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The Nearest Supernova Of Our Lifetime Turns 30, And Still Shines

“The supernova light brightened and then dimmed, but the surrounding gas, blown off from the supergiant, remains illuminated by radiation. As shockwaves from the explosion move outwards, they collide with interstellar material, producing brightening rings of material.”

In February of 1987, the first light from a supernova some 168,000 light years away was observed on Earth. It became the closest supernova to be observed since the invention of the telescope. As a result, it’s taught us more about massive star death, ejecta and supernova remnant evolution than any other object in the Universe. Illuminated outer rings showcase ejection events that occurred prior to the final death of the star; continued brightening teach us the rate of expansion of the supernova remnant; the lack of a neutron star at the core teaches us about the power of dust to obscure even radio light from this object. Perhaps most interestingly, neutrinos were observed from this supernova, arriving nearly three hours before the light did, confirming that they move through a star unimpeded, unlike light.

Come get the full story in some amazing pictures, videos and under 200 words of text on today’s Mostly Mute Monday!

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THE DAWN OF A NEW ERA FOR SUPERNOVA 1987A

Three decades ago, astronomers spotted one of the brightest exploding stars in more than 400 years. The titanic supernova, called Supernova 1987A (SN 1987A), blazed with the power of 100 million suns for several months following its discovery on Feb. 23, 1987.

Since that first sighting, SN 1987A has continued to fascinate astronomers with its spectacular light show. Located in the nearby Large Magellanic Cloud, it is the nearest supernova explosion observed in hundreds of years and the best opportunity yet for astronomers to study the phases before, during, and after the death of a star.

To commemorate the 30th anniversary of SN 1987A, new images, time-lapse movies, a data-based animation based on work led by Salvatore Orlando at INAF-Osservatorio Astronomico di Palermo, Italy, and a three-dimensional model are being released. By combining data from NASA’s Hubble Space Telescope and Chandra X-ray Observatory, as well as the international Atacama Large Millimeter/submillimeter Array (ALMA), astronomers – and the public – can explore SN 1987A like never before.

Hubble has repeatedly observed SN 1987A since 1990, accumulating hundreds of images, and Chandra began observing SN 1987A shortly after its deployment in 1999. ALMA, a powerful array of 66 antennas, has been gathering high-resolution millimeter and submillimeter data on SN 1987A since its inception.

“The 30 years’ worth of observations of SN 1987A are important because they provide insight into the last stages of stellar evolution,” said Robert Kirshner of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass., and the Gordon and Betty Moore Foundation in Palo Alto, Calif.

The latest data from these powerful telescopes indicate that SN 1987A has passed an important threshold. The supernova shock wave is moving beyond the dense ring of gas produced late in the life of the pre-supernova star when a fast outflow or wind from the star collided with a slower wind generated in an earlier red giant phase of the star’s evolution. What lies beyond the ring is poorly known at present, and depends on the details of the evolution of the star when it was a red giant.

“The details of this transition will give astronomers a better understanding of the life of the doomed star, and how it ended,” said Kari Frank of Penn State University, who led the latest Chandra study of SN 1987A.

Supernovas such as SN 1987A can stir up the surrounding gas and trigger the formation of new stars and planets. The gas from which these stars and planets form will be enriched with elements such as carbon, nitrogen, oxygen, and iron, which are the basic components of all known life. These elements are forged inside the pre-supernova star and during the supernova explosion itself, and then dispersed into their host galaxy by expanding supernova remnants. Continued studies of SN 1987A should give unique insight into the early stages of this dispersal.

“A supernova remnant cools quickly, so within a few years the heavy elements formed in the star can form molecules and condense into dust, turning the remnant into a veritable dust factory,” said Remy Indebetouw of the National Radio Astronomy Observatory in Charlottesville, Va. “ALMA is now able to see this newly formed dust directly, and ongoing studies will help us understand how it forms and how supernovas seed interstellar space with the raw material for new planetary systems.”

Some highlights from studies involving these telescopes include the following:

* Hubble studies have revealed that the dense ring of gas around the supernova is glowing in optical light, and has a diameter of about a light-year. The ring was there at least 20,000 years before the star exploded. A flash of ultraviolet light from the explosion energized the gas in the ring, making it glow for decades.

* The central structure visible inside the ring in the Hubble image has now grown to roughly half a light-year across. Most noticeable are two blobs of debris in the center of the supernova remnant racing away from each other at roughly 20 million miles an hour.

* From 1999 until 2013, Chandra data showed an expanding ring of X-ray emission that had been steadily getting brighter. The blast wave from the original explosion has been bursting through and heating the ring of gas surrounding the supernova, producing X-ray emission.

