As our planet warms, sea levels are rising around the world – and are doing so at an accelerating rate. Currently, global sea level is rising about an eighth of an inch every year.
That may seem insignificant, but it’s 30% more than when NASA launched its first satellite mission to measure ocean heights in 1992 – less than 30 years ago. And people already feel the impacts, as seemingly small increments of sea level rise become big problems along coastlines worldwide.
Higher global temperatures cause our seas to rise, but how? And why are seas rising at a faster and faster rate? There are two main reasons: melting ice and warming waters.
The Ice We See Is Getting Pretty Thin
About two-thirds of global sea level rise comes from melting glaciers and ice sheets, the vast expanses of ice that cover Antarctica and Greenland. In Greenland, most of that ice melt is caused by warmer air temperatures that melt the upper surface of ice sheets, and when giant chunks of ice crack off of the ends of glaciers, adding to the ocean.
In Antarctica – where temperatures stay low year-round – most of the ice loss happens at the edges of glaciers. Warmer ocean water and warmer air meet at the glaciers’ edges, eating away at the floating ice sheets there.
NASA can measure these changes from space. With data from the Ice, Cloud and land Elevation Satellite-2, or ICESat-2, scientists can measure the height of ice sheets to within a fraction of an inch. Since 2006, an average of 318 gigatons of ice per year has melted from Greenland and Antarctica’s ice sheets. To get a sense of how big that is: just one gigaton is enough to cover New York City’s Central Park in ice 1,000 feet deep – almost as tall as the Chrysler Building.
With the Gravity Recovery and Climate Experiment Follow-On (GRACE-FO) mission – a partnership with the German Research Centre for Geosciences – scientists can calculate the mass of ice lost from these vast expanses across Greenland and Antarctica.
It’s not just glaciers in Antarctica and Greenland that are melting, though. Nearly all glaciers have been melting in the last decade, including those in Alaska, High Mountain Asia, South America, and the Canadian Arctic. Because these smaller glaciers are melting quickly, they contribute about the same amount to sea level rise as meltwater from massive ice sheets.
The Water’s Getting Warm
As seawater warms, it takes up more space. When water molecules get warmer, the atoms in those molecules vibrate faster, expanding the volume they take up. This phenomenon is called thermal expansion. It’s an incredibly tiny change in the size of a single water molecule, but added across all the water molecules in all of Earth’s oceans – a single drop contains well over a billion billion molecules – it accounts for about a third of global sea level rise.
So Much to See
While sea level is rising globally, it’s not the same across the planet. Sea levels are rising about an eighth of an inch per year on average worldwide. But some areas may see triple that rate, some may not observe any changes, and some may even experience a drop in sea level. These differences are due to ocean currents, mixing, upwelling of cold water from the deep ocean, winds, movements of heat and freshwater, and Earth’s gravitational pull moving water around. When ice melts from Greenland, for example, the drop in mass decreases the gravitational pull from the ice sheet, causing water to slosh to the shores of South America.
That’s where our view from space comes in. We’re launching Sentinel-6 Michael Freilich, an international partnership satellite, to continue our decades-long record of global sea level rise.
We can agree that nebulae are some of the most majestic-looking objects in the universe. But what are they exactly? Nebulae are giant clouds of gas and dust in space. They’re commonly associated with two parts of the life cycle of stars: First, they can be nurseries forming new baby stars. Second, expanding clouds of gas and dust can mark where stars have died.
Not all nebulae are alike, and their different appearances tell us what's happening around them. Since not all nebulae emit light of their own, there are different ways that the clouds of gas and dust reveal themselves. Some nebulae scatter the light of stars hiding in or near them. These are called reflection nebulae and are a bit like seeing a street lamp illuminate the fog around it.
In another type, called emission nebulae, stars heat up the clouds of gas, whose chemicals respond by glowing in different colors. Think of it like a neon sign hanging in a shop window!
