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Finding Darkness In The Light: How Vera Rubin Changed The Universe

“Instead, the speeds rose rapidly, but then leveled off. As you moved farther away from a galaxy’s core, the stars’ rotation speeds didn’t drop, but rather leveled off to a constant value. The rotation curves, unexpectedly, were flat. Rubin’s work began in the Andromeda galaxy, our closest large, galactic neighbor, but quickly was extended to dozens of galaxies, which all showed the same effects. Today, that number is in the thousands, and our multiwavelength, advanced surveys have shown that it can’t be missing atoms, ions, plasmas, gas, dust, planets or asteroids that account for the mass. Either something is screwy with the laws of gravity on galactic (and larger) scales, or there’s some type of unseen mass in the Universe.”

When you look at a galaxy in the night sky, it’s easy to imagine that it’s just a system of masses like our Solar System, except on a larger scale. Instead of a single, central mass, you have many stars responsible for the galaxy’s gravitational pull. The stars revolving around the galactic center feel the tug from all the other stars and orbit accordingly, with the inner stars orbiting quickly and the outermost ones – the ones most distant from the gravitational sources – orbiting more slowly, just like the planets. At least, that’s what you’d expect. But when the techniques and the technologies for measuring this finally came to fruition, the result was a colossal surprise: the stars in a galaxy didn’t determine the galaxy’s mass or rotation properties. In fact, if you went out and measured the gas, dust, plasma, planets and everything else we can observe in the galaxy, they don’t explain it either. Something unseen and invisible was influencing the way galaxies behave.

On Sunday night, Vera Rubin passed away at age 88. Here was her most titanic, Universe-changing contribution to the enterprise of science.

astrophysics-official

How do we know light is a wave?

Before I answer this question, I’ll need to briefly go over a wave property called superposition. Basically, superposition is the idea that two waves can be in the same position at the same time, and interfere with each other:

When the two waves add to each other and make a larger wave, we call this constructive interference. When the waves cancel each other out, we call this destructive interference.

Now we’re going to move on to the Double Slit Experiment. Basically, you shine a beam of light at a piece of metal, cardboard, etc with two slits in it, with a surface behind it where you can see the light hit it.

If light is a wave, what we’d expect to see would be an interference pattern created by the light from the first slit interfering with light from the second slit, which is exactly what we see. It’s a pattern of constructive interference (brighter regions) and destructive interference (darker regions), looking like this:

These images are helpful:

that is how we know light acts as a wave!!

astropeggy

The NASA Village

Today in the NASA Village… A Form of (EM)Powerment

Does the formula above ring a bell?

Most of us learn the quadratic formula sometime around high school algebra, alongside lessons involving roots and imaginary numbers.

In case you were wondering, the formula is used to solve parabolic equations, and yes—we do use parabolas to help us understand properties of space travel.

This formula brings up fond memories for Lydia Davis, Electrical Engineer and current Aerospace Technologist for Electrical Power Systems at NASA. She had memorized this powerful equation by age five!

“I remember singing the quadratic formula song before I knew what it was used for,” Davis said.

Davis’s dedication to math and science she attributes to her mother, who has taught high school mathematics for over 25 years. This led to Davis’s path in pursuing an engineering degree at the University of Kentucky. “I wanted to become an engineer so I could solve real-world problems,” Davis said. “In college, I knew I wanted to work as an electrical engineer for NASA. I was able to achieve my goal through endless hours of studying, hard work, and never giving up.” Even in in generation Z, becoming an engineer required self-confidence. Davis had been working towards this goal since high school, and had no intentions of putting her dreams aside for anything less than what she started out to do. “Being a women in a predominately male career field can be intimidating—but never forget we are just as capable as our male counterparts.”

I’m sure the 1979 first female astronaut training class would agree.

Davis has proudly done her part in contributing to a more diverse workforce through her work with electrical power systems used aboard the International Space Station:

As well as wielded some of the power tools required to build components for a hands-on experience:

Davis has also learned that confidence comes with time, and experience. “I quickly learned that I needed to feel comfortable asking questions, speaking my mind in discussions, and finding training and research opportunities to further develop myself and my technical expertise.” Without a mindset for asking questions, Davis would have never learned some of the fun facts she’s learned since starting her job as an engineer for NASA.

