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"I used to measure the heavens; now I shall measure the shadows of the earth. Although my soul was from heaven, the shadow of my body lies here."
-Johannes Kepler-
SHIELDS Up! NASA Rocket to Survey Our Solar System’s Windshield Apr 16, 2021
Eleven billion miles away – more than four times the distance from us to Pluto – lies the boundary of our solar system’s magnetic bubble, the heliopause. Here the Sun’s magnetic field, stretching through space like an invisible cobweb, fizzles to nothing. Interstellar space begins. “It’s really the largest boundary of its kind we can study,” said Walt Harris, space physicist at the University of Arizona in Tucson.
We still know little about what lies beyond this boundary. Fortunately, bits of interstellar space can come to us, passing right through this border and making their way into the solar system.
A new NASA mission will study light from interstellar particles that have drifted into our solar system to learn about the closest reaches of interstellar space. The mission, called the Spatial Heterodyne Interferometric Emission Line Dynamics Spectrometer, or SHIELDS, will have its first opportunity to launch aboard a suborbital rocket from the White Sands Missile Range in New Mexico on April 19, 2021.
Our entire solar system is adrift in a cluster of clouds, an area cleared by ancient supernova blasts. Astronomers call this region the Local Bubble, an oblong plot of space about 300 light-years long within the spiraling Orion arm of our Milky Way galaxy. It contains hundreds of stars, including our own Sun.
We fare this interstellar sea is our trusty vessel, the heliosphere, a much smaller (though still gigantic) magnetic bubble blown up by the Sun. As we orbit the Sun, the solar system itself, encased in the heliosphere, hurtles through the Local Bubble at about 52,000 miles per hour (23 kilometers per second). Interstellar particles pelt the nose of our heliosphere like rain against a windshield.
Our heliosphere is more like a rubber raft than a wooden sailboat: Its surroundings mold its shape. It compresses at points of pressure, expands where it gives way. Exactly how and where our heliosphere’s lining deforms gives us clues about the nature of the interstellar space outside it. This boundary – and any deformities in it – are what Walt Harris, principal investigator for the SHIELDS mission, is after.
SHIELDS is a telescope that will launch aboard a sounding rocket, a small vehicle that flies to space for a few minutes of observing time before falling back to Earth. Harris’ team launched an earlier iteration of the telescope as part of the HYPE mission in 2014, and after modifying the design, they’re ready to launch again.
SHIELDS will measure light from a special population of hydrogen atoms originally from interstellar space. These atoms are neutral, with a balanced number of protons and electrons. Neutral atoms can cross magnetic field lines, so they seep through the heliopause and into our solar system nearly unfazed – but not completely.
The small effects of this boundary crossing are key to SHIELDS’s technique. Charged particles flow around the heliopause, forming a barrier. Neutral particles from interstellar space must pass through this gauntlet, which alters their paths. SHIELDS was designed to reconstruct the trajectories of the neutral particles to determine where they came from and what they saw along the way.
A few minutes after launch, SHIELDS will reach its peak altitude of about 186 miles (300 kilometers) from the ground, far above the absorbing effect of Earth’s atmosphere. Pointing its telescope towards the nose of the heliosphere, it will detect light from arriving hydrogen atoms. Measuring how that light’s wavelength stretches or contracts reveals the particles’ speed. All told, SHIELDS will produce a map to reconstruct the shape and varying density of matter at the heliopause.
The data, Harris hopes, will help answer tantalizing questions about what interstellar space is like.
For instance, astronomers think the Local Bubble as a whole is about 1/10th as dense as most of the rest of the galaxy’s main disk. But we don’t know the details – for instance, is matter in the Local Bubble is distributed evenly, or bunched up in dense pockets surrounded by nothingness? “There’s a lot of uncertainty about the fine structure of the interstellar medium – our maps are kind of crude,” Harris said. “We know the general outlines of these clouds, but we don’t know what’s happening inside them.”
