He Faced All This For You, For You To Be Loved, Blessed, Glorified, Exalted, Satisfied, Accepted, Freed

Three Ways to Travel at (Nearly) the Speed of Light

One hundred years ago, Einstein’s theory of general relativity was supported by the results of a solar eclipse experiment. Even before that, Einstein had developed the theory of special relativity — a way of understanding how light travels through space.

Particles of light — photons — travel through a vacuum at a constant pace of more than 670 million miles per hour.

All across space, from black holes to our near-Earth environment, particles are being accelerated to incredible speeds — some even reaching 99.9% the speed of light! By studying these super fast particles, we can learn more about our galactic neighborhood. 

Here are three ways particles can accelerate:

1) Electromagnetic Fields!

Electromagnetic fields are the same forces that keep magnets on your fridge! The two components — electric and magnetic fields — work together to whisk particles at super fast speeds throughout the universe. In the right conditions, electromagnetic fields can accelerate particles at near-light-speed.

We can harness electric fields to accelerate particles to similar speeds on Earth! Particle accelerators, like the Large Hadron Collider and Fermilab, use pulsed electromagnetic fields to smash together particles and produce collisions with immense amounts of energy. These experiments help scientists understand the Big Bang and how it shaped the universe!

2) Magnetic Explosions!

Magnetic fields are everywhere in space, encircling Earth and spanning the solar system. When these magnetic fields run into each other, they can become tangled. When the tension between the crossed lines becomes too great, the lines explosively snap and realign in a process known as magnetic reconnection. Scientists suspect this is one way that particles — for example, the solar wind, which is the constant stream of charged particles from the Sun — are sped up to super fast speeds.

When magnetic reconnection occurs on the side of Earth facing away from the Sun, the particles can be hurled into Earth’s upper atmosphere where they spark the auroras.

3) Wave-Particle Interactions!

Particles can be accelerated by interactions with electromagnetic waves, called wave-particle interactions. When electromagnetic waves collide, their fields can become compressed. Charged particles bounce back and forth between the waves, like a ball bouncing between two merging walls. These types of interactions are constantly occurring in near-Earth space and are responsible for damaging electronics on spacecraft and satellites in space.

Wave-particle interactions might also be responsible for accelerating some cosmic rays from outside our solar system. After a supernova explosion, a hot, dense shell of compressed gas called a blast wave is ejected away from the stellar core. Wave-particle interactions in these bubbles can launch high-energy cosmic rays at 99.6% the speed of light.

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

What is Gravitational Lensing?

A gravitational lens is a distribution of matter (such as a cluster of galaxies) between a distant light source and an observer, that is capable of bending the light from the source as the light travels towards the observer. This effect is known as gravitational lensing, and the amount of bending is one of the predictions of Albert Einstein’s general theory of relativity.

This illustration shows how gravitational lensing works. The gravity of a large galaxy cluster is so strong, it bends, brightens and distorts the light of distant galaxies behind it. The scale has been greatly exaggerated; in reality, the distant galaxy is much further away and much smaller. Credit: NASA, ESA, L. Calcada

There are three classes of gravitational lensing:

1° Strong lensing: where there are easily visible distortions such as the formation of Einstein rings, arcs, and multiple images.

Einstein ring. credit: NASA/ESA&Hubble

2° Weak lensing: where the distortions of background sources are much smaller and can only be detected by analyzing large numbers of sources in a statistical way to find coherent distortions of only a few percent. The lensing shows up statistically as a preferred stretching of the background objects perpendicular to the direction to the centre of the lens. By measuring the shapes and orientations of large numbers of distant galaxies, their orientations can be averaged to measure the shear of the lensing field in any region. This, in turn, can be used to reconstruct the mass distribution in the area: in particular, the background distribution of dark matter can be reconstructed. Since galaxies are intrinsically elliptical and the weak gravitational lensing signal is small, a very large number of galaxies must be used in these surveys.

