What’s Your Favorite Black Hole Fact That You Like To Share With People?

Today we celebrate the mission that piqued our curiosities, and drove NASA’s perseverance to pursue further exploration of the Red Planet. The Sojourner rover landed on July 4, 1997, after hitching a ride aboard the Mars Pathfinder mission. Its innovative design became the template for future missions. The rover, named after civil rights pioneer Sojourner Truth, outlived its design life 12 times. This panoramic view of Pathfinder's Ares Vallis landing site shows Sojourner rover is the distance. Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com 

Hopefully not a total dumb question but, YOUR ultimate goal as an astronaut?

Which Landsat Image Do You Love?

Feeling competitive? We’ve got a game for you to play in! Tournament Earth: The Landsat Games is happening right now, and as we get to the final entries, the competition is heating up.

You can help us pick the winner by voting for one of the remaining four Landsat images of our home planet! Our competition started with 32 images, divided into categories by what they show: land, water, ice & snow, and human impact.

So, what do you think? Which one of these images is going for gold?

Land

First up, we have an image of the Markha River and surrounding Central Siberian Plateau, acquired in 2020 by Landsat 8. The hypnotic undulations of striping across the landscape carried this image to victory over the rest of the Land images -- a particularly tough category, given that these images all come from Landsat.

Water

It’s not all land, though! The bright blues and greens of this false-color image of the Atchafalaya Delta in Louisiana helped carry it to victory in the Water category. The image, taken in 2020 by Landsat 8, shows a region that’s subject to erosion of land by wind and rising sea levels.

Ice & Snow

Brrr! Did it get cold in here? That’s the finalist from the Ice and Snow category, an image of sea ice around Russia’s New Siberian Islands. The image, collected by Landsat 8 in June 2016, shows sea ice during its annual seasonal breakup.

Human Impact

Humans have been shaping the planet around us for hundreds of years. Some changes, like rice fields in the Sacramento Valley, are visible from space. Landsat 8 collected this false-color image of flooded rice fields in December 2018.

So, now it’s up to you! Which image is your favorite? There can only be one winner of Tournament Earth: The Landsat Games. Get your vote in, and then get ready to watch as we launch the next Landsat satellite, Landsat 9, in September.

The Landsat mission is a partnership between us at NASA and the U.S. Geological Survey. Together, we’ve been using Landsat satellites to collect nearly 50 years of images of our home planet.

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What was your first thought when you first saw earth from space? And what realizations did you have?

Dark Matter 101: Looking for the missing mass

Here’s the deal — here at NASA we share all kinds of amazing images of planets, stars, galaxies, astronauts, other humans, and such, but those photos can only capture part of what’s out there. Every image only shows ordinary matter (scientists sometimes call it baryonic matter), which is stuff made from protons, neutrons and electrons. The problem astronomers have is that most of the matter in the universe is not ordinary matter – it’s a mysterious substance called dark matter.  

What is dark matter? We don’t really know. That’s not to say we don’t know anything about it – we can see its effects on ordinary matter. We’ve been getting clues about what it is and what it is not for decades. However, it’s hard to pinpoint its exact nature when it doesn’t emit light our telescopes can see. 

Misbehaving galaxies

The first hint that we might be missing something came in the 1930s when astronomers noticed that the visible matter in some clusters of galaxies wasn’t enough to hold the cluster together. The galaxies were moving so fast that they should have gone zinging out of the cluster before too long (astronomically speaking), leaving no cluster behind.

Simulation credit: ESO/L. Calçada

It turns out, there’s a similar problem with individual galaxies. In the 1960s and 70s, astronomers mapped out how fast the stars in a galaxy were moving relative to its center. The outer parts of every single spiral galaxy the scientists looked at were traveling so fast that they should have been flying apart.

Something was missing – a lot of it! In order to explain how galaxies moved in clusters and stars moved in individual galaxies, they needed more matter than scientists could see. And not just a little more matter. A lot . . . a lot, a lot. Astronomers call this missing mass “dark matter” — “dark” because we don’t know what it is. There would need to be five times as much dark matter as ordinary matter to solve the problem.  

Holding things together

Dark matter keeps galaxies and galaxy clusters from coming apart at the seams, which means dark matter experiences gravity the same way we do.

In addition to holding things together, it distorts space like any other mass. Sometimes we see distant galaxies whose light has been bent around massive objects on its way to us. This makes the galaxies appear stretched out or contorted. These distortions provide another measurement of dark matter.

Undiscovered particles?