Astronomers also don’t know much about the galaxy’s magnetic field. But it should leave a mark on our heliosphere that SHIELDS can detect, compressing the heliopause in a specific way based on its strength and orientation.
Finally, learning what our current plot of interstellar space is like could be a helpful guide for the (distant) future. Our solar system is just passing through our current patch of space. In some 50,000 years, we’ll be on our way out of the Local Bubble and on to who knows what.
“We don’t really know what that other cloud is like, and we don’t know what happens when you cross a boundary into that cloud,” Harris said. “There’s a lot of interest in understanding what we’re likely to experience as our solar system makes that transition.”
Not that our solar system hasn’t done it before. Over the last four billion years, Harris explains, Earth has passed through a variety of interstellar environments. It’s just that now we’re around, with the scientific tools to document it.
“We’re just trying to understand our place in the galaxy, and where we’re headed in the future,” Harris said.
TOP IMAGE….An illustration of the heliosphere being pelted with cosmic rays from outside our solar system. Credit: NASA’s Goddard Space Flight Center/Conceptual Image Lab
LOWER IMAGE….Illustration of the Local Bubble. Credits: NASA’s Goddard Space Flight Center
Bill Nye said wear a fucking mask!!!
Would anybody want me to do lessons? Like if you send in an ask like 'Hey, what do you know abt *science topic*?' I could do some research and make it a post with links and videos? (Like my Gravitational Waves in the Space-Time Continuum post [link below, and pinned to my acct])
Would anybody send in asks???
Our Sun has an entourage of planets, moons, and smaller objects to keep it company as it traverses the galaxy. But it’s still lonely compared to many of the other stars out there, which often come in pairs. These cosmic couples, called binary stars, are very important in astronomy because they can easily reveal things that are much harder to learn from stars that are on their own. And some of them could even host habitable planets!
New stars emerge from swirling clouds of gas and dust that are peppered throughout the galaxy. Scientists still aren’t sure about all the details, but turbulence deep within these clouds may give rise to knots that are denser than their surroundings. The knots have stronger gravity, so they can pull in more material and the cloud may begin to collapse.
The material at the center heats up. Known as a protostar, it is this hot core that will one day become a star. Sometimes these spinning clouds of collapsing gas and dust may break up into two, three, or even more blobs that eventually become stars. That would explain why the majority of the stars in the Milky Way are born with at least one sibling.
We can’t always tell if we’re looking at binary stars using just our eyes. They’re often so close together in the sky that we see them as a single star. For example, Sirius, the brightest star we can see at night, is actually a binary system (see if you can spot both stars in the photo above). But no one knew that until the 1800s.
Precise observations showed that Sirius was swaying back and forth like it was at a middle school dance. In 1862, astronomer Alvan Graham Clark used a telescope to see that Sirius is actually two stars that orbit each other.
But even through our most powerful telescopes, some binary systems still masquerade as a single star. Fortunately there are a couple of tricks we can use to spot these pairs too.
Since binary stars orbit each other, there’s a chance that we’ll see some stars moving toward and away from us as they go around each other. We just need to have an edge-on view of their orbits. Astronomers can detect this movement because it changes the color of the star’s light – a phenomenon known as the Doppler effect.
Stars we can find this way are called spectroscopic binaries because we have to look at their spectra, which are basically charts or graphs that show the intensity of light being emitted over a range of energies. We can spot these star pairs because light travels in waves. When a star moves toward us, the waves of its light arrive closer together, which makes its light bluer. When a star moves away, the waves are lengthened, reddening its light.
Sometimes we can see binary stars when one of the stars moves in front of the other. Astronomers find these systems, called eclipsing binaries, by measuring the amount of light coming from stars over time. We receive less light than usual when the stars pass in front of each other, because the one in front will block some of the farther star’s light.
