for any star where orbiting planets could have liquid water. This is called the star's habitable zone. Astronomers have already located some habitable-zone planets, and research scientist Andrew Rushby of NASA Ames Research Center is researching ways to refine the search. "An alien would spot three planets in our solar system in the habitable zone [Earth, Mars and Venus]," Rushby said, "but we know that 67 percent of those planets are not inhabited."
He recently developed a model of Earth's carbon cycle and combined it with other tools to study which planets in habitable zones would be the best targets to look for life, considering probable tectonic activity and water cycles. He found that larger planets are more likely than smaller ones to have surface temperatures conducive to liquid water. Other exoplanet researchers are looking for rocky worlds, and biosignatures, the chemical signs of life.
10. You Can Learn a Lot from a Dot
When humans start collecting direct images of exoplanets, even the closest ones will appear as only a handful of pixels in the detector - something like the famous "blue dot" image of Earth from Saturn. What can we learn about life on these planets from a single dot?
Stephen Kane of the University of California, Riverside, has come up with a way to answer that question by using our EPIC camera on NOAA's DSCOVR satellite. "I'm taking these glorious pictures and collapsing them down to a single pixel or handful of pixels," Kane explained. He runs the light through a noise filter that attempts to simulate the interference expected from an exoplanet mission. By observing how the brightness of Earth changes when mostly land is in view compared with mostly water, Kane reverse-engineers Earth's rotation rate - something that has yet to be measured directly for exoplanets.
The most universal, most profound question about any unknown world is whether it harbors life. The quest to find life beyond Earth is just beginning, but it will be informed by the study of our own living planet.
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Solar System: 10 Things to Know This Week
Rockets We Love-Saturn V
Fifty years ago, with President Kennedy’s Moon landing deadline looming, the powerful Saturn V had to perform. And perform it did—hurling 24 humans to the Moon.
The race to land astronauts on the Moon was getting tense 50 years ago this week. Apollo 6, the final uncrewed test flight of America’s powerful Moon rocket, launched on April 4, 1968. Several technical issues made for a less-than-perfect launch, but the test flight nonetheless convinced NASA managers that the rocket was up to the task of carrying humans. Less than two years remained to achieve President John F. Kennedy’s goal to put humans on the Moon before the decade was out, meaning the Saturn V rocket had to perform.
1—“The only chance to get to the Moon before the end of 1969.”
After the April 1968 Apollo 6 test flight (pictured above), the words of Deke Slayton (one of the original Mercury 7 astronauts) and intense competition with a rival team in the Soviet Union propelled a 12-member panel to unanimously vote for a Christmas 1968 crewed mission to orbit the Moon.
2—Four Hundred Elephants...
The Saturn V rocket stood about the height of a 36-story-tall building, and 60 feet (18 meters) taller than the Statue of Liberty. Fully fueled for liftoff, the Saturn V weighed 6.2 million pounds (2.8 million kilograms), or the weight of about 400 elephants.
3—...and Busloads of Thrust
Stand back, Ms. Frizzle. The Saturn V generated 7.6 million pounds (34.5 million newtons) of thrust at launch, creating more power than 85 Hoover Dams. It could launch about 130 tons (118,000 kilograms) into Earth orbit. That's about as much weight as 10 school buses. The Saturn V could launch about 50 tons (43,500 kilograms) to the Moon. That's about the same as four school buses.
4—Christmas at the Moon
On Christmas Eve 1968, the Saturn V delivered on engineers’ promises by hurling Frank Borman, Jim Lovell and Bill Anders into lunar orbit. The trio became the first human beings to orbit another world. The Apollo 8 crew broadcast a special holiday greeting from lunar orbit and also snapped the iconic earthrise image of our home planet rising over the lunar landscape.
5—Gumdrop and Spider
The crew of Apollo 9 proved that they could pull the lunar module out of the top of the Saturn V’s third stage and maneuver it in space (in this case high above Earth). The crew named their command module “Gumdrop.” The Lunar Module was named “Spider.”
6—The Whole Enchilada
Saturn-V AS-505 provided the ride for the second dry run to the Moon in 1969. Tom Stafford, Gene Cernan and John Young rode Command Module “Charlie Brown” to lunar orbit and then took Lunar Module “Snoopy” on a test run in lunar orbit. Apollo 10 did everything but land on the Moon, setting the stage for the main event a few months later. Young and Cernan returned to walk on the Moon aboard Apollo 16 and 17 respectively. Cernan, who died in 2017, was the last human being (so far) to set foot on the Moon.
