Mounded, luminous clouds of gas and dust glow in this Hubble image of a Herbig-Haro object known as HH 45. Herbig-Haro objects are a rarely seen type of nebula that occurs when hot gas ejected by a newborn star collides with the gas and dust around it at hundreds of miles per second, creating bright shock waves.
Credit: NASA, ESA, and J. Bally (University of Colorado at Boulder); Processing: Gladys Kober (NASA/Catholic University of America)
This comparison view shows puffing dust bubbles and an erupting gas shell — the final acts of a monster star.
AG Carinae is formally classified as a Luminous Blue Variable because it is hot (blue), very luminous, and variable. Such stars are quite rare because there are not many stars that are so massive. Luminous Blue Variable stars continuously lose mass in the final stages of their life, during which a significant amount of stellar material is ejected into the surrounding interstellar space, until enough mass has been lost that the star has reached a stable state.
AG Carinae is surrounded by a spectacular nebula, formed by material ejected by the star during several of its past outbursts. The nebula is approximately 10 000 years old, and the observed velocity of the gas is approximately 70 kilometres per second. While this nebula looks like a ring, it is in fact a hollow shell rich in gas and dust, the centre of which has been cleared by the powerful stellar wind travelling at roughly 200 kilometres per second.
After presenting two papers not yet submitted for peer review, astrophysicists at Harvard will announce at noon today the first ever evidence of cosmic inflation and the Big Bang. If the astronomer’s findings hold up under scrutiny, their discovery will prove the existence of gravitational waves and likely forever change our understanding of the Universe.
Harvard astronomer Avi Loeb explained to Space.com: ”If it is confirmed, then it would be the most important discovery since the discovery, I think, that the expansion of the universe is accelerating.” Best St. Patty’s day ever.
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.
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This Is Why Quantum Field Theory Is More Fundamental Than Quantum Mechanics
“But the motivation for quantizing the field is more fundamental than that the argument between those favoring perturbative or non-perturbative approaches. You need a quantum field theory to successfully describe the interactions between not merely particles and particle or particles and fields, but between fields and fields as well. With quantum field theory and further advances in their applications, everything from photon-photon scattering to the strong nuclear force was now explicable.”
What’s wrong with quantum mechanics? It might surprise you to hear that the answer is, “it isn’t quantum enough.” The enormous differences between the quantum and the non-quantum Universe are so striking, as we replace:
* continuous matter with discrete particles, * ideal points with dual-nature wave/particle quanta, * and observable properties like position and momentum with quantum mechanical operators containing an inherent uncertainty.
But it’s still not enough. For one, the original (Schroedinger) equation of quantum mechanics doesn’t play nice with relativity, but even the relativistically invariant versions don’t describe reality fully. Why not? Because only the particles are quantized in quantum mechanics. To reveal the full behavior, you need to quantize their fields and interactions, too.
For decades, astronomers searched the cosmos for what is thought to be the first kind of molecule to have formed after the Big Bang. Now, it has finally been found. The molecule is called helium hydride. It’s made of a combination of hydrogen and helium. Astronomers think the molecule appeared more than 13 billion years ago and was the beginning step in the evolution of the universe. Only a few kinds of atoms existed when the universe was very young. Over time, the universe transformed from a primordial soup of simple molecules to the complex place it is today — filled with a seemingly infinite number of planets, stars and galaxies. Using SOFIA, the world’s largest airborne observatory, scientists observed newly formed helium hydride in a planetary nebula 3,000 light-years away. It was the first ever detection of the molecule in the modern universe. Learn more about the discovery:
Helium hydride is created when hydrogen and helium combine.
Since the 1970s, scientists thought planetary nebula NGC 7027—a giant cloud of gas and dust in the constellation Cygnus—had the right environment for helium hydride to exist.
But space telescopes could not pick out its chemical signal from a medley of molecules.
Enter SOFIA, the world’s largest flying observatory!