There have been a number of theories over the past several decades about what dark matter could be; for example, could dark matter be black holes and neutron stars – dead stars that aren’t shining anymore? However, most of the theories have been disproven. Currently, a leading class of candidates involves an as-yet-undiscovered type of elementary particle called WIMPs, or Weakly Interacting Massive Particles.

Theorists have envisioned a range of WIMP types and what happens when they collide with each other. Two possibilities are that the WIMPS could mutually annihilate, or they could produce an intermediate, quickly decaying particle. In both cases, the collision would end with the production of gamma rays — the most energetic form of light — within the detection range of our Fermi Gamma-ray Space Telescope.

Tantalizing evidence close to home

A few years ago, researchers took a look at Fermi data from near the center of our galaxy and subtracted out the gamma rays produced by known sources. There was a left-over gamma-ray signal, which could be consistent with some forms of dark matter.

While it was an exciting finding, the case is not yet closed because lots of things at the center of the galaxy make gamma rays. It’s going to take multiple sightings using other experiments and looking at other astronomical objects to know for sure if this excess is from dark matter.

In the meantime, Fermi will continue the search, as it has over its 10 years in space. 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.  

How Do We Learn About a Planet’s Atmosphere?

The first confirmation of a planet orbiting a star outside our solar system happened in 1995. We now know that these worlds – also known as exoplanets – are abundant. So far, we’ve confirmed more than 4000. Even though these planets are far, far away, we can still study them using ground-based and space-based telescopes.

Our upcoming James Webb Space Telescope will study the atmospheres of the worlds in our solar system and those of exoplanets far beyond. Could any of these places support life? What Webb finds out about the chemical elements in these exoplanet atmospheres might help us learn the answer.

How do we know what’s in the atmosphere of an exoplanet?

Most known exoplanets have been discovered because they partially block the light of their suns. This celestial photo-bombing is called a transit.

During a transit, some of the star's light travels through the planet's atmosphere and gets absorbed.

The light that survives carries information about the planet across light-years of space, where it reaches our telescopes.

(However, the planet is VERY small relative to the star, and VERY far away, so it is still very difficult to detect, which is why we need a BIG telescope to be sure to capture this tiny bit of light.)

So how do we use a telescope to read light?

Stars emit light at many wavelengths. Like a prism making a rainbow, we can separate light into its separate wavelengths. This is called a spectrum. Learn more about how telescopes break down light here. 

Visible light appears to our eyes as the colors of the rainbow, but beyond visible light there are many wavelengths we cannot see.

Now back to the transiting planet...

As light is traveling through the planet's atmosphere, some wavelengths get absorbed.

Which wavelengths get absorbed depends on which molecules are in the planet's atmosphere. For example, carbon monoxide molecules will capture different wavelengths than water vapor molecules.

So, when we look at that planet in front of the star, some of the wavelengths of the starlight will be missing, depending on which molecules are in the atmosphere of the planet.

Learning about the atmospheres of other worlds is how we identify those that could potentially support life...

...bringing us another step closer to answering one of humanity's oldest questions: Are we alone?

Watch the full video where this method of hunting for distant planets is explained:

To learn more about NASA’s James Webb Space Telescope, visit the website, or follow the mission on Facebook, Twitter and Instagram. 

Text and graphics credit Space Telescope Science Institute

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

NASA Spotlight: Astronaut Jonny Kim

Dr. Jonny Kim was selected by NASA to join the 2017 Astronaut Candidate Class. He reported for duty in August 2017 and having completed the initial astronaut candidate training is now eligible for mission assignments to the International Space Station, the Moon and eventually Mars. A U.S. Navy SEAL, Kim completed more than 100 combat operations. Kim was commissioned as a naval officer through an enlisted-to-officer program and earned his degree in mathematics at the University of San Diego and a doctorate of medicine at Harvard Medical School. Born and raised in Los Angeles, California to Korean-American immigrants, he enjoys spending time with his family, outdoor activities, academic and professional mentoring, strength training and lifelong learning. 

Dr. Kim took some time from his job as a NASA astronaut to answer questions about his life and career! Enjoy: 

Why did you apply to be an astronaut?

For many reasons. I think that humans are natural explorers. There is a calling in all of us to explore the unknown, push the boundaries and redefine what is possible. I’m drawn to the physical and mental challenges of space exploration and the teamwork required to complete such an objective. And finally, the opportunity to do something good for our country, for humanity, and to inspire the next generation of thinkers, leaders, explorers and scientists.

What was your favorite memory from astronaut training?