Did you know that the space station flies over your head each day, and is about the size of a football field?

http://www.nasa.gov/mission_pages/station/main/onthestation/facts_and_figures.html

The space station has over eight miles of cables connecting the Electrical Power System, and generates its power with eight solar array wings:

Each wing is capable of supplying about 25 kW of power each, though only 10 kW of power are used per channel. These electrical systems to support critical operations in space don’t build themselves.

Thanks to the Electrical Power Systems team for (em)powering us in our journey!

Do you want more stories? Find our NASA Villagers here!

imcubo

Some 40 light-years from Earth, a planet called TRAPPIST-1e offers a heart-stopping view: brilliant objects in a red sky, looming like larger and smaller versions of our own moon. But these are no moons. They are other Earth-sized planets in a spectacular planetary system outside our own. These seven rocky worlds huddle around their small, dim, red star, like a family around a campfire. Any of them could harbor liquid water, but the planet shown here, fourth from the TRAPPIST-1 star, is in the habitable zone, the area around the star where liquid water is most likely to be detected. This system was revealed by the TRansiting Planets and PlanetIsmals Small Telescope (TRAPPIST) and NASA’s Spitzer Space Telescope. The planets are also excellent targets for NASA’s James Webb Space Telescope. Take a planet-hopping excursion through the TRAPPIST-1 system.

senes-aeterni

so cute

rjzimmerman

American scientists should learn from their northern neighbors. Reject interference. Stay vigilant. Stay scientists.

The trump cabal, and the right-wing extremists in the Congress and in state capitals, have commenced a process, politically motivated, to stifle scientific inquiry and sharing with the public of the results of scientific inquiry. Canada went through a similar period recently during the Stephen Harper leadership era. This essay addresses that.

Excerpt:

Just as the American science community is now struggling with whether to speak out and march or stay quiet and do its work, Canadian scientists wrestled with the same questions. Ultimately, Canada’s scientific community came together to save our research, galvanized support to fight back, and captured the attention and concern of the public. I hope our experience — in the spirit of science transcending borders — can be instructive.

Here’s our advice as the Trump administration gears up. Spotlight and champion scientists’ refusal to kowtow to intimidation. Come together, speak up and speak out. Scientists must recognize and fight political censorship, while they remain vigilant for political interference. Share documents widely and back up data in a secure location if the administration politicizes or interferes in research.

Evidence and objective reality are the foundation of successful policy and governance. Openness is as vital to science as it is to democracy. We cannot allow hard-won knowledge to be ignored or distorted. To fight the snuffing of the light of scientific inquiry, learn from your neighbors to the north. Reject interference. Stay vigilant and stay vocal. In other words, stay scientists.

astrophysicsstudent

teded

What are von Neumann machines?

Decades ago, scholars found that it’s theoretically possible to not just spread human civilization across the galaxy, but to do so quite quickly, without breaking any known laws of physics. Their idea is based on the work of a mathematician named John von Neumann, who designed on paper machines that could self-replicate and create new generations of themselves. These would later come to be known as von Neumann machines.

In the context of space exploration, von Neumann machines could be built on Earth and launched into space. There, the self-sufficient machines would land on distant planets. They would then mine the available resources and harvest energy, build replicas of themselves, launch those to the nearest planets, and continue the cycle. The result is the creation of millions of probes spreading outwards into the universe like a drop of ink in a fishbowl.

Scholars crunched the numbers and found that a single von Neumann machine traveling at 5% of the speed of light should be able to replicate throughout our galaxy in 4 million years or less. That may sound like a long time, but when you consider that our universe is 14 billion years old, on a cosmic scale, it’s incredibly fast - the equivalent of about 2.5 hours in an entire year.

Creating von Neumann machines would require a few technologies we don’t have yet, including advanced artificial intelligence, miniaturization, and better propulsion systems. If we wanted to use them to spread actual humans throughout the galaxy, we would need yet another technological leap - the ability to artificially grow biological organisms and bodies using raw elements and genetic information.

Regardless, if in the last billion years an alien civilization created such a machine and set it multiplying its way toward us, our galaxy would be swarming with them by now. So then where are all these machines? Some astronomers, like Carl Sagan, say that intelligent aliens wouldn’t build self-replicating machines at all. They might hurtle out of control, scavenging planets to their cores in order to keep replicating. Others take the machines absence as proof that intelligent alien civilizations don’t exist, or that they go extinct before they can develop the necessary technologies.