By pointing the aircraft’s 106-inch telescope at the planetary nebula and using a tool that works like a radio receiver to tune in to the “frequency” of helium hydride, similar to tuning a radio to a favorite station…
…the molecule’s chemical signal came through loud and clear, bringing a decades-long search to a happy end.
The discovery serves as proof that helium hydride can, in fact, exist in space. This confirms a key part of our basic understanding of the chemistry of the early universe, and how it evolved into today’s complexity. SOFIA is a modified Boeing 747SP aircraft that allows astronomers to study the solar system and beyond in ways that are not possible with ground-based telescopes. Find out more about the mission at www.nasa.gov/SOFIA
How to Understand the Image of a Black Hole | Veritasium
We are about to see the first image of a black hole, the supermassive black hole Sagittarius A* at the center of the Milky Way galaxy. But what is that image really showing us? This is an awesome paper on the topic by J.P. Luminet: Image of a spherical black hole with thin accretion disk Astronomy and Astrophysics, vol. 75, no. 1-2, May 1979, p. 228-235 https://ve42.co/luminet
The first picture of a black hole opens a new era of astrophysics
This is what a black hole looks like.
A world-spanning network of telescopes called the Event Horizon Telescope zoomed in on the supermassive monster in the galaxy M87 to create this first-ever picture of a black hole.
“We have seen what we thought was unseeable. We have seen and taken a picture of a black hole,” Sheperd Doeleman, EHT Director and astrophysicist at the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass., said April 10 in Washington, D.C., at one of seven concurrent news conferences. The results were also published in six papers in the Astrophysical Journal Letters.
“We’ve been studying black holes so long, sometimes it’s easy to forget that none of us have actually seen one,” France Cordova, director of the National Science Foundation, said in the Washington, D.C., news conference. Seeing one “is a Herculean task,” she said.
That’s because black holes are notoriously hard to see. Their gravity is so extreme that nothing, not even light, can escape across the boundary at a black hole’s edge, known as the event horizon. But some black holes, especially supermassive ones dwelling in galaxies’ centers, stand out by voraciously accreting bright disks of gas and other material. The EHT image reveals the shadow of M87’s black hole on its accretion disk. Appearing as a fuzzy, asymmetrical ring, it unveils for the first time a dark abyss of one of the universe’s most mysterious objects.
“It’s been such a buildup,” Doeleman said. “It was just astonishment and wonder… to know that you’ve uncovered a part of the universe that was off limits to us.”
During the day, some of us are lucky enough to be able to look up and see a clear blue beautiful sky and ‘our’ radiant Sun. During the night, most of us can gaze into the night sky and see lots of little bright points, stars. When we look up and see what we call ‘our Sun’, it can be hard to imagine that what we see also looks like this:
Image above: False-colour image of our Sun. Photographed by: Atmospheric Imaging Assembly of NASA’s Solar Dynamics Observatory.
Most of you may look at this and instantly know that it’s a Star. However, there are a fair amount of people who don’t realize that our night sky is full of millions of Stars like this, smaller, bigger and some the same size. Some people don’t know that the Sun is actually a star. I’ve got to admit that the image above looks nothing like what I see with the naked eye when looking up into the Sky:
You’ve probably been told that staring directly at the Sun is bad for your eyes. However, we don’t have to have uncomfortable staring contests with the Stars to try and get them to give up their secrets! After years and years of research, scientists have managed to find out quite a bit about the oh-so-secretive Stars without losing a staring contest.
Firstly, stars go through the same process that we do in the sense that they are born, live and then die. The difference is that they do it far more dramatically and take a much longer time doing it. Depending on the mass of the Star, the lifetime can range from a few million years to trillions of years!
The birth:
Naturally, this is where the comparisons between humans and Stars have to stop. The birth place of a Star is a huge, cold cloud of gas and dust, nebulae/nebulas.