The effects of foreground galaxy cluster mass on background galaxy shapes. The upper left panel shows (projected onto the plane of the sky) the shapes of cluster members (in yellow) and background galaxies (in white), ignoring the effects of weak lensing. The lower right panel shows this same scenario, but includes the effects of lensing. The middle panel shows a 3-d representation of the positions of cluster and source galaxies, relative to the observer. Note that the background galaxies appear stretched tangentially around the cluster.

3° Microlensing: where no distortion in shape can be seen but the amount of light received from a background object changes in time. The lensing object may be stars in the Milky Way in one typical case, with the background source being stars in a remote galaxy, or, in another case, an even more distant quasar. The effect is small, such that (in the case of strong lensing) even a galaxy with a mass more than 100 billion times that of the Sun will produce multiple images separated by only a few arcseconds. Galaxy clusters can produce separations of several arcminutes. In both cases the galaxies and sources are quite distant, many hundreds of megaparsecs away from our Galaxy.

Gravitational lenses act equally on all kinds of electromagnetic radiation, not just visible light. Weak lensing effects are being studied for the cosmic microwave background as well as galaxy surveys. Strong lenses have been observed in radio and x-ray regimes as well. If a strong lens produces multiple images, there will be a relative time delay between two paths: that is, in one image the lensed object will be observed before the other image.

As an exoplanet passes in front of a more distant star, its gravity causes the trajectory of the starlight to bend, and in some cases results in a brief brightening of the background star as seen by a telescope. The artistic concept illustrates this effect. This phenomenon of gravitational microlensing enables scientists to search for exoplanets that are too distant and dark to detect any other way.Credits: NASA Ames/JPL-Caltech/T. Pyle

Explanation in terms of space–time curvature

Simulated gravitational lensing by black hole by: Earther

In general relativity, light follows the curvature of spacetime, hence when light passes around a massive object, it is bent. This means that the light from an object on the other side will be bent towards an observer’s eye, just like an ordinary lens. In General Relativity the speed of light depends on the gravitational potential (aka the metric) and this bending can be viewed as a consequence of the light traveling along a gradient in light speed. Light rays are the boundary between the future, the spacelike, and the past regions. The gravitational attraction can be viewed as the motion of undisturbed objects in a background curved geometry or alternatively as the response of objects to a force in a flat geometry.

A galaxy perfectly aligned with a supernova (supernova PS1-10afx) acts as a cosmic magnifying glass, making it appear 100 billion times more dazzling than our Sun. Image credit: Anupreeta More/Kavli IPMU.

To learn more, click here. 

(Source)

cosmic microwave background

The cosmic microwave background (CMB) is electromagnetic radiation as a remnant from an early stage of the universe in Big Bang cosmology. In older literature, the CMB is also variously known as cosmic microwave background radiation (CMBR) or “relic radiation”. The CMB is a faint cosmic background radiation filling all space that is an important source of data on the early universe because it is the oldest electromagnetic radiation in the universe, dating to the epoch of recombination.

With a traditional optical telescope, the space between stars and galaxies (the background) is completely dark. However, a sufficiently sensitive radio telescope shows a faint background noise, or glow, almost isotropic, that is not associated with any star, galaxy, or other object. This glow is strongest in the microwave region of the radio spectrum. The accidental discovery of the CMB in 1964 by American radio astronomers Arno Penzias and Robert Wilson was the culmination of work initiated in the 1940s, and earned the discoverers the 1978 Nobel Prize in Physics.

The discovery of CMB is landmark evidence of the Big Bang origin of the universe. When the universe was young, before the formation of stars and planets, it was denser, much hotter, and filled with a uniform glow from a white-hot fog of hydrogen plasma. As the universe expanded, both the plasma and the radiation filling it grew cooler. When the universe cooled enough, protons and electrons combined to form neutral hydrogen atoms. Unlike the uncombined protons and electrons, these newly conceived atoms could not absorb the thermal radiation, and so the universe became transparent instead of being an opaque fog. Cosmologists refer to the time period when neutral atoms first formed as the recombination epoch, and the event shortly afterwards when photons started to travel freely through space rather than constantly being scattered by electrons and protons in plasma is referred to as photon decoupling.