Finally there are nebulae with dust so thick that we’re unable to see the visible light from young stars shine through it. These are called dark nebulae.
Our missions help us see nebulae and identify the different elements that oftentimes light them up.
The Hubble Space Telescope is able to observe the cosmos in multiple wavelengths of light, ranging from ultraviolet, visible, and near-infrared. Hubble peered at the iconic Eagle Nebula in visible and infrared light, revealing these grand spires of dust and countless stars within and around them.
The Chandra X-ray Observatory studies the universe in X-ray light! The spacecraft is helping scientists see features within nebulae that might otherwise be hidden by gas and dust when viewed in longer wavelengths like visible and infrared light. In the Crab Nebula, Chandra sees high-energy X-rays from a pulsar (a type of rapidly spinning neutron star, which is the crushed, city-sized core of a star that exploded as a supernova).
The James Webb Space Telescope will primarily observe the infrared universe. With Webb, scientists will peer deep into clouds of dust and gas to study how stars and planetary systems form.
The Spitzer Space Telescope studied the cosmos for over 16 years before retiring in 2020. With the help of its detectors, Spitzer revealed unknown materials hiding in nebulae — like oddly-shaped molecules and soot-like materials, which were found in the California Nebula.
Studying nebulae helps scientists understand the life cycle of stars. Did you know our Sun got its start in a stellar nursery? Over 4.5 billion years ago, some gas and dust in a nebula clumped together due to gravity, and a baby Sun was born. The process to form a baby star itself can take a million years or more!
After billions more years, our Sun will eventually puff into a huge red giant star before leaving behind a beautiful planetary nebula (so-called because astronomers looking through early telescopes thought they resembled planets), along with a small, dense object called a white dwarf that will cool down very slowly. In fact, we don’t think the universe is old enough yet for any white dwarfs to have cooled down completely.
Since the Sun will live so much longer than us, scientists can't observe its whole life cycle directly ... but they can study tons of other stars and nebulae at different phases of their lives and draw conclusions about where our Sun came from and where it's headed. While studying nebulae, we’re seeing the past, present, and future of our Sun and trillions of others like it in the cosmos.
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why are cheetahs not technically big cats? is it just because they're weird as hell or do they not meet some big cat criteria?
so the thing about Big Cats is that they’re all closely related members of the genus Panthera!
because they’re all part of the same lineage, they share a lot of traits like the ability to roar.
and cheetahs are actually members of a completely different cat lineage altogether, the genus Acinonyx!
they’re not very closely related to the big cats at all and are actually most closely related to Pumas, which you can totally see if you stack them up next to each other and squint really hard.
it’s okay though, the cheetah can still be the biggest cat in our hearts :’)
Is there any chance that something could go wrong?
We. Are. Going 🌙
Today, we introduced the eighteen NASA Astronauts forming the Artemis team. Together, they’ll use their diverse range of backgrounds, expertise, and experience to pave the way for humans to return to the Moon, to stay.
Meet the heroes of the future who’ll carry us back to the Moon and beyond - the Artemis generation.
Fun fact: Joe is a veteran of the U.S. Peace Corps! Get to know Joe personally with this video –> Watch HERE.
Fun fact: Kayla got her start in public service through serving in the U.S. Navy. Get to know Kayla personally with this video –> Watch HERE.
Fun fact: Raja’s nickname is “Grinder,” and he comes from a test pilot background. Get to know Raja personally with this video –> Watch HERE.
Fun fact: Jessica is a rugby national champion winner and geologist. Get to know Jessica personally with this video –> Watch HERE.
Fun fact: Matthew sums himself up as a father, a husband and an explorer. Get to know Matthew personally with this video –> Watch HERE.
Fun fact: Jasmin says she still wakes up every morning and it feels like a “pinch me moment” to think she’s actually an astronaut right now. Get to know Jasmin personally with this video –> Watch HERE.
Fun fact: Victor’s dream is to work on the surface of the Moon. Get to know Victor personally with this video –> Watch HERE.