7—The Main Event
The launch of Apollo 11—the first mission to land humans on the Moon—provided another iconic visual as Saturn-V AS-506 roared to life on Launch Pad 39A at Kennedy Space Center in Florida. Three days later, Neil Armstrong and Buzz Aldrin made the first of many bootprints in the lunar dust (supported from orbit by Michael Collins).
8—Moon Men
Saturn V rockets carried 24 humans to the Moon, and 12 of them walked on its surface between 1969 and 1972. Thirteen are still alive today. The youngest, all in their early 80s, are moonwalkers Charles Duke (Apollo 16) and Harrison Schmitt (Apollo 17) and Command Module Pilot Ken Mattingly (Apollo 16, and also one of the heroes who helped rescue Apollo 13). There is no single image of all the humans who have visited the Moon.
9—The Flexible Saturn V
The Saturn V’s swan song was to lay the groundwork for establishing a permanent human presence in space. Skylab, launched into Earth orbit in 1973, was America’s first space station, a precursor to the current International Space Station. Skylab’s ride to orbit was a Saturn IV-B 3rd stage, launched by a Saturn 1-C and SII Saturn V stages.
This was the last launch of a Saturn V, but you can still see the three remaining giant rockets at the visitor centers at Johnson Space Center in Texas and Kennedy Space Center in Florida and at the United States Space and Rocket Center in Alabama (near Marshall Space Flight Center, one of the birthplaces of the Saturn V).
10—The Next Generation
The Saturn V was retired in 1973. Work is now underway on a fleet of rockets. We are planning an uncrewed flight test of Space Launch System (SLS) rocket to travel beyond the Moon called Exploration Mission-1 (EM-1). “This is a mission that truly will do what hasn’t been done and learn what isn’t known,” said Mike Sarafin, EM-1 mission manager at NASA Headquarters in Washington.
Read the web version of this 10 Things to Know article HERE.
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Did the training ever get so hard that you would regret getting into this?
No because the end goal is space!
Astronaut in the house!
Air Force Colonel and NASA Astronaut Nick Hague is back from his seven month stay aboard the space station and ready to answer your questions in today's Tumblr Answer Time!
Let's get started.
O_o When we peer deep into space, we don't expect to find something staring back at us...
This galactic ghoul, captured by our Hubble Space Telescope, is actually a titanic head-on collision between two galaxies. Each "eye" is the bright core of a galaxy, one of which slammed into another. The outline of the face is a ring of young blue stars. Other clumps of new stars form a nose and mouth.
Although galaxy collisions are common most of them are not head-on smashups like this Arp-Madore system. Get spooked & find out what lies inside this ghostly apparition, here.
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Your Gut in Space
Finding the Right Balance for the Microbiota
Trillions of microorganisms live on and in the human body, many of them essential to its function and health. These organisms, collectively known as the microbiota, outnumber cells in the body by at least five times.
Microorganisms in the intestinal tract, the gut microbiota, play an especially important role in human health. An investigation on the International Space Station, Rodent Research-7 (RR-7), studies how the gut microbiota changes in response to spaceflight, and how that change in turn affects the immune system, metabolic system, and circadian or daily rhythms.
Research shows that the microbiota in the mammalian digestive tract has a major impact on an individual’s physiology and behavior. In humans, disruption of microbial communities has been linked to multiple health problems affecting intestinal, immune, mental and metabolic systems.
The investigation compares two different genetic strains of mice and two different durations of spaceflight. Twenty mice, ten of each strain, launch to the space station, and another 20 remain on the ground in identical conditions (except, of course, for the absence of gravity). Mice are a model organism that often serves as a scientific stand-in for other mammals and humans.
Fecal material collected from the mice every two weeks will be examined for changes in the gut microbiota. Researchers plan to analyze fecal and tissue samples after 30 and 90 days of flight to compare the effects of different durations of time in space.
With a better understanding of relationships between changes such as disruption in sleep and an imbalance of microbial populations, researchers can identify specific factors that contribute to changes in the microbiota. Further studies then can determine proactive measures and countermeasures to protect astronaut health during long-term missions.
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Satellite Data in Ag-tion: From Space to Your Plate
As Earth’s climate changes, some places are drying out and others are getting wetter, including the land that produces the food we eat. Farmers have to figure out how to adapt to changing climate conditions.
Our fleet of satellites has been watching over Earth for more than half a century. Some, like our joint Landsat mission with the U.S. Geological Survey (USGS), collect valuable data about the crops that make up our food supply and the water it takes to grow them.
