Solar System: 2015 Year In Review

Top Study Tips from NASA

Study smarter this school year! We asked scientists, engineers, astronauts, and experts from across NASA about their favorite study tips – and they delivered. Here are a few of our favorites:

Study with friends

Find friends that are like-minded and work together to understand the material better. Trading ideas with a friend on how to tackle a problem can help you both strengthen your understanding.

Create a study environment

Find a quiet space or put on headphones so you can focus. You might not be able to get to the International Space Station yet, but a library, a study room, or a spot outside can be a good place to study. If it’s noisy around you, try using headphones to block out distractions.

Take breaks

Don’t burn yourself out! Take a break, go for a walk, get some water, and come back to it.

Looking for more study tips? Check out this video for all ten tips to start your school year off on the right foot!

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Black Holes: Seeing the Invisible!

Black holes are some of the most bizarre and fascinating objects in the cosmos. Astronomers want to study lots of them, but there’s one big problem – black holes are invisible! Since they don’t emit any light, it’s pretty tough to find them lurking in the inky void of space. Fortunately there are a few different ways we can “see” black holes indirectly by watching how they affect their surroundings.

Speedy stars

If you’ve spent some time stargazing, you know what a calm, peaceful place our universe can be. But did you know that a monster is hiding right in the heart of our Milky Way galaxy? Astronomers noticed stars zipping superfast around something we can’t see at the center of the galaxy, about 10 million miles per hour! The stars must be circling a supermassive black hole. No other object would have strong enough gravity to keep them from flying off into space.

Two astrophysicists won half of the Nobel Prize in Physics last year for revealing this dark secret. The black hole is truly monstrous, weighing about four million times as much as our Sun! And it seems our home galaxy is no exception – our Hubble Space Telescope has revealed that the hubs of most galaxies contain supermassive black holes.

Shadowy silhouettes

Technology has advanced enough that we’ve been able to spot one of these supermassive black holes in a nearby galaxy. In 2019, astronomers took the first-ever picture of a black hole in a galaxy called M87, which is about 55 million light-years away. They used an international network of radio telescopes called the Event Horizon Telescope.

In the image, we can see some light from hot gas surrounding a dark shape. While we still can’t see the black hole itself, we can see the “shadow” it casts on the bright backdrop.

Shattered stars

Black holes can come in a smaller variety, too. When a massive star runs out of the fuel it uses to shine, it collapses in on itself. These lightweight or “stellar-mass” black holes are only about 5-20 times as massive as the Sun. They’re scattered throughout the galaxy in the same places where we find stars, since that’s how they began their lives. Some of them started out with a companion star, and so far that’s been our best clue to find them.

Some black holes steal material from their companion star. As the material falls onto the black hole, it gets superhot and lights up in X-rays. The first confirmed black hole astronomers discovered, called Cygnus X-1, was found this way.

If a star comes too close to a supermassive black hole, the effect is even more dramatic! Instead of just siphoning material from the star like a smaller black hole would do, a supermassive black hole will completely tear the star apart into a stream of gas. This is called a tidal disruption event.

Making waves

But what if two companion stars both turn into black holes? They may eventually collide with each other to form a larger black hole, sending ripples through space-time – the fabric of the cosmos!

These ripples, called gravitational waves, travel across space at the speed of light. The waves that reach us are extremely weak because space-time is really stiff.

Three scientists received the 2017 Nobel Prize in Physics for using LIGO to observe gravitational waves that were sent out from colliding stellar-mass black holes. Though gravitational waves are hard to detect, they offer a way to find black holes without having to see any light.

We’re teaming up with the European Space Agency for a mission called LISA, which stands for Laser Interferometer Space Antenna. When it launches in the 2030s, it will detect gravitational waves from merging supermassive black holes – a likely sign of colliding galaxies!

Rogue black holes

So we have a few ways to find black holes by seeing stuff that’s close to them. But astronomers think there could be 100 million black holes roaming the galaxy solo. Fortunately, our Nancy Grace Roman Space Telescope will provide a way to “see” these isolated black holes, too.

