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Page 1234
Click for high-resolution animation
1. Light Beyond the Bulb: Bent Light in Space
QuicktimeMPEG One of the most interesting characteristics of light is that the path that it travels can bend. This happens when light is moving through one medium like air, and then enters another medium like glass or water. We experience this all of the time here on Earth. Whenever we put eyeglasses on or insert contact lenses, we are taking advantage of the fact that we can bend the path of light so it can properly focus onto the retinas of our eyes. We also see examples of bent light in the slightly oval appearance of the setting Sun or when we think we see water on in the distance on a hot highway.

Light being bent is also very important when we want to learn about things in space. In fact, some of the most exciting discoveries made by the Chandra X-ray Observatory and other telescopes involve light that has been bent. Take, for example, the Bullet Cluster. This system contains two galaxy clusters that have rammed into one another at tremendous speeds. The collision was so violent that normal matter has been wrenched away from dark matter. While we can't see the dark matter directly, we can learn where it is by light being lensed.

How does this work? When the light from very distant galaxies passes through a massive cluster of galaxies, like in the Bullet Cluster, the cluster can bend the path of the galaxy's light, in essence acting like a lens. From the vantage point of our telescopes, the distant galaxies appear distorted or elongated. Astronomers can use this information to build maps about where the dark matter is, which tells them more about this mysterious substance.

The ultimate light benders in the Universe are black holes, which can bend light rays into a closed loop so they never escape the black hole. Chandra has observed many black holes and their environments over the course of the mission. Whether they are the smaller black holes that are produced by the collapse of a giant star or the enormous supermassive black holes at the centers of galaxies, Chandra will continue to observe these objects that bend light in amazing ways across the Universe.

[Runtime: 03:40]
(NASA/CXC/A. Hobart)

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2. Chandra Sketches: Highlights of Light
QuicktimeMPEG Light comes in different forms. The light that we see with our eyes is just a fraction of all light. Light also encompasses wavelengths ranging from radio waves to gamma rays.

Nothing in the Universe can travel faster than light. In a vacuum, light travels at over 300,000 kilometers (186,000 miles) per second. This means light could circle the Earth 7.5 times in one second.

As light travels, its path can be bent when it goes from one medium to another (such as air to water). It can also be blocked (when a shadow occurs, for example), reflected (as with a mirror), or absorbed (like when a stone is heated by infrared light (waves) from the Sun.)

Humans have learned how to harness light and employ it in technologies ranging from medical devices (MRI/laser) to cell phones to giant telescopes.
[Runtime: 02:23]
(NASA/CXC/A. Hobart)

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3. Chandra Sketches: Our Connection With Light
QuicktimeMPEG We rely on light - both natural and artificial - to brighten and power our world, but also for so much more.

We use light-based medical tools to help understand and defeat disease.

We use light to advance manufacturing, which helps drive the global economy and move us toward sustainable practices.

We use light to monitor our climate and forecast the weather.

We use light from the cosmos to understand distant galaxies, to look for signs of life out there, and to learn more about our own planet.

Whether it comes from the Sun, a distant galaxy or a neon sign around the corner, light is all around us. We use it to communicate, navigate, learn and explore.
[Runtime: 02:14]
(NASA/CXC/A. Hobart)

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4. Light Beyond the Bulb: Over and Beyond the Rainbow
QuicktimeMPEG For the millions of years that humans and our ancestors have roamed this planet, we have been familiar with light. While scientists and philosophers have tried to figure out exactly what light is for millennia, it's only been in the past several hundred years or so that we've really started to figure it out.

In 1665, Isaac Newton, then a young scientist at Cambridge University in England, took a glass prism and held it up to a beam of sunlight streaming through the window. He saw the sunlight that passed through the prism spread out into the colors of the rainbow - red, orange, yellow, green, blue and violet. This was a crucial step in beginning to understand some of the properties of light.

Of course, we know today that Newton was experimenting with what we call "visible light." In 1800, William Herschel made a huge step in revealing that there was light outside what humans could see with their eyes with the discovery of infrared light. The prefix "infra" means "below" and "beyond," which makes sense as this type of light falls just outside the red color of visible light. Soon thereafter, Johann Ritter discovered light on the other end of the visible light spectrum and named it "ultraviolet."

The latter half of the 19th century and the early 20th century saw a rapid explosion of discoveries in the field of light, including identifying X-rays, and gamma rays. Important theoretical work by such scientists as James Clerk Maxwell and Albert Einstein helped piece together all of these discoveries and better understand what light is and how it behaves.