Combining this wealth of satellite data with observations on the ground allows us to track how crop production changes over the years.
For example, this map shows how croplands have changed over the years to feed a growing population. The Agriculture Department (USDA) has used Landsat data since 2008 to track crops growing in the continental United States.
Agricultural scientists can even focus in on data for individual crops like corn, wheat and soybeans. They can look closely at regional crops, like citrus, that grow in only a few areas.
This nationwide view — provided by Landsat satellites orbiting 438 miles above Earth — is important to track the nation’s food supply. But with data from other satellites, like our ECOSTRESS instrument and ESA’s (the European Space Agency) Sentinel-2, agricultural scientists can monitor how healthy crops are in real time and predict when they’ll be ready to harvest.
In this false-color image of California farmland, red areas peak early in the season, whereas blue areas peak late. This information helps farmers watch over the plants in their fields, predict when they’ll be ready to harvest, and maximize crop production.
But while growing more and more crops sounds good, there can be challenges, like water. Especially when there’s not enough of it.
During California’s recent drought, just over 1 million acres of fertile farmland (shown in green) were fallow, or unused (red) in 2015. That’s nearly double the number of unused fields in 2011, the last year with normal rainfall before the drought.
Irrigating acres and acres of farmland takes lots of water. With remote sensing, scientists can track how irrigation fluctuates with climate change, new water management policies, or new technologies. Research like this helps farmers grow the most crops with the least amount of water.
As our climate changes, it’s more important than ever for farmers to have the knowledge they need to grow crops in a warming world. The data collected by our Earth-observing satellites help farmers learn about the planet that sustains us — and make better decisions about how to cultivate it.
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Rare & Record-Breaking Black Holes
While even the most “normal” black hole seems exotic compared to the tranquil objects in our solar system, there are some record-breaking oddballs. Tag along as we look at the biggest, closest, farthest, and even “spinniest” black holes discovered in the universe … that we know of right now!
Located 700 million light-years away in the galaxy Holmberg 15A, astronomers found a black hole that is a whopping 40 billion times the mass of the Sun — setting the record for the biggest black hole found so far. On the other hand, the smallest known black hole isn’t quite so easy to pinpoint. There are several black holes with masses around five times that of our Sun. There’s even one candidate with just two and a half times the Sun’s mass, but scientists aren’t sure whether it’s the smallest known black hole or actually the heaviest known neutron star!
You may need to take a seat for this one. The black hole GRS 1915+105 will make you dizzier than an afternoon at an amusement park, as it spins over 1,000 times per second! Maybe even more bizarre than how fast this black hole is spinning is what it means for a black hole to spin at all! What we're actually measuring is how strongly the black hole drags the space-time right outside its event horizon — the point where nothing can escape. Yikes!
If you’re from Earth, the closest black hole that we know of right now, Mon X-1 in the constellation Monoceros, is about 3,000 light-years away. But never fear — that’s still really far away! The farthest known black hole is J0313-1806. The light from its surroundings took a whopping 13 billion years to get to us! And with the universe constantly expanding, that distance continues to grow.
So, we know about large (supermassive, hundreds of thousands to billions of times the Sun's mass) and small (stellar-mass, five to dozens of times the Sun's mass) black holes, but what about other sizes? Though rare, astronomers have found a couple that seem to fit in between and call them intermediate-mass black holes. As for tiny ones, primordial black holes, there is a possibility that they were around when the universe got its start — but there’s not enough evidence so far to prove that they exist!
One thing that’s on astronomers’ wishlist is to see two supermassive black holes crashing into one another. Unfortunately, that event hasn’t been detected — yet! It could be only a matter of time before one reveals itself.
Though these are the records now, in early 2021 … records are meant to be broken, so who knows what we’ll find next!
Add some of these records and rare finds to your black hole-watch list, grab your handy-dandy black hole field guide to learn even more about them — and get to searching!
Keep up with NASA Universe on Facebook and Twitter where we post regularly about black holes.
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Top 5 Technologies Needed for a Spacecraft to Survive Deep Space
When a spacecraft built for humans ventures into deep space, it requires an array of features to keep it and a crew inside safe. Both distance and duration demand that spacecraft must have systems that can reliably operate far from home, be capable of keeping astronauts alive in case of emergencies and still be light enough that a rocket can launch it.