Twin stars don’t always get along with each other – their relationship may be explosive! Type Ia supernovae happen in some binary systems in which a white dwarf – the small, hot core left over when a Sun-like star runs out of fuel and ejects its outer layers – is stealing material away from its companion star. This results in a runaway reaction that ultimately detonates the thieving star. The same type of explosion may also happen when two white dwarfs spiral toward each other and collide. Yikes!
Scientists know how to determine how bright these explosions should truly be at their peak, making Type Ia supernovae so-called standard candles. That means astronomers can determine how far away they are by seeing how bright they look from Earth. The farther they are, the dimmer they appear. Astronomers can also look at the wavelengths of light coming from the supernovae to find out how fast the dying stars are moving away from us.
Studying these supernovae led to the discovery that the expansion of the universe is speeding up. Our Nancy Grace Roman Space Telescope will scan the skies for these exploding stars when it launches in the mid-2020s to help us figure out what’s causing the expansion to accelerate – a mystery known as dark energy.
Astronomers like finding binary systems because it’s a lot easier to learn more about stars that are in pairs than ones that are on their own. That’s because the stars affect each other in ways we can measure. For example, by paying attention to how the stars orbit each other, we can determine how massive they are. Since heavier stars burn hotter and use up their fuel more quickly than lighter ones, knowing a star’s mass reveals other interesting things too.
By studying how the light changes in eclipsing binaries when the stars cross in front of each other, we can learn even more! We can figure out their sizes, masses, how fast they’re each spinning, how hot they are, and even how far away they are. All of that helps us understand more about the universe.
Thanks to observatories such as our Kepler Space Telescope, we know that worlds like Luke Skywalker’s home planet Tatooine in “Star Wars” exist in real life. And if a planet orbits at the right distance from the two stars, it could even be habitable (and stay that way for a long time).
In 2019, our Transiting Exoplanet Survey Satellite (TESS) found a planet, known as TOI-1338 b, orbiting a pair of stars. These worlds are tricker to find than planets with only one host star, but TESS is expected to find several more!
Want to learn more about the relationships between stellar couples? Check out this Tumblr post: https://nasa.tumblr.com/post/190824389279/cosmic-couples-and-devastating-breakups
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Are you ready to see unprecedented, detailed views of the universe from the James Webb Space Telescope, the largest and most powerful space observatory ever made? Scroll down to see the first full-color images and data from Webb. Unfold the universe with us. ✨
This landscape of “mountains” and “valleys” speckled with glittering stars, called the Cosmic Cliffs, is the edge of the star-birthing Carina Nebula. Usually, the early phases of star formation are difficult to capture, but Webb can peer through cosmic dust—thanks to its extreme sensitivity, spatial resolution, and imaging capability. Protostellar jets clearly shoot out from some of these young stars in this new image.
The Southern Ring Nebula is a planetary nebula: it’s an expanding cloud of gas and dust surrounding a dying star. In this new image, the nebula’s second, dimmer star is brought into full view, as well as the gas and dust it’s throwing out around it. (The brighter star is in its own stage of stellar evolution and will probably eject its own planetary nebula in the future.) These kinds of details will help us better understand how stars evolve and transform their environments. Finally, you might notice points of light in the background. Those aren’t stars—they’re distant galaxies.
Stephan’s Quintet, a visual grouping of five galaxies near each other, was discovered in 1877 and is best known for being prominently featured in the holiday classic, “It’s a Wonderful Life.” This new image brings the galaxy group from the silver screen to your screen in an enormous mosaic that is Webb’s largest image to date. The mosaic covers about one-fifth of the Moon’s diameter; it contains over 150 million pixels and is constructed from almost 1,000 separate image files. Never-before-seen details are on display: sparkling clusters of millions of young stars, fresh star births, sweeping tails of gas, dust and stars, and huge shock waves paint a dramatic picture of galactic interactions.