Basically, cosmic microwave background radiation is the fossil of light, resulting from a time when the Universe was hot and dense, only 380,000 years after the Big Bang.

Cosmic microwave background radiation is an electromagnetic radiation that fills the entire universe, whose spectrum is that of a blackbody at a temperature of 2.725 kelvin.

Cosmic microwave background radiation, along with the spacing from galaxies and the abundance of light elements, is one of the strongest observational evidences of the Big Bang model, which describes the evolution of the universe. Penzias and Wilson received the Nobel Prize in Physics in 1978 for this discovery

source, source in portuguese

images credit:  Image credit: Institute of Astronomy / National Tsing Hua University/ NASA/ESA Hubble, wikipedia

NASA Astronauts And Satellites Capture Breathtaking Images Of An Awakening Volcano From Space

“Volcanoes are some of the most fascinating but also dangerous and deadly natural disasters. Fortunately, with appropriate monitoring, they’re one of the most easily mitigated classes of disasters as well. There are approximately 1,500 potentially active volcanoes on Earth at any time, which doesn’t include undersea volcanoes that have not reached the surface or inactive ones that might surprise us.

Only by continuously monitoring the entire Earth at the appropriate resolutions and cadences can we hope to truly minimize the risk to human life and property. Attempts to cut back on this endeavor harm and endanger us all, while an awareness and appreciation for what Earth observing brings us is our greatest asset. May the beauty of these pictures point the way to the most important truth: that comprehensive knowledge and more information are absolutely key to optimally navigating the challenges of being human on our living planet Earth.”

Just a few days ago, on June 22, 2019, a volcano that hadn’t erupted in nearly a century suddenly sprang to life, belching out waves of ash and volcanic gas high into the stratosphere and posing severe threats to nearby life. But far more at-risk were airplanes, which routinely fly through the region where volcanic ash particles were spewed by this eruption. Due to our full suite of Earth observatories, with an assist from astronauts aboard the International Space Station and ground-based monitoring, we were able to minimize the danger and avoid significant damage. Without NASA’s commitment to Earth monitoring, a commitment that’s continually fighting off attempted cuts, mitigating the risks of volcanic eruptions would be hamstrung by humanity’s greatest danger: willful ignorance.

Come take a look at the spectacular story of the recent eruption of Raikoke volcano, and learn why Earth observing is so important in the process!

How Big is Our Galaxy, the Milky Way?

When we talk about the enormity of the cosmos, it’s easy to toss out big numbers – but far harder to wrap our minds around just how large, how far and how numerous celestial bodies like exoplanets – planets beyond our solar system – really are.

So. How big is our Milky Way Galaxy?

We use light-time to measure the vast distances of space.

It’s the distance that light travels in a specific period of time. Also: LIGHT IS FAST, nothing travels faster than light.

How far can light travel in one second? 186,000 miles. It might look even faster in metric: 300,000 kilometers in one second. See? FAST.

How far can light travel in one minute? 11,160,000 miles. We’re moving now! Light could go around the Earth a bit more than 448 times in one minute.

Speaking of Earth, how long does it take light from the Sun to reach our planet? 8.3 minutes. (It takes 43.2 minutes for sunlight to reach Jupiter, about 484 million miles away.) Light is fast, but the distances are VAST.

In an hour, light can travel 671 million miles. We’re still light-years from the nearest exoplanet, by the way. Proxima Centauri b is 4.2 light-years away. So… how far is a light-year? 5.8 TRILLION MILES.

A trip at light speed to the very edge of our solar system – the farthest reaches of the Oort Cloud, a collection of dormant comets way, WAY out there – would take about 1.87 years.

Our galaxy contains 100 to 400 billion stars and is about 100,000 light-years across!