Missions near the Moon will start when the Orion spacecraft leaves Earth atop the world’s most powerful rocket, the Space Launch System. After launch from Kennedy Space Center in Florida, Orion will travel beyond the Moon to a distance more than 1,000 times farther than where the International Space Station flies in low-Earth orbit, and farther than any spacecraft built for humans has ever ventured. To accomplish this feat, Orion has built-in technologies that enable the crew and spacecraft to explore far into the solar system. Let’s check out the top five:
Systems to Live and Breathe
As humans travel farther from Earth for longer missions, the systems that keep them alive must be highly reliable while taking up minimal mass and volume. Orion will be equipped with advanced environmental control and life support systems designed for the demands of a deep space mission. A high-tech system already being tested aboard the space station will remove carbon dioxide (CO2) and humidity from inside Orion. The efficient system replaces many chemical canisters that would consume up to 10 percent of crew livable area. To save additional space, Orion will also have a new compact toilet, smaller than the one on the space station.
Highly reliable systems are critically important when distant crew will not have the benefit of frequent resupply shipments to bring spare parts from Earth. Even small systems have to function reliably to support life in space, from a working toilet to an automated fire suppression system or exercise equipment that helps astronauts stay in shape to counteract the zero-gravity environment. Distance from home also demands that Orion have spacesuits capable of keeping astronaut alive for six days in the event of cabin depressurization to support a long trip home.
Proper Propulsion
The farther into space a vehicle ventures, the more capable its propulsion systems need to be in order to maintain its course on the journey with precision and ensure its crew can get home.
Orion’s highly capable service module serves as the powerhouse for the spacecraft and provides propulsion capabilities that enable it to go around the Moon and back on exploration missions. The service module has 33 engines of various sizes. The main engine will provide major in-space maneuvering capabilities throughout the mission such as inserting Orion into lunar orbit and firing powerfully enough to exit orbit for a return trip to Earth. The other 32 engines are used to steer and control Orion on orbit.
In part due to its propulsion capabilities, including tanks that can hold nearly 2,000 gallons of propellant and a back up for the main engine in the event of a failure, Orion’s service module is equipped to handle the rigors of travel for missions that are both far and long. It has the ability to bring the crew home in a variety of emergency situations.
The Ability to Hold Off the Heat
Going to the Moon is no easy task, and it’s only half the journey. The farther a spacecraft travels in space, the more heat it will generate as it returns to Earth. Getting back safely requires technologies that can help a spacecraft endure speeds 30 times the speed of sound and heat twice as hot as molten lava or half as hot as the sun.
When Orion returns from the Moon it will be traveling nearly 25,000 mph, a speed that could cover the distance from Los Angeles to New York City in six minutes. Its advanced heat shield, made with a material called AVCOAT, is designed to wear away as it heats up. Orion’s heat shield is the largest of its kind ever built and will help the spacecraft withstand temperatures around 5,000 degrees Fahrenheit during reentry though Earth’s atmosphere.
Before reentry, Orion also will endure a 700-degree temperature range from about minus 150 to 550 degrees Fahrenheit. Orion’s highly capable thermal protection system, paired with thermal controls, will protect it during periods of direct sunlight and pitch black darkness while its crews comfortably enjoy a safe and stable interior temperature of about 77 degrees Fahrenheit.
Radiation Protection
As a spacecraft travels on missions beyond the protection of Earth’s magnetic field, it will be exposed to a harsher radiation environment than in low-Earth orbit with greater amounts of radiation from charged particles and solar storms. This kind of radiation can cause disruptions to critical computers, avionics and other equipment. Humans exposed to large amounts of radiation can experience both acute and chronic health problems ranging from near-term radiation sickness to the potential of developing cancer in the long-term.
Orion was designed from the start with built in system-level features to ensure reliability of essential elements of the spacecraft during potential radiation events. For example, Orion is equipped with four identical computers that each are self-checking, plus an entirely different backup computer, to ensure it can still send commands in the event of a disruption. Engineers have tested parts and systems to a high standard to ensure that all critical systems remain operable even under extreme circumstances.
Orion also has a makeshift storm shelter below the main deck of the crew module. In the event of a solar radiation event, we developed plans for crew on board to create a temporary shelter inside using materials on board. A variety of radiation sensors will also be on the spacecraft to help scientists better understand the radiation environment far away from Earth. One investigation, called AstroRad, will fly on Exploration Mission-1 and test an experimental vest that has the potential to help shield vital organs and decrease exposure from solar particle events.
Constant Communication and Navigation
Spacecraft venturing far from home go beyond the Global Positioning System (GPS) in space and above communication satellites in Earth orbit. To talk with mission control in Houston, Orion’s communication and navigation systems will switch from our Tracking and Data Relay Satellites (TDRS) system used by the International Space Station, and communicate through the Deep Space Network.