Fun fact: Jessica was five years old when she knew she wanted to be an astronaut. Get to know Jessica personally with this video –> Watch HERE.
Fun fact: Woody used to spend summers away from graduate school working search and rescue in Yosemite National Park. Get to know Woody personally with this video –> Watch HERE.
Fun fact: Anne is a West Point alumni who describes herself as an impractical dreamer. Get to know Anne personally with this video –> Watch HERE.
Fun fact: Jonny is also a U.S. Navy SEAL with a medical degree from Harvard. Get to know Jonny personally with this video –> Watch HERE.
Fun fact: Nicole is a U.S. Lieutenant Colonel in the Marine Corps! Get to know Nicole personally with this video –> Watch HERE.
Fun fact: Kjell was a flight surgeon, a physician who takes care of astronauts, before applying to be an astronaut himself! Get to know Kjell personally with this video –> Watch HERE.
Fun fact: Christina set a record for the longest single spaceflight by a woman with a total of 328 days in space. Get to know Christina personally with this video –> Watch HERE.
Fun fact: Frank was a Black Hawk helicopter pilot in the U.S. Army and family medical physician. Get to know Frank personally with this video –> Watch HERE.
Fun fact: Stephanie was the voice in Mission Control leading our NASA Astronauts for the all-woman spacewalk last year. Get to know Stephanie personally with this video –> Watch HERE.
Fun fact: Scott said he wanted to be an astronaut in a high school class and the students laughed – look at him now. Get to know Scott personally with this video –> Watch HERE.
Fun fact: Kate is actually IN space right now, so she will have to get her official portrait when she comes home! She is also the first person to sequence DNA in space. Get to know Kate personally with this video –> Watch HERE. Stay up to date with our Artemis program and return to the Moon by following NASA Artemis on Twitter, Facebook and Instagram.
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“If you read the history of the development of chemistry and particularly of physics, you will see that even such exact natural sciences could not, and still cannot, avoid basing their thought systems on certain hypotheses. In classical physics, up to the end of the 18th century, one of the working hypotheses, arrived at either unconsciously or half-consciously, was that space had three dimensions, an idea which was never questioned. The fact was always accepted, and perspective drawings of physical events, diagrams, or experiments, were always in accordance with that theory. Only when this theory is abandoned does one wonder how such a thing could ever have been believed. How did one come by such an idea? Why were we so caught that nobody ever doubted or even discussed the matter? It was accepted as a self-evident fact, but what was at the root of it? Johannes Kepler, one of the fathers of modern or classic physics, said that naturally space must have three dimensions because of the Trinity! So our readiness to believe that space has three dimensions is a more recent offspring of the Christian trinitarian idea.”
— Marie-Louise von Franz, Alchemy: An Introduction to the Symbolism and the Psychology
They say a picture is worth a thousand words, but no images have left a greater impact on our understanding of the universe quite like the Hubble Space Telescope’s deep fields. Like time machines, these iconic images transport humanity billions of light-years back in time, offering a glimpse into the early universe and insight into galaxy evolution!
You’ve probably seen these images before, but what exactly do we see within them? Deep field images are basically core samples of our universe. By peering into a small portion of the night sky, we embark on a journey through space and time as thousands of galaxies appear before our very eyes.
So, how can a telescope the size of a school bus orbiting 340 miles above Earth uncover these mind-boggling galactic masterpieces? We’re here to break it down. Here’s Hubble’s step-by-step guide to viewing deep fields:
Believe it or not, capturing the light of a thousand galaxies actually begins in the dark. To observe extremely faint galaxies in the farthest corners of the cosmos, we need minimal light interference from nearby stars and other celestial objects. The key is to point Hubble’s camera at a dark patch of sky, away from the outer-edge glow of our own galaxy and removed from the path of our planet, the Sun, or the Moon. This “empty” black canvas of space will eventually transform into a stunning cosmic mosaic of galaxies.