Today, light in all its forms is used for countless applications. A vivid example of different types of light being used together is in modern astronomy. While visible light telescopes have been around since Galileo's time in the early 1600's, the last century has seen the development of telescopes in virtually every wavelength known. Telescopes such as NASA's Chandra X-ray Observatory could not be developed until rocket technology advanced far enough because the Earth's atmosphere blocks X-rays from space from reaching our planet's surface. Other types of light, including certain bands of infrared, ultraviolet, and gamma rays, are in the same situation. We are lucky to be in an era where astronomers can combine data from across the electromagnetic spectrum - from both telescopes on the ground and those in space. It's just one of the many ways that light helps us explore and learn about the world we live in and the Universe that surrounds us.
[Runtime: 03:59]
(NASA/CXC/A. Hobart)

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5. Light Beyond the Bulb: Intro to Light
QuicktimeMPEG The year 2015 has been declared to be the International Year of Light and Light-based Technologies by the United Nations. People around the world are using this year-long celebration, nicknamed IYL 2015, to look at all of the amazing things light can do.

Whether it comes from the Sun, a distant galaxy, or a neon sign around the corner, light is all around us. We use light to communicate, navigate, learn, explore, and much more.

Light comes in many forms. In fact, the light that we see with our eyes, the same light that makes up the colors of the rainbow,

Light is fascinating for many reasons, including the fact that it possesses qualities of both a wave and a particle. We often characterize light and its behavior based on how far apart the crests of its waves are. This is called wavelength. Alternately, light can be viewed as being composed of a stream of particles.

Another aspect of light that is so amazing is how fast it travels. Nothing in the Universe can travel faster than light. In a vacuum, light moves at an astonishing 1.08 billion kilometers per hour. In other units, this translates into 671 million miles per hour. To put this in perspective, this means light could circle around the Earth seven and a half times in just one second.

In upcoming episodes, we will look at different aspects of light. We will explore some of its intriguing properties and how humans have greatly benefited from learning all that we can about light, which goes far beyond the bulb.
[Runtime: 03:24]
(NASA/CXC/A. Hobart)

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6. Chandra Sketches: Chandra Explained
QuicktimeMPEG NASA's Chandra X-ray Observatory was launched into space aboard the space shuttle in 1999. Chandra goes around the Earth in an elliptical orbit. This orbit takes Chandra about a third of the way to the moon.

Chandra doesn't look at light that we can see with our eyes. It detects x-rays from the Universe.

What makes X-rays in space? Things that are very hot and energetic, like matter falling into a black hole, or the remains of a star that has exploded, or giant clouds of super-hot gas that surround galaxy clusters.

Astronomers use Chandra to help us better understand how the Universe - and the things in it - work.
[Runtime: 02:38]
(NASA/CXC/April Jubett)

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7. Chandra Sketches: Clara's Launch
QuicktimeMPEG My mom works for NASA, for a telescope that studies X-rays from space. She told me about how the telescope, called Chandra, was launched into space aboard the Space Shuttle. That shuttle flight had a woman commander named Eileen Collins. There was another woman astronaut, Cady Coleman, who used a robotic arm to put the telescope into space. (I also learned about them in school from my teacher, Mrs. Panciocco!) These women studied Science and Math and do really interesting things.

My mom knows these women, and it is great that I get to learn about them. Maybe I will be a scientist some day. Or an astronaut. Or maybe I could work for NASA like my mom.

By Clara, age 9.
[Runtime: 02:09]
(NASA/CXC/A. Hobart)

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8. Introduction to OpenFITS
QuicktimeMPEG Hello and welcome to the Chandra X-ray Observatory's first OpenFITS tutorial screencast. I'm Joe DePasquale, Science Imager for Chandra, and today I'd like to introduce you to our OpenFITS tutorials. OpenFITS can be reached from the main Chandra website ( We developed OpenFITS several years ago with the intent of giving you a behind the scenes look at how we create our colorful images of the universe, but also to put the power into your hands to create those images yourself, using raw data and tutorials on how to combine those data to make color images.

We're excited to announce that we've now added multiwavelength data to our OpenFITS collection. Under the multiwavelength data link, you'll see that there are twenty new images; each one has multiple wavelengths of light available in FITS file format. We've removed some of the stumbling blocks towards creating an image like this by providing data that has already been calibrated, intensity scaled, and plate solved, so that all you need to do is combine these data in the image processing platform of your choice and apply color.

Today, I would like to step through our new tutorial on creating a multiwavelength composite image of M101 using GIMP. At the top of the tutorial page, you will see the links to download the data. This is a Great Observatories image combining Chandra X-ray data, with GALEX ultraviolet, Hubble optical and Spitzer infrared. Now I've already downloaded these data, but for yourself, you will need to right click, and "download file as" to save the data. Next, we will bring up GIMP and open the files as layers in a single GIMP document. We do this using "File->Open As Layers", selecting the four FITS files that we've downloaded, and using the default settings for opening a FITS file in GIMP. Now each image has opened as a layer in a single document.