One of the most distant exoplanets known to us in the Milky Way is Kepler-443b. Traveling at light speed, it would take 3,000 years to get there. Or 28 billion years, going 60 mph. So, you know, far.

SPACE IS BIG.

Read more here: go.nasa.gov/2FTyhgH

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

A Tiny Satellite Studies Stormy Layers

The gif above shows data taken by an experimental weather satellite of Hurricane Dorian on September 3, 2019. TEMPEST-D, a NASA CubeSat, reveals rain bands in four layers of the storm by taking the data in four different radio frequencies. The multiple vertical layers show where the most warm, wet air within the hurricane is rising high into the atmosphere. Pink, red and yellow show the areas of heaviest rainfall, while the least intense areas of rainfall are in green and blue.

How does an Earth satellite the size of a cereal box help NASA monitor storms? 

The goal of the TEMPEST-D (Temporal Experiment for Storms and Tropical Systems Demonstration) mission is to demonstrate the performance of a CubeSat designed to study precipitation events on a global scale.

If TEMPEST-D can successfully track storms like Dorian, the technology demonstration could lead to a train of small satellites that work together to track storms around the world. By measuring the evolution of clouds from the moment of the start of precipitation, a TEMPEST constellation mission, collecting multiple data points over short periods of time, would improve our understanding of cloud processes and help to clear up one of the largest sources of uncertainty in climate models. Knowledge of clouds, cloud processes and precipitation is essential to our understanding of climate change.

What is a CubeSat, anyway? And what’s the U for?

CubeSats are small, modular, customizable vessels for satellites. They come in single units a little larger than a rubix cube - 10cmx10cmx10cm - that can be stacked in multiple different configurations. One CubeSat is 1U. A CubeSat like TEMPEST-D, which is a 6U, has, you guessed it, six CubeSat units in it.

Pictured above is a full-size mockup of MarCO, a 6U CubeSat that recently went to Mars with the Insight mission. They really are about the size of a cereal box!

We are using CubeSats to test new technologies and push the boundaries of Earth Science in ways never before imagined. CubeSats are much less expensive to produce than traditional satellites; in multiples they could improve our global storm coverage and forecasting data.

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

Pulsar planets are planets that are found orbiting pulsars, or rapidly rotating neutron stars. The first such planet to be discovered was around a millisecond pulsar and was the first extrasolar planet to be confirmed as discovered.

source

How Quantum Physics Allows Us To See Back Through Space And Time

"If it weren’t for this rare transition, from higher energy spherical orbitals to lower energy spherical orbitals, our Universe would look incredibly different in detail. We would have different numbers and magnitudes of acoustic peaks in the cosmic microwave background, and hence a different set of seed fluctuations for our Universe to build its large-scale structure out of. The ionization history of our Universe would be different; it would take longer for the first stars to form; and the light from the leftover glow of the Big Bang would only take us back to 790,000 years after the Big Bang, rather than the 380,000 years we get today.

In a very real sense, there are a myriad of ways that our view into the distant Universe — to the farthest reaches of deep space where we detect the earliest signals arising after the Big Bang — that would be fundamentally less powerful if not for this one quantum mechanical transition. If we want to understand how the Universe came to be the way it is today, even on cosmic scales, it’s remarkable how subtly dependent the outcomes are on the subatomic rules of quantum physics. Without it, the sights we see looking back across space and time would be far less rich and spectacular."

What gives the Universe the properties we see today? Is it gravity, working on the largest of cosmic scales? It plays a role, but perhaps ironically, the subatomic physics that governs electron transitions within atoms is maybe even more important.

This is how quantum physics allows us to see as far out in space and as far back in time as we can. Without it, our Universe would be a very different place.

Parker Solar Probe is Go for Launch

Tomorrow, Aug. 11, we’re launching a spacecraft to touch the Sun.

The first chance to launch Parker Solar Probe is 3:33 a.m. EDT on Aug. 11 from Space Launch Complex 37 at Cape Canaveral Air Force Station in Florida. Launch coverage on NASA TV starts at 3 a.m. EDT at nasa.gov/live.