The first deep field image was captured in 1995. In order to see far beyond nearby galaxies, Hubble’s camera focused on a relatively empty patch of sky within the constellation Ursa Major. The results were this step-shaped image, an extraordinary display of nearly 3,000 galaxies spread across billions of light-years, featuring some of the earliest galaxies to emerge shortly after the big bang.
The universe is vast, and peering back billions of years takes time. Compared to Hubble’s typical exposure time of a few hours, deep fields can require hundreds of hours of exposure over several days. Patience is key. Capturing and combining several separate exposures allows astronomers to assemble a comprehensive core slice of our universe, providing key information about galaxy formation and evolution. Plus, by combining exposures from different wavelengths of light, astronomers are able to better understand galaxy distances, ages, and compositions.
The Hubble Ultra Deep Field is the deepest visible-light portrait of our universe. This astonishing display of nearly 10,000 galaxies was imaged over the course of 400 Hubble orbits around Earth, with a total of 800 exposures captured over 11.3 days.
The ability to see across billions of light-years and observe the farthest known galaxies in our universe requires access to wavelengths beyond those visible to the human eye. The universe is expanding and light from distant galaxies is stretched far across space, taking a long time to reach us here on Earth. This phenomenon, known as “redshift,” causes longer wavelengths of light to appear redder the farther they have to travel through space. Far enough away, and the wavelengths will be stretched into infrared light. This is where Hubble’s infrared vision comes in handy. Infrared light allows us to observe light from some of the earliest galaxies in our universe and better understand the history of galaxy formation over time.
In 2009, Hubble observed the Ultra Deep Field in the infrared. Using the Near Infrared Camera and Multi-Object Spectrometer, astronomers gathered one of the deepest core samples of our universe and captured some of the most distant galaxies ever observed.
Apart from their remarkable beauty and impressive imagery, deep field images are packed with information, offering astronomers a cosmic history lesson billions of years back in time within a single portrait. Since light from distant galaxies takes time to reach us, these images allow astronomers to travel through time and observe these galaxies as they appear at various stages in their development. By observing Hubble’s deep field images, we can begin to discover the questions we’ve yet to ask about our universe.
Credit: NASA, ESA, R. Bouwens and G. Illingworth (University of California, Santa Cruz)
Hubble’s deep field images observe galaxies that emerged as far back as the big bang. This image of the Hubble Ultra Deep Field showcases 28 of over 500 early galaxies from when the universe was less than one billion years old. The light from these galaxies represent different stages in their evolution as their light travels through space to reach us.
Hubble’s deep fields have opened a window to a small portion of our vast universe, and future space missions will take this deep field legacy even further. With advancements in technologies and scientific instruments, we will soon have the ability to further uncover the unimaginable.
Slated for launch in late 2021, NASA’s James Webb Space Telescope will offer a new lens to our universe with its impressive infrared capabilities. Relying largely on the telescope’s mid-infrared instrument, Webb will further study portions of the Hubble deep field images in greater detail, pushing the boundaries of the cosmic frontier even further.
And there you have it, Hubble’s guide to unlocking the secrets of the cosmos! To this day, deep field images remain fundamental building blocks for studying galaxy formation and deepening not only our understanding of the universe, but our place within it as well.
Still curious about Hubble Deep Fields? Explore more and follow along on Twitter, Facebook, and Instagram with #DeepFieldWeek!
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Tablets, smart appliances, and other technologies that are an indispensable part of daily life are no longer state-of-the-art compared to the research and technology development going on over our heads. As we celebrate 20 years of humans continuously living and working in space aboard the International Space Station, we’re recapping some of the out-of-this-world tech development and research being done on the orbiting lab too.
Our Space Technology Mission Directorate (STMD) helps redefine state-of-the-art tech for living and working in space. Here are 10 technologies tried and tested on the space station with helping hands from its astronaut occupants over the years.
Astronauts on the space station are responsible for everything from conducting science experiments and deploying satellites to tracking inventory and cleaning. While all are necessary, the crew can delegate some jobs to the newest robotic inhabitants – Astrobees.