Roman will find solitary black holes when they pass in front of more distant stars from our vantage point. The black hole’s gravity will warp the starlight in ways that reveal its presence. In some cases we can figure out a black hole’s mass and distance this way, and even estimate how fast it’s moving through the galaxy.

For more about black holes, check out these Tumblr posts!

⚫ Gobble Up These Black (Hole) Friday Deals!

⚫ Hubble’s 5 Weirdest Black Hole Discoveries

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Boo! Did we get you? 🎃

This solar jack-o-lantern, captured by our Solar Dynamics Observatory (SDO) in October 2014, gets its ghoulish grin from active regions on the Sun, which emit more light and energy than the surrounding dark areas. Active regions are markers of an intense and complex set of magnetic fields hovering in the sun’s atmosphere.

The SDO has kept an unblinking eye on the Sun since 2010, recording phenomena like solar flares and coronal loops. It measures the Sun’s interior, atmosphere, magnetic field, and energy output, helping us understand our nearest star.

Grab the high-resolution version here.

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Rockets, Racecars, and the Physics of Going Fast

When our Space Launch System (SLS) rocket launches the Artemis missions to the Moon, it can have a top speed of more than six miles per second. Rockets and racecars are designed with speed in mind to accomplish their missions—but there’s more to speed than just engines and fuel. Learn more about the physics of going fast:

Take a look under the hood, so to speak, of our SLS mega Moon rocket and you’ll find that each of its four RS-25 engines have high-pressure turbopumps that generate a combined 94,400 horsepower per engine. All that horsepower creates more than 2 million pounds of thrust to help launch our four Artemis astronauts inside the Orion spacecraft beyond Earth orbit and onward to the Moon. How does that horsepower compare to a racecar? World champion racecars can generate more than 1,000 horsepower as they speed around the track.

As these vehicles start their engines, a series of special machinery is moving and grooving inside those engines. Turbo engines in racecars work at up to 15,000 rotations per minute, aka rpm. The turbopumps on the RS-25 engines rotate at a staggering 37,000 rpm. SLS’s RS-25 engines will burn for approximately eight minutes, while racecar engines generally run for 1 ½-3 hours during a race.

To use that power effectively, both rockets and racecars are designed to slice through the air as efficiently as possible.

While rockets want to eliminate as much drag as possible, racecars carefully use the air they’re slicing through to keep them pinned to the track and speed around corners faster. This phenomenon is called downforce.

Steering these mighty machines is a delicate process that involves complex mechanics.

Most racecars use a rack-and-pinion system to convert the turn of a steering wheel to precisely point the front tires in the right direction. While SLS doesn’t have a steering wheel, its powerful engines and solid rocket boosters do have nozzles that gimbal, or move, to better direct the force of the thrust during launch and flight.

Racecar drivers and astronauts are laser focused, keeping their sights set on the destination. Pit crews and launch control teams both analyze data from numerous sensors and computers to guide them to the finish line. In the case of our mighty SLS rocket, its 212-foot-tall core stage has nearly 1,000 sensors to help fly, track, and guide the rocket on the right trajectory and at the right speed. That same data is relayed to launch teams on the ground in real time. Like SLS, world-champion racecars use hundreds of sensors to help drivers and teams manage the race and perform at peak levels.

Knowing how to best use, manage, and battle the physics of going fast, is critical in that final lap. You can learn more about rockets and racecars here.

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Everyone (Even You!) Can Use Satellite Data

At NASA we’re pretty great at putting satellites and science instruments into orbit around Earth. But it turns out we’re also pretty great at showing people how to get and use all that data.

One of the top ways you can learn how to use NASA data is our ARSET program. ARSET is our Applied Remote Sensing Training program and it helps people build skills that integrate all these Earth science data into their decision making.

ARSET will train you on how to use data from a variety of Earth-observing satellites and instruments aboard the International Space Station.

Once you take a training, you’ll be in GREAT company because thousands of people have taken an ARSET training.