WASP-96 b is a giant, mostly gas planet outside our solar system, discovered in 2014. Webb’s Near-Infrared Imager and Slitless Spectrograph (NIRISS) measured light from the WASP-96 system as the planet moved across the star. The light curve confirmed previous observations, but the transmission spectrum revealed new properties of the planet: an unambiguous signature of water, indications of haze, and evidence of clouds in the atmosphere. This discovery marks a giant leap forward in the quest to find potentially habitable planets beyond Earth.
This image of galaxy cluster SMACS 0723, known as Webb’s First Deep Field, looks 4.6 billion years into the past. Looking at infrared wavelengths beyond Hubble’s deepest fields, Webb’s sharp near-infrared view reveals thousands of galaxies—including the faintest objects ever observed in the infrared—in the most detailed view of the early universe to date. We can now see tiny, faint structures we’ve never seen before, like star clusters and diffuse features and soon, we’ll begin to learn more about the galaxies’ masses, ages, histories, and compositions.
These images and data are just the beginning of what the observatory will find. It will study every phase in the history of our Universe, ranging from the first luminous glows after the Big Bang, to the formation of solar systems capable of supporting life on planets like Earth, to the evolution of our own Solar System.
Make sure to follow us on Tumblr for your regular dose of space—and for milestones like this!
Credits: NASA, ESA, CSA, and STScI
Johannes Kepler was a German mathematician, astronomer, and astrologer.
Kepler is a key figure in the 17th-century scientific revolution. He is best known for his laws of planetary motion, based on his works Astronomia nova, Harmonices Mundi, and Epitome of Copernican Astronomy. These works also provided one of the foundations for Isaac Newton’s theory of universal gravitation.
In astronomy, Kepler’s laws of planetary motion are three scientific laws describing the motion of planets around the Sun.
The orbit of a planet is an ellipse with the Sun at one of the two foci.
A line segment joining a planet and the Sun sweeps out equal areas during equal intervals of time.
The square of the orbital period of a planet is proportional to the cube of the semi-major axis of its orbit.
Most planetary orbits are nearly circular, and careful observation and calculation are required in order to establish that they are not perfectly circular. Calculations of the orbit of Mars, whose published values are somewhat suspect, indicated an elliptical orbit. From this, Johannes Kepler inferred that other bodies in the Solar System, including those farther away from the Sun, also have elliptical orbits.
Kepler’s work (published between 1609 and 1619) improved the heliocentric theory of Nicolaus Copernicus, explaining how the planets’ speeds varied, and using elliptical orbits rather than circular orbits with epicycles.
Isaac Newton showed in 1687 that relationships like Kepler’s would apply in the Solar System to a good approximation, as a consequence of his own laws of motion and law of universal gravitation.
Johannes Kepler
Kepler’s laws of planetary motion
Did you know we help farmers grow some of your favorite fruits, veggies and grains?
Our Earth-observing satellites track rainfall amounts, soil moisture, crop health, and more. On the ground, we partner with agencies and organizations around the world to help farmers use that data to care for their fields.
Here are a few ways we help put food on the table, from planting to harvest.
Did you plant seeds in science class to watch them sprout and grow? They all needed water, right? Our data helps farmers “see” how moist the soil is across large fields.
“When you’re not sure when to water your flowers or your garden, you can look at the soil or touch it with your hands. We are sort of ‘feeling’ the soil, sensing how much water is in the soil – from a satellite,
685 kilometers (408 miles) above Earth,” said John Bolten, the associate program manager of water resources for NASA’s Applied Sciences Program.
This spring, we worked with the U.S. Department of Agriculture and George Mason University to release Crop-CASMA, a tool that shows soil moisture and vegetation conditions for the United States. Able to see smaller areas – about the size of a couple of golf courses – the USDA uses Crop-CASMA to help update farmers on their state’s soil moisture, crop health and growing progress.
It’s dangerous being a seedling.
Heavy spring rains or summer storms can flood fields and drown growing plants. Dry spells and droughts can starve them of nutrients. Insects and hail can damage them. Farmers need to keep a close eye on plants during the spring and summer months. Our data and programs help them do that.
