人生を、いかに楽しむか ということも、 また『試練』のひとつなのだ。

Roman's primary structure hangs from cables as it moves into the big clean room at NASA's Goddard Space Flight Center.

What Makes the Clean Room So Clean?

When you picture NASA’s most important creations, you probably think of a satellite, telescope, or maybe a rover. But what about the room they’re made in? Believe it or not, the room itself where these instruments are put together—a clean room—is pretty special. 

A clean room is a space that protects technology from contamination. This is especially important when sending very sensitive items into space that even small particles could interfere with.

There are two main categories of contamination that we have to keep away from our instruments. The first is particulate contamination, like dust. The second is molecular contamination, which is more like oil or grease. Both types affect a telescope’s image quality, as well as the time it takes to capture imagery. Having too many particles on our instruments is like looking through a dirty window. A clean room makes for clean science!

Two technicians clean the floor of Goddard’s big clean room.

Our Goddard Space Flight Center in Greenbelt, Maryland has the largest clean room of its kind in the world. It’s as tall as an eight-story building and as wide as two basketball courts.

Goddard’s clean room has fewer than 3,000 micron-size particles per cubic meter of air. If you lined up all those tiny particles, they’d be no longer than a sesame seed. If those particles were the size of 16-inch (0.4-meter) inflatable beach balls, we’d find only 3,000 spread throughout the whole body of Mount Everest!

A clean room technician observes a sample under a microscope.

The clean room keeps out particles larger than five microns across, just seven percent of the width of an average human hair. It does this via special filters that remove around 99.97% of particles 0.3 microns and larger from incoming air. Six fans the size of school buses spin to keep air flowing and pressurize the room. Since the pressure inside is higher, the clean air keeps unclean air out when doors open.

A technician analyzes a sample under ultraviolet light.

In addition, anyone who enters must wear a “bunny suit” to keep their body particles away from the machinery. A bunny suit covers most of the person inside. Sometimes scientists have trouble recognizing each other while in the suits, but they do get to know each other’s mannerisms very well.

This illustration depicts the anatomy of a bunny suit, which covers clean room technicians from head to toe to protect sensitive technology.

The bunny suit is only the beginning: before putting it on, team members undergo a preparation routine involving a hairnet and an air shower. Fun fact – you’re not allowed to wear products like perfume, lotion, or deodorant. Even odors can transfer easily!

Six of Goddard’s clean room technicians (left to right: Daniel DaCosta, Jill Bender, Anne Martino, Leon Bailey, Frank D’Annunzio, and Josh Thomas).

It takes a lot of specialists to run Goddard’s clean room. There are 10 people on the Contamination Control Technician Team, 30 people on the Clean Room Engineering Team to cover all Goddard missions, and another 10 people on the Facilities Team to monitor the clean room itself. They check on its temperature, humidity, and particle counts.

A technician rinses critical hardware with isopropyl alcohol and separates the particulate and isopropyl alcohol to leave the particles on a membrane for microscopic analysis.

Besides the standard mopping and vacuuming, the team uses tools such as isopropyl alcohol, acetone, wipes, swabs, white light, and ultraviolet light. Plus, they have a particle monitor that uses a laser to measure air particle count and size.

The team keeping the clean room spotless plays an integral role in the success of NASA’s missions. So, the next time you have to clean your bedroom, consider yourself lucky that the stakes aren’t so high!

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How the Sun Affects Asteroids in Our Neighborhood

It’s no secret the Sun affects us here on Earth in countless ways, from causing sunburns to helping our houseplants thrive. The Sun affects other objects in space, too, like asteroids! It can keep them in place. It can move them. And it can even shape them.

Asteroids embody the story of our solar system’s beginning. Jupiter’s Trojan asteroids, which orbit the Sun on the same path as the gas giant, are no exception. The Trojans are thought to be left over from the objects that eventually formed our planets, and studying them might offer clues about how the solar system came to be.

Over the next 12 years, NASA’s Lucy mission will visit eight asteroids—including seven Trojans— to help answer big questions about planet formation and the origins of our solar system. It will take the spacecraft about 3.5 years to reach its first destination.

How does the Sun affect what Lucy might find?

Place in Space

Credits: Astronomical Institute of CAS/Petr Scheirich

The Sun makes up 99.8% of the solar system’s mass and exerts a strong gravitational force as a result. In the case of the Trojan asteroids that Lucy will visit, their very location in space is dictated in part by the Sun’s gravity. They are clustered at two Lagrange points. These are locations where the gravitational forces of two massive objects—in this case the Sun and Jupiter—are balanced in such a way that smaller objects (like asteroids or satellites) stay put relative to the larger bodies. The Trojans lead and follow Jupiter in its orbit by 60° at Lagrange points L4 and L5.

Pushing Asteroids Around (with Light!)

The Sun can move and spin asteroids with light! Like many objects in space, asteroids rotate. At any given moment, the Sun-facing side of an asteroid absorbs sunlight while the dark side sheds energy as heat. When the heat escapes, it creates an infinitesimal amount of thrust, pushing the asteroid ever so slightly and altering its rotational rate. The Trojans are farther from the Sun than other asteroids we’ve studied before, and it remains to be seen how sunlight affects their movement.