But all this hasn’t stopped people from imagining what it would be like if they were out there. Science fiction author David Brin writes about a universe in which many different von Neumann machines exist and proliferate simultaneously. Some are designed to greet young civilizations, others to locate and destroy them before they become a threat. For now, all we have is curiosity and theory. But the next time you look at the night sky, consider that billions of self-replicating machines could be advancing between stars in our galaxy right now. If they exist, one of them will eventually land on Earth, or maybe, just maybe, they’re already here.

From the TED-Ed Lesson Could human civilization spread across the whole galaxy? - Roey Tzezana

Animation by Eion Duffy

#science #space #physics #newtonslawofsand

bad-wolf-ash

In biology you study living things. In chemistry you learn how to kill those living things.

My chem teacher (via silvertardis1276)

missaerospaceblog

Teenage girls to launch Africa’s first private space satellite

They may be teenagers, but 17-year-old Brittany Bull and 16-year-old Sesam Mngqengqiswa have grand ambitions – to launch Africa’s first private satellite into space.

They are part of a team of high school girls from Cape Town, South Africa, who have designed and built payloads for a satellite that will orbit over the earth’s poles scanning Africa’s surface…

mathblab

Isn’t interesting to live in our time and have such wonderful puzzles to work on?

Richard Feynman (via mathblab)

teded

The physics of the "hardest move" in ballet

In the third act of “Swan Lake”, the Black Swan pulls off a seemingly endless series of turns, bobbing up and down on one pointed foot and spinning around and around and around … thirty-two times. It’s one of the toughest sequences in ballet, and for those thirty seconds or so, she’s like a human top in perpetual motion.

Those spectacular turns are called fouettés, which means “whipped” in French, describing the dancer’s incredible ability to whip around without stopping. But while we’re marveling at the fouetté, can we unravel its physics?

The dancer starts the fouetté by pushing off with her foot to generate torque. But the hard part is maintaining the rotation. As she turns, friction between her pointe shoe and the floor, and somewhat between her body and the air, reduces her momentum. So how does she keep turning? Between each turn, the dancer pauses for a split second and faces the audience. Her supporting foot flattens, and then twists as it rises back onto pointe, pushing against the floor to generate a tiny amount of new torque.

At the same time, her arms sweep open to help her keep her balance. The turns are most effective if her center of gravity stays constant, and a skilled dancer will be able to keep her turning axis vertical.

The extended arms and torque-generating foot both help drive the fouetté. But the real secret and the reason you hardly notice the pause is that her other leg never stops moving. During her momentary pause, the dancer’s elevated leg straightens and moves from the front to the side, before it folds back into her knee.

By staying in motion, that leg is storing some of the momentum of the turn. When the leg comes back in towards the body, that stored momentum gets transferred back to the dancer’s body, propelling her around as she rises back onto pointe.

As the ballerina extends and retracts her leg with each turn, momentum travels back and forth between leg and body, keeping her in motion.

In Tchaikovsky’s ballet, the Black Swan is a sorceress, and her 32 captivating fouettés do seem almost supernatural. But it’s not magic that makes them possible. It’s physics.

From the TED-Ed Lesson The physics of the “hardest move” in ballet - Arleen Sugano

Animation by Dancing Line Productions

skunkbear

Folks are getting excited about recent reports of an “interesting” signal picked up by the Search for Extra-Terrestrial Intelligence (SETI). SETI scientists say you shouldn’t get your hopes up - it’s probably not aliens.

**UPDATE: Definitely not aliens! - a Soviet Era satellite instead.**

The incident reminded me of another potential brush with E.T. back in 1977: The Wow! Signal. Robert Krulwich wrote a blog post all about it if you want to learn more. And for a more technical description, check out a report from Jerry Ehman, the man who wrote “Wow!”

Images: Big Ear Radio Observatory and North American AstroPhysical Observatory, Patrick Foto/Getty Images

rejectedprincesses

High school student Maia Dua has won the top prize in Marvel Studio's Girls Reforming the Future Challenge. Let's have a look at the robot she built!

For the launch of Captain America: Civil War, Marvel had a contest for girls in STEM to show off their inventions. And they just announced the winners.

