What's Up - December 2017

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.

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

Using All of Our Senses in Space

Today, we and the National Science Foundation (NSF) announced the detection of light and a high-energy cosmic particle that both came from near a black hole billions of trillions of miles from Earth. This discovery is a big step forward in the field of multimessenger astronomy.

But wait — what is multimessenger astronomy? And why is it a big deal?

People learn about different objects through their senses: sight, touch, taste, hearing and smell. Similarly, multimessenger astronomy allows us to study the same astronomical object or event through a variety of “messengers,” which include light of all wavelengths, cosmic ray particles, gravitational waves, and neutrinos — speedy tiny particles that weigh almost nothing and rarely interact with anything. By receiving and combining different pieces of information from these different messengers, we can learn much more about these objects and events than we would from just one.

Lights, Detector, Action!  

Much of what we know about the universe comes just from different wavelengths of light. We study the rotations of galaxies through radio waves and visible light, investigate the eating habits of black holes through X-rays and gamma rays, and peer into dusty star-forming regions through infrared light.

The Fermi Gamma-ray Space Telescope, which recently turned 10, studies the universe by detecting gamma rays — the highest-energy form of light. This allows us to investigate some of the most extreme objects in the universe.

Last fall, Fermi was involved in another multimessenger finding — the very first detection of light and gravitational waves from the same source, two merging neutron stars. In that instance, light and gravitational waves were the messengers that gave us a better understanding of the neutron stars and their explosive merger into a black hole.

Fermi has also advanced our understanding of blazars, which are galaxies with supermassive black holes at their centers. Black holes are famous for drawing material into them. But with blazars, some material near the black hole shoots outward in a pair of fast-moving jets. With blazars, one of those jets points directly at us!

Multimessenger Astronomy is Cool

Today’s announcement combines another pair of messengers. The IceCube Neutrino Observatory lies a mile under the ice in Antarctica and uses the ice itself to detect neutrinos. When IceCube caught a super-high-energy neutrino and traced its origin to a specific area of the sky, they alerted the astronomical community.

Fermi completes a scan of the entire sky about every three hours, monitoring thousands of blazars among all the bright gamma-ray sources it sees. For months it had observed a blazar producing more gamma rays than usual. Flaring is a common characteristic in blazars, so this did not attract special attention. But when the alert from IceCube came through about a neutrino coming from that same patch of sky, and the Fermi data were analyzed, this flare became a big deal!

IceCube, Fermi, and followup observations all link this neutrino to a blazar called TXS 0506+056. This event connects a neutrino to a supermassive black hole for the very first time.  

Why is this such a big deal? And why haven’t we done it before? Detecting a neutrino is hard since it doesn’t interact easily with matter and can travel unaffected great distances through the universe. Neutrinos are passing through you right now and you can’t even feel a thing!

The neat thing about this discovery — and multimessenger astronomy in general — is how much more we can learn by combining observations. This blazar/neutrino connection, for example, tells us that it was protons being accelerated by the blazar’s jet. Our study of blazars, neutrinos, and other objects and events in the universe will continue with many more exciting multimessenger discoveries to come in the future.

Want to know more? Read the story HERE.

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

Why are we studying them? What’s purpose of this field for us on earth?

How Will We Safely Send the First Humans to the Red Planet?

We’ve been exploring the Red Planet for over 50 years -- Mariner 4 launched on this day (Nov. 28) in 1964 and took the first photos of Mars from space the following summer.

We first explored the surface 40 years ago (Viking, 1976) and have had a continuous scientific presence on Mars for nearly 20 years, starting with the landing of the Pathfinder lander and Sojourner rover on July 4, 1997.

We currently have three orbiters – MAVEN, MRO and Mars Odyssey – and two rovers – Curiosity and Opportunity – actively exploring Mars.

These robotic explorers have already taught us a lot about the Red Planet, and future missions will teach us even more about how humans can live and work on the surface.

After sending humans on space exploration missions for the last 50 years, we have gained the experience and knowledge to send the first people to Mars. We are working across all areas to prepare for that historic day and want to share our progress with you. 

Building the ride to Mars: NASA’s Space Launch System.

Our ride to Mars, the Space Launch System, is being built right now to meet the challenges of exploring deep space. When it comes to our journey to Mars and beyond, there are no small steps. Our video series by the same name breaks down those steps to show how SLS will send missions to the Red Planet.

Living on the Space Station will help humans live safely on Mars.

New crew members of Expedition 50 will soon conduct more than 250 experiments on the International Space Station. More than 2,000 experiments have already been done! 