Orion is equipped with backup communication and navigation systems to help the spacecraft stay in contact with the ground and orient itself if its primary systems fail. The backup navigation system, a relatively new technology called optical navigation, uses a camera to take pictures of the Earth, Moon and stars and autonomously triangulate Orion’s position from the photos. Its backup emergency communications system doesn’t use the primary system or antennae for high-rate data transfer.
Keep up with all the latest news on our newest, state-of-the art spacecraft by following NASA Orion on Facebook and Twitter.
More on our Moon to Mars plans, here.
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All Eyes on Harvey
Our Earth-observing satellites, along with the cameras and crew of the International Space Station, are keeping a watchful eye over Hurricane Harvey as it churns in the Gulf of Mexico. When Hurricane Harvey blows ashore over coastal Texas on Friday night, it will likely be the first major hurricane to make landfall in the United States since 2005.
Above is a view of Harvey from NOAA's GOES-East satellite captured on Aug. 25 at 10:07 a.m. EDT (1407 UTC) clearly showing the storm’s eye as Harvey nears landfall in the southeastern coast of Texas. As Hurricane Harvey continued to strengthen, we analyzed the storm’s rainfall, cloud heights and cloud top temperatures.
Above, the Global Precipitation Mission (GPM) core observatory satellite flew almost directly above intensifying Hurricane Harvey on August 24, 2017 at 6:30 p.m. EDT (2230 UTC) and we used the Microwave Imager instrument to peer through dense storm clouds to reveal the location of intense rainfall bands near the center of the hurricane.
And from the International Space Station, cameras were pointed towards Harvey as the orbiting laboratory passed overhead 250 miles above the Earth. The video above includes views from the space station recorded on August 24, 2017 at 6:15 p.m. Eastern Time.
The National Hurricane Center expects Harvey to be a category 3 storm on the Saffir-Simpson scale—with winds higher than 111 miles (179 kilometers) per hour—when it makes landfall. It will likely produce a storm surge of 6 to 12 feet (2 to 4 meters) and drop between 15 and 25 inches (38 and 63 centimeters) of rain in some areas—enough to produce life-threatening flash floods.
For updated forecasts, visit the National Hurricane Center. Ensure you are prepared for Hurricanes. Get tips and more at FEMA’s Ready site. Get the latest updates from NASA satellites by visiting our Hurricane site.
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What’s a Blood Moon? And Other Lunar Eclipse Questions.
Tonight, Australians, Africans, Europeans, Asians and South Americans will have the opportunity to see the longest lunar eclipse of the century. Sorry North America.
Lunar eclipses occur about 2-4 times per year, when the Moon passes into the Earth’s shadow. In order to see a lunar eclipse, you must be on the night side of the Earth, facing the Moon, when the Earth passes in between the Moon and the Sun. Need help visualizing this? Here you go:
What’s the difference between a solar eclipse and a lunar eclipse?
An easy way to remember the difference between a solar eclipse and a lunar eclipse is that the word ‘eclipse’ refers to the object that is being obscured. During a solar eclipse, the Moon blocks the Sun from view. During a lunar eclipse, the Earth’s shadow obscures the Moon.
Why does the Moon turn red?
You may have heard the term ‘Blood Moon’ for a lunar eclipse. When the Moon passes into the Earth’s shadow, it turns red. This happens for the exact same reason that our sunrises and sunsets here on Earth are brilliant shades of pinks and oranges. During a lunar eclipse, the only light reaching the Moon passes through the Earth’s atmosphere. The bluer, shorter wavelength light scatters and the longer wavelength red light passes through and makes it to the Moon.
What science can we learn from a lunar eclipse?
"During a lunar eclipse, the temperature swing is so dramatic that it’s as if the surface of the Moon goes from being in an oven to being in a freezer in just a few hours,” said Noah Petro, project scientist for our Lunar Reconnaissance Orbiter, or LRO, at our Goddard Space Flight Center in Greenbelt, Maryland.
The Diviner team from LRO measures temperature changes on the Moon through their instrument on the spacecraft as well as through a thermal camera on Earth. How quickly or slowly the lunar surface loses heat helps scientists determine characteristics of lunar material, including its composition and physical properties.
When is the next lunar eclipse?
North Americans, don’t worry. If skies are clear, you can see the next lunar eclipse on January 21, 2019. The eclipse will be visible to North Americans, South Americans, and most of Africa and Europe.
To keep an eye on the Moon with us check out nasa.gov/moon or follow us on Twitter and Facebook.
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