These cube-shaped robots can work independently or in tandem, carrying out research activities. Once they prove themselves, the bots will take on some of the more time-consuming tasks, such as monitoring the status of dozens of experiments. The three robots – named Bumble, Honey, and Queen – can operate autonomously following a programmed set of instructions or controlled remotely. Each uses cameras for navigation, fans for propulsion, and a rechargeable battery for power. The robots also have a perching arm that lets them grip handrails or hold items. These free-flying helpers take advantage of another STMD technology called Gecko Grippers that “stick” to any surface.
We wanted to develop tools for grabbing space junk, and something strong and super-sticky is necessary to collect the diverse material orbiting Earth. So, engineers studied the gecko lizard, perhaps the most efficient “grabber” on this planet. Millions of extremely fine hairs on the bottom of their feet make an incredible amount of contact with surfaces so the gecko can hold onto anything. That inspired our engineers to create a similar material.
Now the Gecko Gripper made by OnRobot is sold on the commercial market, supporting industrial activities such as materials handling and assembly. The NASA gecko adhesive gripper that’s being tested in microgravity on the Astrobee robots was fabricated on Earth. But other small plastic parts can now be manufactured in space.
Frequent resupply trips from Earth to the Moon, Mars, and other solar system bodies are simply not realistic. In order to become truly Earth-independent and increase sustainability, we had to come up with ways to manufacture supplies on demand.
A demonstration of the first 3D printer in space was tested on the space station in 2014, proving it worked in microgravity. This paved the way for the first commercial 3D printer in space, which is operated by Made In Space. It has successfully produced more than 150 parts since its activation in 2016. Designs for tools, parts, and many other objects are transmitted to the station by the company, which also oversees the print jobs. Different kinds of plastic filaments use heat and pressure in a process that’s similar to the way a hot glue gun works. The molten material is precisely deposited using a back-and-forth motion until the part forms. The next logical step for efficient 3D printing was using recycled plastics to create needed objects.
To help fragile technology survive launch and keep food safe for consumption, NASA employs a lot of single-use plastics. That material is a valuable resource, so we are developing a number of ways to repurpose it. The Refabricator, delivered to the station in 2018, is designed to reuse everything from plastic bags to packing foam. The waste plastic is super-heated and transformed into the feedstock for its built-in 3D printer. The filament can be used repeatedly: a 3D-printed wrench that’s no longer needed can be dropped into the machine and used to make any one of the pre-programmed objects, such as a spoon. The dorm-fridge-sized machine created by Tethers Unlimited Inc. successfully manufactured its first object, but the technology experienced some issues in the bonding process likely due to microgravity’s effect on the materials. Thus, the Refabricator continues to undergo additional testing to perfect its performance.
An upcoming hardware test on the station will try out a new kind of 3D printer. The on-demand digital manufacturing technology is capable of using different kinds of materials, including plastic and metals, to create new parts. We commissioned TechShot Inc. to build the hardware to fabricate objects made from aerospace-grade metals and electronics. On Earth, FabLab has already demonstrated its ability to manufacture strong, complex metal tools and other items. The unit includes a metal additive manufacturing process, furnace, and endmill for post-processing. It also has built-in monitoring for in-process inspection. When the FabLab is installed on the space station, it will be remotely operated by controllers on Earth. Right now, another printer created by the same company is doing a different kind of 3D printing on station.
Today scientists are also learning to 3D print living tissues. However, the force of gravity on this planet makes it hard to print cells that maintain their shape. So on Earth, scientists use scaffolding to help keep the printed structures from collapsing.
The 3D BioFabrication Facility (BFF) created by TechShot Inc. could provide researchers a gamechanger that sidesteps the need to use scaffolds by bioprinting in microgravity. This first American bioprinter in space uses bio-inks that contain adult human cells along with a cell-culturing system to strengthen the tissue over time. Eventually, that means that these manufactured tissues will keep their shape once returned to Earth’s gravity! While the road to bioprinting human organs is likely still many years away, these efforts on the space station may move us closer to that much-needed capability for the more than 100,000 people on the wait list for organ transplant.