Cracking the Surface (Also with Light!)

The Sun can break asteroids, too. Rocks expand as they warm and contract when they cool. This repeated fluctuation can cause them to crack. The phenomenon is more intense for objects without atmospheres, such as asteroids, where temperatures vary wildly. Therefore, even though the Trojans are farther from the Sun than rocks on Earth, they’ll likely show more signs of thermal fracturing.

Solar Wind-Swept

Like everything in our solar system, asteroids are battered by the solar wind, a steady stream of particles, magnetic fields, and radiation that flows from the Sun. For the most part, Earth’s magnetic field protects us from this bombardment. Without magnetic fields or atmospheres of their own, asteroids receive the brunt of the solar wind. When incoming particles strike an asteroid, they can kick some material off into space, changing the fundamental chemistry of what’s left behind.

Follow along with Lucy’s journey with NASA Solar System on Instagram, Facebook, and Twitter, and be sure to tune in for the launch at 5 a.m. EDT (09:00 UTC) on Saturday, Oct. 16 at nasa.gov/live.

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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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“There are some people who could hear you speak a thousand words, and still not understand you. And there are others who will understand. without you even speaking a word.”

— Yasmin Mogahed

Hot New Planetary System Just Dropped.

We hope you like your planetary systems extra spicy. 🔥

A new system of seven sizzling planets has been discovered using data from our retired Kepler space telescope.

Named Kepler-385, it’s part of a new catalog of planet candidates and multi-planet systems discovered using Kepler.

The discovery helps illustrate that multi-planetary systems have more circular orbits around the host star than systems with only one or two planets.

Our Kepler mission is responsible for the discovery of the most known exoplanets to date. The space telescope’s observations ended in 2018, but its data continues to paint a more detailed picture of our galaxy today.

Here are a few more things to know about Kepler-385:

All seven planets are between the size of Earth and Neptune.

Its star is 10% larger and 5% hotter than our Sun.

This system is one of over 700 that Kepler’s data has revealed.

The planets’ orbits have been represented in sound.

Now that you’ve heard a little about this planetary system, get acquainted with more exoplanets and why we want to explore them.

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Black Holes Dine on Stellar Treats!

See that tiny blob of light, circled in red? Doesn’t look like much, does it? But that blob represents a feast big enough to feed a black hole around 30 million times the mass of our Sun! Scientists call these kinds of stellar meals tidal disruption events, and they’re some of the most dramatic happenings in the cosmos.

Sometimes, an unlucky star strays too close to a black hole. The black hole’s gravity pulls on the star, causing it to stretch in one direction and squeeze in another. Then the star pulls apart into a stream of gas. This is a tidal disruption event. (If you’re worried about this happening to our Sun – don’t. The nearest black hole we know about is over 1,000 light-years away. And black holes aren’t wild space vacuums. They don’t go zipping around sucking up random stars and planets. So we’re pretty safe from tidal disruption events!)

The trailing part of the stream gets flung out of the system. The rest of the gas loops back around the black hole, forming a disk. The material circling in the disk slowly drifts inward toward the black hole’s event horizon, the point at which nothing – not even light – can escape. The black hole consumes the gas and dust in its disk over many years.

Sometimes the black hole only munches on a passing star – we call this a partial tidal disruption event. The star loses some of its gas, but its own gravity pulls it back into shape before it passes the black hole again. Eventually, the black hole will have nibbled away enough material that the star can’t reform and gets destroyed.

We study tidal disruptions, both the full feasts and the partial snacks, using many kinds of telescopes. Usually, these events are spotted by ground-based telescopes like the Zwicky Transient Facility and the All-Sky Automated Survey for Supernovae network.

They alert other ground- and space-based telescopes – like our Neil Gehrels Swift Observatory (illustrated above) and the European Space Agency’s XMM-Newton – to follow up and collect more data using different wavelengths, from visible light to X-rays. Even our planet-hunting Transiting Exoplanet Survey Satellite has observed a few of these destructive wonders!

We’re also studying disruptions using multimessenger astronomy, where scientists use the information carried by light, particles, and space-time ripples to learn more about cosmic objects and occurrences.

But tidal disruptions are super rare. They only happen once every 10,000 to 100,000 years in a galaxy the size of our own Milky Way. Astronomers have only observed a few dozen events so far. By comparison, supernovae – the explosive deaths of stars – happen every 100 years or so in a galaxy like ours.

That’s why scientists make their own tidal disruptions using supercomputers, like the ones shown in the video here. Supercomputers allow researchers to build realistic models of stars. They can also include all of the physical effects they’d experience whipping ‘round a black hole, even those from Einstein’s theory of general relativity. They can alter features like how close the stars get and how massive the black holes are to see how it affects what happens to the stars. These simulations will help astronomers build better pictures of the events they observe in the night sky.

Keep up with what’s happening in the universe and how we study it by following NASA Universe on Twitter and Facebook.

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