Before we can apply color to this image, we need to first change the "Image Mode" from "Grayscale" to "RGB". Next we need to allow the layers to show through and to do this, we need to change the "Layer Mode" for each layer from "Normal" to "Screen". By doing that to the infrared layer, I'm now allowing the optical layer underneath to show through. We will apply this change to the optical and UV layers as well.

At this point, we've reached step 4 of the tutorial. Now, as I mentioned in the beginning of the tutorial, these images have already been intensity scaled and calibrated so you really do not need to adjust levels unless you decide you want to. For now, we will skip to step 5, adding color. Starting with the infrared layer, we're going to use the tool "Colors->Colorize" to give the infrared layer a nice red color. A "Hue" value of 0, a "Saturation" of 100, and a "Lightness" of -50 will do this for us. Next, we want to give the optical layer a yellowish-green color. A "Hue" value of 65 works well here, and again a "Saturation" of 100 and "Lightness" of -50. The UV layer, we're going to colorize blue: a "Hue" value of 200, "Saturation" of 100 and "Lightness" of -50. And finally, the X-ray layer, we want to colorize as magenta. A Hue value of about 300 works well here.

And there you have it! In under 5 minutes, we've been able to re-create the Chandra press release image of M101: The Great Observatories image. To finish the image off, we can use "Image->Flatten Image" to create a flattened version and then save it out to the format of our choice. Please explore the twenty new images that we've added to our multiwavelength data collection. If you like what you've created, feel free to share your images on our Facebook page. And, thanks for tuning in!
[Runtime: 04:22]
(NASA/CXC/J. DePasquale)

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9. Hour of Code
QuicktimeMPEG For many us, it's probably hard to imagine living a life without computers and technology. In fact, it's become so much a part of our society that we may not realize how dependent we are on technology.

But who does the work that enables these computers to fit into our daily lives? Who gets to learn how to code? A project called "Hour of Code" as well as Computer Science Education Week is seeking to address that question by increasing access to coding opportunities for elementary, middle and high school students. The Hour of Code project is particularly interested in getting more girls and all students from underrepresented people of color involved in coding.

Here at the Chandra X-ray Center, we have tried to be as active as possible in expanding the pool of students who go into the fields of science, technology, engineering, and math, also known as "STEM." The inclusion of computer science to this list seemed like an excellent idea, so we gladly signed up for the "Hour of Code" project.

The Chandra X-ray Center has joined forces with other members of the astronomical community, including an astronomer at the American Astronomical Society, others at the Smithsonian Astrophysical Observatory, as well as partners at Google's CS First and Pencil Code, to create a project for the "Hour of Code" that combines color, astronomy, and coding.

Working with NASA and other data from exploded stars, to star-forming regions, to the area around black holes, students learn basic coding (for beginners - no experience required) and follow a video tutorial to create a real world application of science, technology and even art.

Kimberly Arcand directs visualizations and other communications projects at the Chandra X-ray Center, and she led Chandra's contribution to the project. She explains why she feels projects like "Hour of Code" are so important.

Here at Chandra, we get to explore the Universe and computers help us do that. I use coding and computers to help tell stories about science, whether that story takes the form of an image of a galaxy, or a 3 dimensional printable model of an exploded star, or a simple program that lets people see a cluster of young stars in different kinds of light.

Computer science allows anyone to create new things and solve problems. Coding isn't just important in astronomy, but all fields of science. I want to help make sure that anyone can feel like coding and computer science is possible for them. Projects such as the "Hour of Code" and "Pencil Code" can help make that a reality.

By enabling students to use real data from NASA's Chandra X-ray Observatory, along with other astronomical data, this project helps show just how integral coding is in the pursuit of learning about our Universe. We hope it's an example of the exciting ways that computer science - from routine tasks in our everyday lives to the extraordinary quest to explore the cosmos - is part of it all.
[Runtime: 03:56]
(NASA/CXC/A. Hobart)

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10. Chandra - 15 Years and Counting
QuicktimeMPEG Celebrating 15 years of science with NASA's Chandra X-ray Observatory: Chandra allows scientists from around the world to obtain X-ray images of exotic environments to help understand the structure and evolution of the universe. NASA's Marshall Space Flight Center in Huntsville, Alabama, manages the Chandra program for NASA's Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory in Cambridge, Massachusetts, controls Chandra's science and flight operations.
[Runtime: 14:30]

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