For example, in California, irrigation is essential for agriculture. California’s Central Valley annually produces more than 250 types of crops and is one of the most productive agricultural regions in the country – but it’s dry. Some parts only get 6 inches of rain per year.
To help, Landsat data powers CropManage – an app that tells farmers how long to irrigate their fields, based on soil conditions and evapotranspiration, or how much water plants are releasing into the atmosphere. The warmer and drier the atmosphere, the more plants “sweat” and lose water that needs to be replenished. Knowing how long to irrigate helps farmers conserve water and be more efficient. In years like 2021, intense droughts can make water management especially critical.
Harvest
Leading up to harvest, farmers need to know their expected yields – and profits.
GEOGLAM, or the Group on Earth Observations Global Agricultural Monitoring Initiative, is a partnership between NASA Harvest, USDA’s Foreign Agricultural Service (FAS) and other global agencies to track and report on crop conditions around the world.
USDA FAS is one of the main users of a soil moisture measurement product developed by Bolten and his team at our NASA Goddard Space Flight Center to drive their crop forecasting system.
If you’re interested in more ways we support agriculture, stay tuned over the next few weeks to learn more about how satellites (and scientists) help put snacks on your table!
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NASA astronauts Shannon Walker, Victor Glover, and Mike Hopkins, and JAXA (Japan Aerospace Exploration Agency) astronaut Soichi Noguchi embark on a historic mission on November 14, 2020 aboard the Crew Dragon. NASA’s Crew-1 mission marks the first certified crew rotation flight to the International Space Station. During their 6-month stay on orbit, these crew members will don their science caps and complete experiments in microgravity. Check out five out of this world experiments you can expect to see these space scientists working on during Expedition 64.
The Crew-1 astronauts will become space farmers with the responsibility of tending to the rad(ish) garden located in a facility known as the Advanced Plant Habitat (APH). Researchers are investigating radishes in the Plant Habitat-02 experiment as a candidate crop for spaceflight applications to supplement food sources for astronauts. Radishes have the benefits of high nutritional content and quick growth rates, making these veggies an intriguing option for future space farmers on longer missions to the Moon or Mars.
Microbes can seemingly do it all, including digging up the dirt (so to speak). The BioAsteroid investigation looks at the ability of bacteria to break down rock. Future space explorers could use this process for extracting elements from planetary surfaces and refining regolith, the type of soil found on the moon, into usable compounds. To sum it up, these microbial miners rock.
The iconic spacesuits used to walk on the moon and perform spacewalks on orbit are getting an upgrade. The next generation spacesuit, the Exploration Extravehicular Mobility Unit (xEMU), will be even cooler than before, both in looks and in terms of ability to regulate astronaut body temperature. The Spacesuit Evaporation Rejection Flight Experiment (SERFE) experiment is a technology demonstration being performed on station to look at the efficiency of multiple components in the xEMU responsible for thermal regulation, evaporation processes, and preventing corrosion of the spacesuits.
Crew-1 can expect to get a delivery of many types of chips during their mission. We aren’t referring to the chips you would find in your pantry. Rather, Tissue Chips in Space is an initiative sponsored by the National Institutes of Health to study 3D organ-like constructs on a small, compact devices in microgravity. Organ on a chip technology allows for the study of disease processes and potential therapeutics in a rapid manner. During Expedition 64, investigations utilizing organ on a chip technology will include studies on muscle loss, lung function, and the blood brain barrier – all on devices the size of a USB flashdrive.
Circadian rhythm, otherwise known as our “internal clock,” dictates our sleep-wake cycles and influences cognition. Fruit flies are hitching a ride to the space station as the subjects of the Genes in Space-7 experiment, created by a team of high school students. These flies, more formally known as the Drosophila melanogaster, are a model organism, meaning that they are common subjects of scientific study. Understanding changes in the genetic material that influences circadian rhythm in microgravity can shed light on processes relevant to an astronaut’s brain function.
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