After launch, Parker Solar Probe begins its daring journey to the Sun’s atmosphere, or corona, going closer to the Sun than any spacecraft in history and facing brutal heat and radiation.

Though Parker Solar Probe weighs a mere 1,400 pounds — pretty light for a spacecraft — it’s launching aboard one of the world’s most powerful rockets, a United Launch Alliance Delta IV Heavy with a third stage added.

Even though you might think the Sun’s massive means things would just fall into it, it’s surprisingly difficult to actually go there. Any object leaving Earth starts off traveling at about 67,000 miles per hour, same as Earth — and most of that is in a sideways direction, so you have to shed most of that sideways speed to make it to the Sun. All that means that it takes 55 times more launch energy to go to the Sun than it does to go to Mars. On top of its powerful launch vehicle, Parker Solar Probe will use seven Venus gravity assists to shed sideways speed.

Even though Parker Solar Probe will lose a lot of sideways speed, it’ll still be going incredibly fast as its orbit draws closer to the Sun throughout its seven-year mission. At its fastest, Parker Solar Probe will travel at 430,000 miles per hour — fast enough to get from Philadelphia to Washington, D.C. in one second — setting the record for the fastest spacecraft in history.

But the real challenge was to keep the spacecraft from frying once it got there.

We’ve always wanted to send a mission to the corona, but we literally haven’t had the technology that can protect a spacecraft and its instruments from its scorching heat. Only recent advances have enabled engineers to build a heat shield that will protect the spacecraft on this journey of extremes — a tricky feat that requires withstanding the Sun’s intense radiation on the front and staying cool at the back, so the spacecraft and instruments can work properly.

The 4.5-inches-thick heat shield is built like a sandwich. There’s a thin layer of carbon material like you might find in your golf clubs or tennis rackets, carbon foam, and then another thin piece of carbon-carbon on the back. Even while the Sun-facing side broils at 2,500 degrees Fahrenheit, the back of the shield will remain a balmy 85 degrees — just above room temperature. There are so few particles in this region that it’s a vacuum, so blocking the Sun’s radiation goes a long way towards keeping the spacecraft cool.

Parker Solar Probe is also our first mission to be named after a living individual: Dr. Eugene Parker, famed solar physicist who in 1958 first predicted the existence of the solar wind.

“Solar wind” is what Dr. Parker dubbed the stream of charged particles that flows constantly from the Sun, bathing Earth and our entire solar system in the Sun’s magnetic fields. Parker Solar Probe’s flight right through the corona allows it to observe the birth of the very solar wind that Dr. Parker predicted, right as it speeds up and over the speed of sound.  

The corona is where solar material is heated to millions of degrees and where the most extreme eruptions on the Sun occur, like solar flares and coronal mass ejections, which fling particles out to space at incredible speeds near the speed of light. These explosions can also spark space weather storms near Earth that can endanger satellites and astronauts, disrupt radio communications and, at their most severe, trigger power outages.

Thanks to Parker Solar Probe’s landmark mission, solar scientists will be able to see the objects of their study up close and personal for the very first time.

Up until now, all of our studies of the corona have been remote — that is, taken from a distance, rather than at the mysterious region itself. Scientists have been very creative to glean as much as possible from their remote data, but there’s nothing like actually sending a probe to the corona to see what’s going on.

And scientists aren’t the only ones along for the adventure — Parker Solar Probe holds a microchip carrying the names of more than 1.1 million people who signed up to send their name to the Sun. This summer, these names and 1,400 pounds of science equipment begin their journey to the center of our solar system.

Three months later in November 2018, Parker Solar Probe makes its first close approach to the Sun, and in December, it will send back the data. The corona is one of the last places in the solar system where no spacecraft has visited before; each observation Parker Solar Probe makes is a potential discovery.

Stay tuned — Parker Solar Probe is about to take flight.

Keep up with the latest on the mission at nasa.gov/solarprobe or follow us on Twitter and Facebook.

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