We hold in person and online trainings to people around the world, showing them how to use NASA Earth science data. Trainings are offered in air quality, climate, disaster, health, land, water resources and wildfire management.

For example, if you’re trying to track how much fresh drinking water there is in your watershed, you can take an ARSET training and learn how to find satellite data on how much precipitation has fallen over a certain time period or even things like the ‘moistness’ of soil and the quality of the water.

Best yet, all NASA Earth observing data is open and freely available to the whole world! That’s likely one of the reasons we’ve had participants from 172 of the approximately 190 countries on Earth.

Since its beginning 10 years ago, ARSET has trained more than 30 thousand people all over the world. They’ve also worked with people from more than 7,500 different organizations and that includes government agencies, non-profit groups, advocacy organizations, private industry.

And even though 2019 is ARSET’s 10th birthday – we’ve only just begun. Every year about 60% of the organizations and agencies we train are new to the program. We’re training just about anyone who is anyone doing Earth science on Earth! 

Join us, learn more about how we train people to use Earth observing data here, and heck, you can even take a training yourself: https://arset.gsfc.nasa.gov/.

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May the Four Forces Be With You!

May the force be with you? Much to learn you still have, padawan. In our universe it would be more appropriate to say, “May the four forces be with you.”

There are four fundamental forces that bind our universe and its building blocks together. Two of them are easy to spot — gravity keeps your feet on the ground while electromagnetism keeps your devices running. The other two are a little harder to see directly in everyday life, but without them, our universe would look a lot different!

Let’s explore these forces in a little more detail.

Gravity: Bringing the universe together

If you jump up, gravity brings you back down to Earth. It also keeps the solar system together … and our galaxy, and our local group of galaxies and our supercluster of galaxies.

Gravity pulls everything together. Everything, from the bright centers of the universe to the planets farthest from them. In fact, you (yes, you!) even exert a gravitational force on a galaxy far, far away. A tiny gravitational force, but a force nonetheless.

Credit: NASA and the Advanced Visualization Laboratory at the National Center for Supercomputing and B. O'Shea, M. Norman

Despite its well-known reputation, gravity is actually the weakest of the four forces. Its strength increases with the mass of the two objects involved. And its range is infinite, but the strength drops off as the square of the distance. If you and a friend measured your gravitational tug on each other and then doubled the distance between you, your new gravitational attraction would just be a quarter of what it was. So, you have to be really close together, or really big, or both, to exert a lot of gravity.

Even so, because its range is infinite, gravity is responsible for the formation of the largest structures in our universe! Planetary systems, galaxies and clusters of galaxies all formed because gravity brought them together.

Gravity truly surrounds us and binds us together.

Electromagnetism: Lighting the way

You know that shock you get on a dry day after shuffling across the carpet? The electricity that powers your television? The light that illuminates your room on a dark night? Those are all the work of electromagnetism. As the name implies, electromagnetism is the force that includes both electricity and magnetism.

Electromagnetism keeps electrons orbiting the nucleus at the center of atoms and allows chemical compounds to form (you know, the stuff that makes up us and everything around us). Electromagnetic waves are also known as light. Once started, an electromagnetic wave will travel at the speed of light until it interacts with something (like your eye) — so it will be there to light up the dark places.

Like gravity, electromagnetism works at infinite distances. And, also like gravity, the electromagnetic force between two objects falls as the square of their distance. However, unlike gravity, electromagnetism doesn't just attract. Whether it attracts or repels depends on the electric charge of the objects involved. Two negative charges or two positive charges repel each other; one of each, and they attract each other. Plus. Minus. A balance.

This is what happens with common household magnets. If you hold them with the same “poles” together, they resist each other. On the other hand, if you hold a magnet with opposite poles together — snap! — they’ll attract each other.

Electromagnetism might just explain the relationship between a certain scruffy-looking nerf-herder and a princess.

Strong Force: Building the building blocks

Credit: Lawrence Livermore National Laboratory

The strong force is where things get really small. So small, that you can’t see it at work directly. But don’t let your eyes deceive you. Despite acting only on short distances, the strong force holds together the building blocks of the atoms, which are, in turn, the building blocks of everything we see around us.