Conditions in space are hard on the human body, and they also can be punishing on food. Regular deliveries of food to the space station refresh the supply of nutritious meals for astronauts. But prepackaged food stored on the Moon or sent to Mars in advance of astronauts could lose some nutritional value over time.
That’s why the BioNutrients experiment is underway. Two different strains of baker’s yeast which are engineered to produce essential nutrients on demand are being checked for shelf life in orbit. Samples of the yeast are being stored at room temperature aboard the space station and then are activated at different intervals, frozen, and returned to Earth for evaluation. These tests will allow scientists to check how long their specially-engineered microbes can be stored on the shelf, while still supplying fresh nutrients that humans need to stay healthy in space. Such microbes must be able to be stored for months, even years, to support the longer durations of exploration missions. If successful, these space-adapted organisms could also be engineered for the potential production of medicines. Similar organisms used in this system could provide fresh foods like yogurt or kefir on demand. Although designed for space, this system also could help provide nutrition for people in remote areas of our planet.
Everything from paints and container seals to switches and thermal protection systems must withstand the punishing environment of space. Atomic oxygen, charged-particle radiation, collisions with meteoroids and space debris, and temperature extremes (all combined with the vacuum) are just some conditions that are only found in space. Not all of these can be replicated on Earth. In 2001, we addressed this testing problem with the Materials International Space Station Experiment (MISSE). Technologists can send small samples of just about any technology or material into low-Earth orbit for six months or more. Mounted to the exterior of the space station, MISSE has tested more than 4,000 materials. More sophisticated hardware developed over time now supports automatic monitoring that sends photos and data back to researchers on Earth. Renamed the MISSE Flight Facility, this permanent external platform is now owned and operated by the small business, Alpha Space Test & Research Alliance LLC. The woman-owned company is developing two similar platforms for testing materials and technologies on the lunar surface.
Small satellites could provide a cheaper, faster way to deliver small payloads to Earth from the space station. To do just that, the Technology Education Satellite, or TechEdSat, develops the essential technologies with a series of CubeSats built by college students in partnership with NASA. In 2017, TechEdSat-6 deployed from the station, equipped with a custom-built parachute called exo-brake to see if a controlled de-orbit was possible. After popping out of the back of the CubeSat, struts and flexible cords warped the parachute like a wing to control the direction in which it travelled. The exo-brake uses atmospheric drag to steer a small satellite toward a designated landing site. The most recent mission in the series, TechEdSat-10, was deployed from the station in July with an improved version of an exo-brake. The CubeSat is actively being navigated to the target entry point in the vicinity of the NASA’s Wallops Flight Facility on Wallops Island, Virginia.
Independent navigation for spacecraft in deep space is challenging because objects move rapidly and the distances between are measured in millions of miles, not the mere thousands of miles we’re used to on Earth. From a mission perched on the outside of the station, we were able to prove that X-rays from pulsars could be helpful. A number of spinning neutron stars consistently emit pulsating beams of X-rays, like the rotating beacon of a lighthouse. Because the rapid pulsations of light are extremely regular, they can provide the precise timing required to measure distances.
The Station Explorer for X-Ray Timing and Navigation (SEXTANT) demonstration conducted on the space station in 2017 successfully measured pulsar data and used navigation algorithms to locate the station as it moved in its orbit. The washing machine-sized hardware, which also produced new neutron star science via the Neutron star Interior Composition Explorer (NICER), can now be miniaturized to develop detectors and other hardware to make pulsar-based navigation available for use on future spacecraft.
As NASA continues to identify challenges and problems for upcoming deep space missions such as Artemis, human on Mars, and exploring distant moons such as Titan, STMD will continue to further technology development on the space station and Earth.
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