Experiments in fields such as biology, Earth science, physical sciences and human research are helping us unlock the knowledge needed to enable humans to live in space for long durations. If you missed the recent launch, check out NASA TV for a replay.

Testing Orion helps crew live and work in space and get home safely.

Scheduled to launch atop the Space Launch System rocket for the first time in 2018, an uncrewed Orion will travel farther into space than any spacecraft built for humans has ever gone before. When Orion returns to Earth, splashing down into the Pacific Ocean, it will take a landing and recovery group to safely return the capsule and crew back to land. A variety of testing on the ground, including to structures and parachutes, is helping make sure Orion can safely carry crew to new destinations in the solar system.

In late October, this recovery group, including NASA’s Ground Systems Development and Operations Program, the U.S. Navy, U.S. Air Force and contractor employees, completed its fifth successful practice run to recover Orion aboard the USS San Diego. 

We're using high resolution imagery from the Mars Reconnaissance Orbiter to learn more about potential landing sites for a human mission.

Who knows what surprises the Red Planet holds?

Our Curiosity Rover has discovered all kinds of interesting Mars features including meteorites. How do you learn more about a meteorite? Zap it with lasers, of course.

This golf-ball-sized, iron-nickel meteorite was recently found on Mars where ancient lakebed environments once existed. Named “Egg Rock” for the area in which it was found, it is the first meteorite to be examined using a laser-firing spectrometer.

By studying the conditions on Mars with vehicles like Curiosity, scientists are able to help prepare future astronauts to live on Mars.

How do you prepare the tallest rocket ever built for its first launch?

Another important component in successfully launching the Space Launch System rocket and Orion spacecraft on a Journey to Mars is the infrastructure work being done by our Ground Systems Development and Operations Program at Kennedy Space Center.

While efforts at our Vehicle Assembly Building continue, we hope you’ll be making your plans to join us at the launch pad for the first flight of SLS with Orion in 2018!

Preparing for a human journey to Mars

The next Mars rover will launch in 2020, and will investigate a region of Mars where the ancient environment may have been favorable for microbial life, probing the Martian rocks for evidence of past life. 

It will collect samples and cache them on the surface for potential return to Earth by a future mission. Mars 2020 will also conduct the first investigation into the usability and availability of Martian resources, including oxygen, in preparation for human missions.

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

Blowing Bubbles in the Gamma-ray Sky

Did you know our Milky Way galaxy is blowing bubbles? Two of them, each 25,000 light-years tall! They extend above and below the disk of the galaxy, like the two halves of an hourglass. We can’t see them with our own eyes because they’re only apparent in gamma-ray light, the highest-energy light in the universe.

We didn’t even know these humongous structures were smack in the middle of our galaxy until 2010. Scientists found them when they analyzed the first two years of data from NASA’s Fermi Gamma-ray Space Telescope. They dubbed them the “Fermi bubbles” and found that in addition to being really big and spread out, they seem to have well-defined edges. The bubbles’ shape and the light they give off led scientists to think they were created by a rapid release of energy. But by what? And when?

One possible explanation is that they could be leftovers from the last big meal eaten by the supermassive black hole at the center of our galaxy. This monster is more than 4 million times the mass of our own Sun. Scientists think it may have slurped up a big cloud of hydrogen between 6 and 9 million years ago and then burped jets of hot gas that we see in gamma rays and X-rays.

Another possible explanation is that the bubbles could be the remains of star formation. There are massive clusters of stars at very the center of the Milky Way — sometimes the stars are so closely packed they’re a million times more dense than in the outer suburb of the galaxy where we live. If there was a burst of star formation in this area a few million years ago, it could have created the surge of gas needed to in turn create the Fermi bubbles.

It took us until 2010 to see these Fermi bubbles because the sky is filled with a fog of other gamma rays that can obscure our view. This fog is created when particles moving near light speed bump into gas, dust, and light in the Milky Way. These collisions produce gamma rays, and scientists had to factor out the fog to unveil the bubbles.

Scientists continue to study the possible causes of these massive bubbles using the 10 years of data Fermi has collected so far. Fermi has also made many other exciting discoveries — like the the collision of superdense neutron stars and the nature of space-time. Learn more about Fermi and how we’ve been celebrating its first decade in space.

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

Vice President Mike Pence visited our Kennedy Space Center in Florida today. While there, he delivered remarks to the workforce and toured our complex to see progress toward sending humans deeper into space, and eventually to Mars. He also had the opportunity to see our work with commercial companies to launch humans from U.S. soil to the International Space Station. 

What was your fav sci-fi show/book/movie growing up?

I was a big fan of Doctor Who, and of course Star Trek!