Like gravity, the strong force always attracts, but that’s really where their similarities end. As the name implies, the force is strong with the strong force. It is the strongest of the four forces. It brings together protons and neutrons to form the nucleus of atoms — it has to be stronger than electromagnetism to do it, since all those protons are positively charged. But not only that, the strong force holds together the quarks — even tinier particles — to form those very protons and neutrons.

However, the strong force only works on very, very, very small distances. How small? About the scale of a medium-sized atom’s nucleus. For those of you who like the numbers, that’s about 10-15 meters, or 0.000000000000001 meters. That’s about a hundred billion times smaller than the width of a human hair! Whew.

Its tiny scale is why you don’t directly see the strong force in your day-to-day life. Judge a force by its physical size, do you? 

Weak Force: Keeping us in sunshine

If you thought it was hard to see the strong force, the weak force works on even smaller scales — 1,000 times smaller. But it, too, is extremely important for life as we know it. In fact, the weak force plays a key role in keeping our Sun shining.

But what does the weak force do? Well … that requires getting a little into the weeds of particle physics. Here goes nothing! We mentioned quarks earlier — these are tiny particles that, among other things, make up protons and neutrons. There are six types of quarks, but the two that make up protons and neutrons are called up and down quarks. The weak force changes one quark type into another. This causes neutrons to decay into protons (or the other way around) while releasing electrons and ghostly particles called neutrinos.

So for example, the weak force can turn a down quark in a neutron into an up quark, which will turn that neutron into a proton. If that neutron is in an atom’s nucleus, the electric charge of the nucleus changes. That tiny change turns the atom into a different element! Such reactions are happening all the time in our Sun, giving it the energy to shine.

The weak force might just help to keep you in the (sun)light.

All four of these forces run strong in the universe. They flow between all things and keep our universe in balance. Without them, we’d be doomed. But these forces will be with you. Always.

You can learn more about gravity from NASA’s Space Place and follow NASAUniverse on Twitter or Facebook to learn about some of the cool cosmic objects we study with light.

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Questions coming up from….

@maybeinanotherworld: JWST IS HAPPENING! How are all of you feeling about this?

@Anonymous: How powerful is this telescope, exactly?

@Anonymous: Why are the mirrors on it yellow?

@foeofcolor: How long is this estimated to last for? Like how long will it be able to function in space by estimates?

All Eyes on the Sky for the August 21 Total Solar Eclipse

Just two months from now, the moon will completely block the sun’s face, treating part of the US to a total solar eclipse.

Everyone in North America will have the chance to see an eclipse of some kind if skies are clear. Anyone within a 70-mile-wide swath of land — called the path of totality — that stretches from Oregon to South Carolina will have the chance to see a total eclipse.

Throughout the rest of the continent, including all 50 United States — and even in parts of South America, Africa, Europe, and Asia — the moon will partially obscure the sun, creating a partial eclipse.

Photo credit: NASA/Cruikshank

An eclipse is one of nature’s most awesome sights, but safety comes first! When any part of the sun’s surface is exposed, use proper eclipse glasses (not sunglasses) or an indirect viewing method, like a pinhole projector. In the path of totality, it’s safe to look directly at the eclipse ONLY during the brief moments of totality.

During a solar eclipse, the moon passes between the sun and Earth, casting a shadow down on Earth’s surface. We’ve been studying the moon with NASA’s Lunar Reconnaissance Orbiter, and its precise mapping helped NASA build the most accurate eclipse map to date.

During a total solar eclipse, the moon blocks out the sun’s bright face, revealing the otherwise hidden solar atmosphere, called the corona. The corona is one of the sun’s most interesting regions — key to understanding the root of space weather events that shape Earth’s space environment, and mysteries such as why the sun’s atmosphere is so much hotter than its surface far below.

This is the first time in nearly 100 years that a solar eclipse has crossed the United States from coast to coast. We’re taking advantage of this long eclipse path by collecting data that’s not usually accessible — including studying the solar corona, testing new corona-observing instruments, and tracking how our planet’s atmosphere, plants, and animals respond to the sudden loss of light and heat from the sun.