Image above: Chandra, Hubble, and Spitzer image NGC 1952
These clouds begin to shrink, a result of their own gravity. As a cloud begins to shrink it gets smaller and the cloud breaks up into clumps. Eventually, these clumps reach high enough temperatures and get so dense that nuclear reactions begin. When the temperature reaches about 10 million degrees Celsius, the clump becomes a new star, a protostar. A protostar is not very stable. In order to live on, the protostar will need to achieve and maintain equilibrium, a balance between gravity pulling atoms towards the center of the protostar and gas pressure pushing heat and light away from the center. When a star can no longer maintain this balance, it dies.
How do we “know” any of this?
Infrared observatories such as ESA’s Herschel space observatory (launched in May 2009) are able to detect the heat that comes from such stars that we are not able to see, and therefore give us the information we need to research further.
Image above: Artist’s impression of the Herschel Space Observatory
If the critical temperature in the core of a protostar is never reached, it ends up as a brown dwarf, never achieving “star status”. However, if the critical temperature in the core of a protostar is reached then nuclear fusion begins. It is no longer classified as a protostar. It’s defined as a Star in the moment that it begins fusing the hydrogen in the core into helium. Simply put, nuclear fusion is a nuclear reaction where two or more atomic nuclei collide at high speeds and form a new type of atomic nucleus, in this case hydrogen forms helium.
“When a star can no longer maintain this balance, it dies.”
At “Star Status”, Stars spend the majority of their lives fusing hydrogen. So what happens when the hydrogen fuel is gone? Well, the Stars fuse helium into carbon and after a while, into even heavier elements. Maintaining the balance between gravity and gas pressure becomes very hard. The Stars eventually start to collapse on themselves. Before the Star’s inevitable collapse, nuclear reactions outside of the core cause the dying Star to expand outwards and this is what we call the “Red Giant” phase. It really is as dramatic as it sounds.
How dramatic the death is, depends on the mass of the Star. Our Sun is expected to turn into a white dwarf Star. If a Star has a slightly larger mass than our Sun, it may undergo a supernova explosion and leave behind a neutron Star. If even larger, at least three times the mass of the Sun, the Star could even implode to form an infinite gravitational warp in space, a black hole!
Image above: Computer generated image of a Black Hole
Stars live the majority of their lives in a phase that we call the Main Sequence. Our Sun is currently in the main sequence. However, not all the Stars in the Universe are in the main sequence. When we peer into the night sky, we see history. Perhaps you have spotted a few red Stars in the night sky? There’s a chance that the Stars you saw were already dead when you saw them. Why? Well, these stars are so many light years away that it takes a very long time before the visible light reaches our eyes. When we look up, we are looking at what a Star used to look like X light years ago (X depending on how far away the Star is).
Some stars are only just beginning to form, others are in the Main Sequence and some have begun to die. Luckily for us, there is an amazing diagram, The Hertzsprung – Russell diagram that shows the relationships and differences between Stars:
If you look at the HR-Diagram, you can see many dots. Each dot represents a Star. The Universe has many Stars in it; hence there are many dots on the diagram.
The diagram shows the temperature of the Stars and the Star’s luminosity. The vertical axis represents the Stars luminosity. Luminosity is the amount of energy a Star radiates in one second, where every Star is compared to each other based upon our Sun. Our sun is in the yellow part of the main sequence, and therefore has luminosity 1, all other Stars are compared to ours in this sense.
The horizontal axis represents the Star’s surface temperature, in Kelvin. Here we have higher temperatures on the left and lower temperatures on the right. Usually we go from lower to higher; however, it’s more adequate to see that a star in the upper left corner of the diagram is both hot and bright. A star in the upper right corner of the diagram is both cold and bright, what kind of star would this be? Take a look at the diagram. Happy Star hunting!
Glowing in mostly purple and green colors, a newly discovered celestial phenomenon is sparking the interest of scientists, photographers and astronauts. The display was initially discovered by a group of citizen scientists who took pictures of the unusual lights and playfully named them “Steve.”