What are Gravitational Waves?

Today, the National Science Foundation (NSF) announced the detection of gravitational waves by the Laser Interferometer Gravitational-Wave Observatory (LIGO), a pair of ground-based observatories. But...what are gravitational waves? Let us explain:

Gravitational waves are disturbances in space-time, the very fabric of the universe, that travel at the speed of light. The waves are emitted by any mass that is changing speed or direction. The simplest example is a binary system, where a pair of stars or compact objects (like black holes) orbit their common center of mass.

We can think of gravitational effects as curvatures in space-time. Earth’s gravity is constant and produces a static curve in space-time. A gravitational wave is a curvature that moves through space-time much like a water wave moves across the surface of a lake. It is generated only when masses are speeding up, slowing down or changing direction.

Did you know Earth also gives off gravitational waves? Earth orbits the sun, which means its direction is always changing, so it does generate gravitational waves, although extremely weak and faint.

What do we learn from these waves?

Observing gravitational waves would be a huge step forward in our understanding of the evolution of the universe, and how large-scale structures, like galaxies and galaxy clusters, are formed.

Gravitational waves can travel across the universe without being impeded by intervening dust and gas. These waves could also provide information about massive objects, such as black holes, that do not themselves emit light and would be undetectable with traditional telescopes.

Just as we need both ground-based and space-based optical telescopes, we need both kinds of gravitational wave observatories to study different wavelengths. Each type complements the other.

Ground-based: For optical telescopes, Earth’s atmosphere prevents some wavelengths from reaching the ground and distorts the light that does.

Space-based: Telescopes in space have a clear, steady view. That said, telescopes on the ground can be much larger than anything ever launched into space, so they can capture more light from faint objects.

How does this relate to Einstein’s theory of relativity?

The direct detection of gravitational waves is the last major prediction of Einstein’s theory to be proven. Direct detection of these waves will allow scientists to test specific predictions of the theory under conditions that have not been observed to date, such as in very strong gravitational fields.

In everyday language, “theory” means something different than it does to scientists. For scientists, the word refers to a system of ideas that explains observations and experimental results through independent general principles. Isaac Newton's theory of gravity has limitations we can measure by, say, long-term observations of the motion of the planet Mercury. Einstein's relativity theory explains these and other measurements. We recognize that Newton's theory is incomplete when we make sufficiently sensitive measurements. This is likely also true for relativity, and gravitational waves may help us understand where it becomes incomplete.

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

Juno Spacecraft: What Do We Hope to Learn?

The Juno spacecraft has been traveling toward its destination since its launch in 2011, and is set to insert Jupiter’s orbit on July 4. Jupiter is by far the largest planet in the solar system. Humans have been studying it for hundreds of years, yet still many basic questions about the gas world remain.

The primary goal of the Juno spacecraft is to reveal the story of the formation and evolution of the planet Jupiter. Understanding the origin and evolution of Jupiter can provide the knowledge needed to help us understand the origin of our solar system and planetary systems around other stars.

Have We Visited Jupiter Before? Yes! In 1995, our Galileo mission (artist illustration above) made the voyage to Jupiter. One of its jobs was to drop a probe into Jupiter’s atmosphere. The data showed us that the composition was different than scientists thought, indicating that our theories of planetary formation were wrong.

What’s Different About This Visit? The Juno spacecraft will, for the first time, see below Jupiter’s dense clover of clouds. [Bonus Fact: This is why the mission was named after the Roman goddess, who was Jupiter’s wife, and who could also see through the clouds.]

Unlocking Jupiter’s Secrets

Specifically, Juno will…

Determine how much water is in Jupiter’s atmosphere, which helps determine which planet formation theory is correct (or if new theories are needed)

Look deep into Jupiter’s atmosphere to measure composition, temperature, cloud motions and other properties

Map Jupiter’s magnetic and gravity fields, revealing the planet’s deep structure

Explore and study Jupiter’s magnetosphere near the planet’s poles, especially the auroras – Jupiter’s northern and southern lights – providing new insights about how the planet’s enormous

Juno will let us take a giant step forward in our understanding of how giant planets form and the role these titans played in putting together the rest of the solar system.

For updates on the Juno mission, follow the spacecraft on Facebook, Twitter, YouTube and Tumblr.

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

Thanks everyone for your fantastic questions! Sorry I couldn’t answer all of them. I hope you have fun on Monday, Aug. 21st and share your photos and experiences with us! https://www.flickr.com/groups/nasa-eclipse2017/ 

Safe viewing and talk to you later!  https://eclipse2017.nasa.gov/safety