We’ll be studying the eclipse from the ground, from airplanes, with research balloons, and of course, from space.

Three of our sun-watchers — the Solar Dynamics Observatory, IRIS, and Hinode, a joint mission led by JAXA — will see a partial eclipse from space. Several of our Earth-observing satellites will use the eclipse to study Earth under uncommon conditions. For example, both Terra and DSCOVR, a joint mission led by NOAA, will capture images of the moon’s shadow from space. Our Lunar Reconnaissance Orbiter will also turn its instruments to face Earth and attempt to track the moon’s shadow as it moves across the planet.

There’s just two months to go until August 21, so make your plans now for the big day! No matter where you are, you can follow the eclipse as it crosses the country with live footage from NASA TV.

Learn more about the upcoming total solar eclipse — including where, when, and how to safely experience it — at eclipse2017.nasa.gov and follow along on Twitter @NASASun.  

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Hello! I have always wondered about how the clouds work, it seems like they are just gas in the air, but what makes them appear so often? Or how do they form? And how and why do the block out the sun if they're just air?

7 Things to Know About Spacewalks

On Wednesday, Oct. 28 and Friday, Nov. 6, Commander Scott Kelly and Flight Engineer Kjell Lindgren will perform spacewalks in support of space station assembly and maintenance. You can watch both of these events live on NASA Television. But, before you do, here are 7 things to know:

1. What’s the Point of a Spacewalk?

Spacewalks are important events where crew members repair, maintain and upgrade parts of the International Space Station. Spacewalks can also be referred to as an EVA – Extravehicular Activity. On Wednesday, Oct. 28, Commander Scott Kelly and Flight Engineer Kjell Lindgren will complete a spacewalk. During this time they will service the Canadarm2 robotic arm, route cables for a future docking port, and place a thermal cover over a dark matter detection experiment, which is a state-of-the-art particles physics detector that has been attached to the station since 2011.

2. What Do They Wear?

The Extravehicular Mobility Unit (EMU) spacewalking suit weighs around 350 pounds. It’s weightless in space, but mass is still very real. The EMU provides a crew member with life support and an enclosure that enables them to work outside the space station. The suit provides atmospheric containment, thermal insulation, cooling, solar radiation protection and micrometeoroid/orbital debris protection.

3. How Long Are Spacewalks?

Spacewalks typically last around 6 1/2 hours, but can be extended to 7 or 8 hours, if necessary. The timeline is designed to accommodate as many tasks as possible, as spacewalks require an enormous amount of work to prepare.

4. What About Eating and Drinking?

Before a spacewalk astronauts eat light, usually something like a protein bar. The spacesuits also have a drink bag inside, and there is a bite valve that allows ready access to water.

5. What About Communication?

Spacewalkers wear a ‘comm’ cap that allows them to constantly communicate with astronauts inside the space station that are helping with the walk, and with mission control. Astronauts also wear a checklist on their left wrist called a “cuff checklist”. This list contains emergency procedures.

6. What About Light?

Something that most people don’t realize about spacewalks is that the crew will experience a sunrise/sunset every 45 minutes. Luckily, their spacesuits are equipped with lights that allow them to see in times of darkness.

7. How Do They Stay Safe?

When on a spacewalk, astronauts use safety tethers to stay close to their spacecraft. One end of the tether is hooked to the spacewalker, while the other end is connected to the vehicle. Another way astronauts stay safe is by wearing a SAFER, which is a Simplified Aid for EVA Rescue. This device is worn like a backpack and uses small jet thrusters to let an astronaut move around in space.

You can watch both of the upcoming spacewalks live on: NASA Television or the NASA App, or follow along on @Space_Station Twitter.

Wednesday, Oct. 28: Coverage begins at 6:30 a.m. EDT. Spacewalk begins at 8:10 a.m.

Friday, Nov. 6: Coverage begins at 5:45 a.m. EDT. Spacewalk begins at 7:15 a.m.

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