When scientists got involved and learned more about these purples and greens, they wanted to keep the name as an homage to its initial name and citizen science discoverers. Now it is STEVE, short for Strong Thermal Emission Velocity Enhancement.
STEVE occurs closer to the equator than where most aurora appear – for example, Southern Canada – in areas known as the sub-auroral zone. Because auroral activity in this zone is not well researched, studying STEVE will help scientists learn about the chemical and physical processes going on there. This helps us paint a better picture of how Earth’s magnetic fields function and interact with charged particles in space. Ultimately, scientists can use this information to better understand the space weather near Earth, which can interfere with satellites and communications signals.
Want to become a citizen scientist and help us learn more about STEVE? You can submit your photos to a citizen science project called Aurorasaurus, funded by NASA and the National Science Foundation. Aurorasaurus tracks appearances of auroras – and now STEVE – around the world through reports and photographs submitted via a mobile app and on aurorasaurus.org.
Here are six tips from what we have learned so far to help you spot STEVE:
1. STEVE is a very narrow arc, aligned East-West, and extends for hundreds or thousands of miles.
2. STEVE mostly emits light in purple hues. Sometimes the phenomenon is accompanied by a short-lived, rapidly evolving green picket fence structure (example below).
4.STEVE appears closer to the equator than where normal – often green – auroras appear. It appears approximately 5-10° further south in the Northern hemisphere. This means it could appear overhead at latitudes similar to Calgary, Canada. The phenomenon has been reported from the United Kingdom, Canada, Alaska, northern US states, and New Zealand.
5. STEVE has only been spotted so far in the presence of an aurora (but auroras often occur without STEVE). Scientists are investigating to learn more about how the two phenomena are connected.
6. STEVE may only appear in certain seasons. It was not observed from October 2016 to February 2017. It also was not seen from October 2017 to February 2018.
STEVE (and aurora) sightings can be reported at www.aurorasaurus.org or with the Aurorasaurus free mobile apps on Android and iOS. Anyone can sign up, receive alerts, and submit reports for free.
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NASA’s Juno spacecraft was a little more than one Earth diameter from Jupiter when it captured this mind-bending, color-enhanced view of the planet’s tumultuous atmosphere.
Jupiter completely fills the image, with only a hint of the terminator (where daylight fades to night) in the upper right corner, and no visible limb (the curved edge of the planet).
Juno took this image of colorful, turbulent clouds in Jupiter’s northern hemisphere on Dec. 16, 2017 at 9:43 a.m. PST (12:43 p.m. EST) from 8,292 miles (13,345 kilometers) above the tops of Jupiter’s clouds, at a latitude of 48.9 degrees.
The spatial scale in this image is 5.8 miles/pixel (9.3 kilometers/pixel).
Citizen scientists Gerald Eichstädt and Seán Doran processed this image using data from the JunoCam imager.
JunoCam’s raw images are available for the public to peruse and process into image products at:
NASA’s Parker Solar Probe will be the first-ever mission to “touch” the Sun. The spacecraft, about the size of a small car, will travel directly into the Sun’s atmosphere about 4 million miles from the surface.
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As always, prints of my artworks are available in my print shop at Artstation and at Displate.com
Fictional mission / Space That Never Was / Alternate timeline
Two cosmonauts conducting a spacewalk to replace damaged piece of equipment mounted on the outer hull of the Ambition 2 spacecraft.
Ambition 2 / Mars-Phobos
In the mid 80s, international cooperation between USSR, USA, Japan and a few European countries resulted in a follow-up to successful Ambition 1 mission from a few years earlier. This time the goal was to visit and explore one of Mars moons, Phobos, in hope to find a suitable place for a permanent base on its surface, which would be built by the crew of Ambition 3, mission that would launch in late 1980s.
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As always, prints of my artworks are available in my print shop at Artstationand at Displate.com
