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Earth Facts that Live Rent-Free in Our Heads

Earth is a big weird planet. With so much going on, it’s easy to forget some of the many, many processes happening here. But at the same time, some stuff is so unexpected and just plain strange that it’s impossible to forget. We asked around and found out lots of people here at NASA have this problem.

Here are some facts about Earth that live rent free in our heads:

Earth has a solid inner core that is almost as hot as the surface of the Sun. Earth’s core gets as high as 9,800 degrees Fahrenheit, while the surface of the Sun is about 10,000 degrees Fahrenheit.

Dust from the Sahara fertilizes the Amazon rainforest. 27.7 million tons blow all the way across the Atlantic Ocean to the rainforest each year, where it brings phosphorus – a nutrient plants need to grow.

Ice in Antarctica looks solid and still, but it’s actually flowing – in some places it flows so fast that scientific instruments can move as much as a kilometer (more than half a mile!) a year.

Speaking of Antarctica: Ice shelves (the floating part of ice sheets) can be as big as Texas. Because they float, they rise and fall with the tide. So floating ice as big as Texas, attached to the Antarctic Ice Sheet, can rise and fall up to ~26 feet!

Melting ice on land makes its way to the ocean. As polar glaciers melt, the water sloshes to the equator, and which can actually slow the spin of Earth.

Even though it looks it, the ocean isn’t level. The surface has peaks and valleys and varies due to changes in height of the land below, winds, temperature, saltiness, atmospheric pressure, ocean circulation, and more.

Earth isn’t the only mind-blowing place out there. From here, we look out into the rest of the universe, full of weird planets and galaxies that surprise us.

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NASA’s View of COVID-19

#COVID19 led to changes in human activities around the globe. We can see some of these changes from space. Some bodies of water have run clearer, emissions of pollutants have temporarily declined, and transportation and shipment of goods have decreased.

Along with our partner agencies – ESA and JAXA – we’re making satellite data available on the COVID-19 Earth Observation Dashboard, where you can explore some of the changes we can see from space.

But it’s not just what we can see. When the pandemic began, NASA engineers sprang into action to build ventilators, oxygen hoods and more to help save lives.

Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com

Spread your cosmic wings 🦋

The Butterfly Nebula, created by a dying star, was captured by the Hubble Space Telescope in this spectacular image. Observations were taken over a more complete spectrum of light, helping researchers better understand the “wings'' of gas bursting out from its center. The nebula’s dying central star has become exceptionally hot, shining ultraviolet light brightly over the butterfly’s wings and causing the gas to glow.

Learn more about Hubble’s celebration of Nebula November and see new nebula images, here.

You can also keep up with Hubble on Twitter, Instagram, Facebook, and Flickr!

Image credits: NASA, ESA, and J. Kastner (RIT)

Cosmic Alphabet Soup: Classifying Stars

If you’ve spent much time stargazing, you may have noticed that while most stars look white, some are reddish or bluish. Their colors are more than just pretty – they tell us how hot the stars are. Studying their light in greater detail can tell us even more about what they’re like, including whether they have planets. Two women, Williamina Fleming and Annie Jump Cannon, created the system for classifying stars that we use today, and we’re building on their work to map out the universe.

By splitting starlight into spectra – detailed color patterns that often feature lots of dark lines – using a prism, astronomers can figure out a star’s temperature, how long it will burn, how massive it is, and even how big its habitable zone is. Our Sun’s spectrum looks like this:

Astronomers use spectra to categorize stars. Starting at the hottest and most massive, the star classes are O, B, A, F, G (like our Sun), K, M. Sounds like cosmic alphabet soup! But the letters aren’t just random – they largely stem from the work of two famous female astronomers.

Williamina Fleming, who worked as one of the famous “human computers” at the Harvard College Observatory starting in 1879, came up with a way to classify stars into 17 different types (categorized alphabetically A-Q) based on how strong the dark lines in their spectra were. She eventually classified more than 10,000 stars and discovered hundreds of cosmic objects!

That was back before they knew what caused the dark lines in spectra. Soon astronomers discovered that they’re linked to a star’s temperature. Using this newfound knowledge, Annie Jump Cannon – one of Fleming’s protégés – rearranged and simplified stellar classification to include just seven categories (O, B, A, F, G, K, M), ordered from highest to lowest temperature. She also classified more than 350,000 stars!

Type O stars are both the hottest and most massive in the new classification system. These giants can be a thousand times bigger than the Sun! Their lifespans are also around 1,000 times shorter than our Sun’s. They burn through their fuel so fast that they only live for around 10 million years. That’s part of the reason they only make up a tiny fraction of all the stars in the galaxy – they don’t stick around for very long.

As we move down the list from O to M, stars become progressively smaller, cooler, redder, and more common. Their habitable zones also shrink because the stars aren’t putting out as much energy. The plus side is that the tiniest stars can live for a really long time – around 100 billion years – because they burn through their fuel so slowly.

Astronomers can also learn about exoplanets – worlds that orbit other stars – by studying starlight. When a planet crosses in front of its host star, different kinds of molecules in the planet’s atmosphere absorb certain wavelengths of light.

By spreading the star’s light into a spectrum, astronomers can see which wavelengths have been absorbed to determine the exoplanet atmosphere’s chemical makeup. Our James Webb Space Telescope will use this method to try to find and study atmospheres around Earth-sized exoplanets – something that has never been done before.

Our upcoming Nancy Grace Roman Space Telescope will study the spectra from entire galaxies to build a 3D map of the cosmos. As light travels through our expanding universe, it stretches and its spectral lines shift toward longer, redder wavelengths. The longer light travels before reaching us, the redder it becomes. Roman will be able to see so far back that we could glimpse some of the first stars and galaxies that ever formed.

Learn more about how Roman will study the cosmos in our other posts:

Roman’s Family Portrait of Millions of Galaxies

New Rose-Colored Glasses for Roman

How Gravity Warps Light

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We judge ourselves by what we feel capable of doing, while others judge us by what we have already done.

Henry Wadsworth Longfellow (via quotemadness)

We Just Found Water on the Moon’s Sunlit Surface

When the first Apollo astronauts returned from the Moon in 1969, the Moon’s surface was thought to be completely dry. Over the last 20 years, orbital and impactor missions confirmed water ice is present inside dark, permanently shadowed craters around the poles. But could water survive in the Moon’s sunnier regions? Using SOFIA, the world’s largest flying observatory, we found water on a sunlit lunar surface for the first time. The discovery suggests water may be distributed across the Moon’s surface, which is a whopping 14.6 million square miles. Scientists think the water could be stored inside glass beadlike structures within the soil that can be smaller than the tip of a pencil. The amount of water detected is equivalent to about a 12-ounce bottle trapped in a cubic meter volume of soil. While that amount is 100 times less than what’s found in the Sahara Desert, discovering even small amounts raises new questions about how this precious resource is created and persists on the harsh, airless lunar surface. Learn more about the discovery: 

Water was found in Clavius Crater, one of the Moon’s largest craters visible from Earth.

The water may be delivered by tiny meteorite impacts… 

…or formed by the interaction of energetic particles ejected from the Sun. 

Follow-up observations by SOFIA will look for water in additional sunlit locations on the Moon.

We are eager to learn all we can about the presence of water in advance of sending the first woman and next man to the lunar surface in 2024 under our Artemis program. What we learn on and around the Moon will help us take the next giant leap – sending astronauts to Mars.

Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com