Maia Dua won with her prototype “seeing eye” robot, which provides cost-effective help for the vision-impaired for whom options like seeing eye dogs are not viable.

The other finalists included Holly Riepling from Colorado Springs, Colo.; Janie Kim from San Diego, Calif.; Margaret Fleck from Emmanus, Pa.; and Vivian Qiang from Marlboro, N.J.

They got to walk the red carpet and attend the Civil War premiere. And they all seem like pretty damn cool people.

mysteriousquantumphysics

I've just recently interested in physics, especially quantum physics and astrophysics. I want to study it, but don't know where to start. I wasn't good at science subjects in high school. Do you have any advice for a beginner?

If I was you I would read some popular scientific books about the topics i like. Books of Brian Greene, Stephen Hawking and Michio Kaku are great:)

nasa

Exploring an Asteroid Without Leaving Earth

You may remember that back in February, four crew members lived and worked inside our Human Research Exploration Analog (HERA). That crew, made up of 4 women, simulated a 715-day journey to a Near-Earth asteroid. That 30 day mission helped our researchers learn how isolation and close quarters affect individual and group behavior. Studies like this at our Johnson Space Center prepare us for long duration space missions, like a trip to an asteroid or even to Mars.

We now have another crew, made up of four men, living and working inside the HERA. This is the spacecraft’s 10th crew. The mission began on May 3, and will end on June 1.

The crew members are currently living inside this compact, science-making house. But unlike in a normal house, these inhabitants won’t go outside for 30 days. Their communication with the rest of planet Earth will also be very limited, and they won’t have any access to internet. The only people they will talk with regularly are mission control and each other.

The HERA X crew is made up of four males selected from the Johnson Space Center Test Subject Screening (TSS) pool. The crew member selection process is based on a number of criteria, including the same criteria for astronaut selection. The four would-be astronauts are:

Ron Franco

Oscar Mathews

Chris Matty

Casey Stedman

Lisa Spence, the Human Research Program’s Flight Analogs Project Manager, explained that ideally they would like the four-person crews to be two males and two females. Due to the applicant pool, HERA IX was an all female crew, and HERA X (this current mission) is all male.

What will they be doing?

The crew will test hardware prototypes to get “the bugs worked out” before they are used in off-Earth missions. They will conduct experiments involving plants, brine shrimp, and creating a pice of equipment with a 3D printer. After their visit to an asteroid, the crew will simulate the processing of soil and rocks they collected virtually. Researchers outside of the spacecraft will collect data regarding team dynamics, conflict resolution and the effects of extended isolation and confinement.

How real is a HERA mission?

When we set up an analog research investigation, we try to mimic as many of the spaceflight conditions as we can. This simulation means that even when communicating with mission control, there will be a delay on all communications ranging from 1 to 5 minutes each way, depending on how far their simulated spacecraft is from Earth.

Obviously we are not in microgravity, so none of the effects of microgravity on the human or the vehicle can be tested. You can mimic isolation to some degree – although the crew knows they are note really isolated from humanity, the communications delays and ban from social media help them to suspend reality. We mimic confinement and the stress that goes along with it.

Scientists and researchers use analogs like HERA to gather more data for comparison to data collected aboard the space station and from other analogs so they can draw conclusions needed for a real mission to deep space, and one day for a journey to Mars.

A few other details:

The crew follows a timeline that is similar to one used for the ISS crew.

They work 16 hours a day, Monday through Friday. This includes time for daily planning, conferences, meals and exercises.

They will be growing and taking care of plants and brine shrimp, which they will analyze and document.

Past HERA crew members wore a sensor that recorded heart rate, distance, motion and sound intensity. When crew members were working together, the sensor would also record their proximity as well, helping investigators learn about team cohesion.

Researchers also learned about how crew members react to stress by recording and analyzing verbal interactions and by analyzing “markers” in blood and saliva samples.

In total, this mission will include 22 individual investigations across key human research elements. From psychological to physiological experiments, the crew members will help prepare us for future missions.

Want a full, 360 degree look at HERA? Check out and explore the inside of the habitat.

For more information on our Human Research Program, visit: www.nasa.gov/hrp.

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

scienceprofessorquotes

Electrons are like children. You can’t tell them where to go. They don’t like to listen.

Organic chemistry professor (via scienceprofessorquotes)

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