I’m a big believer that people can grow stronger bonds with each other when they succeed through shared hardship. And I think that developing relationships with one another is one of the best ways to forge successful team skills to be successful in any endeavor. With that context, I can tell you that my favorite memory from astronaut training was traversing the deep canyon slots of the Utah Canyon Lands for almost 2 weeks with my classmates. We hiked trails, climbed canyons, swam through deep, dark, cold and murky waters and forged through uncertainty, all while being together. This shared hardship was not only fun, but it helped us grow closer to one another. It’s one of the fondest memories I have when I think about my amazing classmates, and through that shared hardship, I know I can count on any one of my fellow astronauts when the going gets tough.

If you could play any song during launch, what would it be?

Don’t Stop Believin’ by Journey.

What advice would you give to your younger self?

I would tell myself to always follow your passion, never stature or money, because following a life of passion is long-term, sustainable and usually helps others. Be accountable for your mistakes and failures, and maintain the humility to learn from those mistakes and failures. And finally, I would caution myself that all worthwhile goals are difficult to obtain, but with the right attitude and hard work, you can accomplish anything.

How did your time as a Navy Seal impact your astronaut training?

Being a Naval Special Warfare Operator taught me that humans are capable of accomplishing ten times what their bodies and mind tell them. I learned there are no limits in life, and the biggest setback one can have is a poor attitude. I learned the value of strong leadership and accountability. I also learned the meaning of sacrifice, hardship, teamwork, love and compassion. All these traits helped me to develop the hard and soft skills required to be an astronaut.

How do we prepare medically for long duration missions? What tools, resources, medications do we anticipate needing, and how do we figure that out?

This is a great question and the answer is evolving. The way we answer this question is by being thoughtful and consulting the medical communities to weigh the pros and cons of every single decision we make regarding this. Mass plays an important factor, so we have to be mindful of everything we bring and how we train for it.

Who was the first person you called after being selected to be an astronaut?

It would have been my wife but she was with me when I heard the news. The first person I called was my mom.

What is one item from home that you would bring to space?

A picture of my wife and kids.

What does it mean to you to be part of the Artemis generation of astronauts?

It means that I have a duty and obligation to serve humanity’s best interests. To explore the unknown, push boundaries and redefine what’s possible. It means I have an immense opportunity to serve as an example and inspiration to our next generation of leaders and explorers. It also means there is a hard road ahead, and when the mission calls for us, we will be ready.

What are three personal items, besides photos of family and friends, that you would bring with you on your first spaceflight?

An automatic watch, because the engineering behind a timepiece is a beautiful thing. An American flag, because I proudly believe and uphold the principles and ideals our country stands for. And finally, a nice journal that I can put handwritten thoughts on.

Thank you for your time, and good luck on your first spaceflight assignment!

Follow Jonny Kim on Twitter and Instagram to keep up with his life as NASA astronaut. 

It’s not too late to APPLY to #BeAnAstronaut! Applications close TOMORROW, March 31. 

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

How do blackholes form and how do they move ?

Solar System: From TED Talks to Data Releases

Let us lead you on a journey of our solar system. Here are some things to know this week:

1. NASA-Funded Research

It’s all just a click way with the launch of a new public access site, which reflects our ongoing commitment to provide public access to science data.

Start Exploring!

2.  Red Planet Reconnaissance 

One of the top places in our solar system to look for signs of past or current life is Mars. Through our robotic missions, we have been on and around Mars for 40 years. These orbiters, landers and rovers are paving the way for human exploration.

Meet the Mars robots

3. Three Moons and a Planet that Could Have Alien Life

In a presentation at TED Talks Live, our director of planetary science, Jim Green, discusses the best places to look for alien life in our solar system.

Watch the talk

4. Setting Free a Dragon

Tune in to NASA TV on Friday, Aug. 26 at 5:45 a.m. EDT for coverage of the release of the SpaceX Dragon CRS-9 cargo ship from the International Space Station.

Watch live

5. Anniversary Ring(s)

Aug. 26 marks 35 years since Voyager probe flew by Saturn, delighting scientists with rich data and images. Today, thanks to our Cassini spacecraft, we know much more about the ringed planet.

Learn more about Cassini’s mission to Saturn

Learn more about Voyager 2

Discover the full list of 10 things to know about our solar system this week HERE.

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GALAXY BRAIN 🧠

Our Hubble Space Telescope spotted this planetary nebula in the constellation of Orion. It's really a vast orb of gas in space, with its aging star in the center... but what does it look like to you? 🤔

When stars like the Sun grow advanced in age, they expand and glow red. These so-called red giants then begin to lose their outer layers of material into space. More than half of such a star's mass can be shed in this manner, forming a shell of surrounding gas. At the same time, the star's core shrinks and grows hotter, emitting ultraviolet light that causes the expelled gases to glow.