* In the past few years, the ring has stopped getting brighter in X-rays. From about February 2013 until the last Chandra observation analyzed in September 2015 the total amount of low-energy X-rays has remained constant. Also, the bottom left part of the ring has started to fade. These changes provide evidence that the explosion’s blast wave has moved beyond the ring into a region with less dense gas. This represents the end of an era for SN 1987A.

* Beginning in 2012, astronomers used ALMA to observe the glowing remains of the supernova, studying how the remnant is actually forging vast amounts of new dust from the new elements created in the progenitor star. A portion of this dust will make its way into interstellar space and may become the building blocks of future stars and planets in another system. These observations also suggest that dust in the early universe likely formed from similar supernova explosions.

Astronomers also are still looking for evidence of a black hole or a neutron star left behind by the blast. They observed a flash of neutrinos from the star just as it erupted. This detection makes astronomers quite certain a compact object formed as the center of the star collapsed – either a neutron star or a black hole – but no telescope has uncovered any evidence for one yet.

More Earth-like than moon-like

New mars research shows evidence of a complex mantle beneath the Elysium volcanic province


Mars’ mantle may be more complicated than previously thought. In a new study published today in the Nature-affiliated journal Scientific Reports, researchers at LSU document geochemical changes over time in the lava flows of Elysium, a major martian volcanic province.

LSU Geology and Geophysics graduate researcher David Susko led the study with colleagues at LSU including his advisor Suniti Karunatillake, the University of Rahuna in Sri Lanka, the SETI Institute, Georgia Institute of Technology, NASA Ames, and the Institut de Recherche en Astrophysique et Planétologie in France.

They found that the unusual chemistry of lava flows around Elysium is consistent with primary magmatic processes, such as a heterogeneous mantle beneath Mars’ surface or the weight of the overlying volcanic mountain causing different layers of the mantle to melt at different temperatures as they rise to the surface over time.

Elysium is a giant volcanic complex on Mars, the second largest behind Olympic Mons. For scale, it rises to twice the height of Earth’s Mount Everest, or approximately 16 kilometers. Geologically, however, Elysium is more like Earth’s Tibesti Mountains in Chad, the Emi Koussi in particular, than Everest. This comparison is based on images of the region from the Mars Orbiter Camera, or MOC, aboard the Mars Global Surveyor, or MGS, Mission.

Elysium is also unique among martian volcanoes. It’s isolated in the northern lowlands of the planet, whereas most other volcanic complexes on Mars cluster in the ancient southern highlands. Elysium also has patches of lava flows that are remarkably young for a planet often considered geologically silent.

“Most of the volcanic features we look at on Mars are in the range of 3-4 billion years old,” Susko said. “There are some patches of lava flows on Elysium that we estimate to be 3-4 million years old, so three orders of magnitude younger. In geologic timescales, 3 million years ago is like yesterday.”

In fact, Elysium’s volcanoes hypothetically could still erupt, Susko said, although further research is needed to confirm this. “At least, we can’t yet rule out active volcanoes on Mars,” Susko said. “Which is very exciting.”

Susko’s work in particular reveals that the composition of volcanoes on Mars may evolve over their eruptive history. In earlier research led by Karunatillake, assistant professor in LSU’s Department of Geology and Geophysics, researchers in LSU’s Planetary Science Lab, or PSL, found that particular regions of Elysium and the surrounding shallow subsurface of Mars are geochemically anomalous, strange even relative to other volcanic regions on Mars. They are depleted in the radioactive elements thorium and potassium. Elysium is one of only two igneous provinces on Mars where researchers have found such low levels of these elements so far.

“Because thorium and potassium are radioactive, they are some of the most reliable geochemical signatures that we have on Mars,” Susko said. “They act like beacons emitting their own gamma photons. These elements also often couple in volcanic settings on Earth.”

In their new paper, Susko and colleagues started to piece together the geologic history of Elysium, an expansive volcanic region on Mars characterized by strange chemistry. They sought to uncover why some of Elysium’s lava flows are so geochemically unusual, or why they have such low levels of thorium and potassium. Is it because, as other researchers have suspected, glaciers located in this region long ago altered the surface chemistry through aqueous processes? Or is it because these lava flows arose from different parts of Mars’ mantle than other volcanic eruptions on Mars?

Perhaps the mantle has changed over time, meaning that more recent volcanic eruption flows differ chemically from older ones. If so, Susko could use Elysium’s geochemical properties to study how Mars’ bulk mantle has evolved over geologic time, with important insights for future missions to Mars. Understanding the evolutionary history of Mars’ mantle could help researchers gain a better understanding of what kinds of valuable ores and other materials could be found in the crust, as well as whether volcanic hazards could unexpectedly threaten human missions to Mars in the near future. Mars’ mantle likely has a very different history than Earth’s mantle because the plate tectonics on Earth are absent on Mars as far as researchers know. The history of the bulk interior of the red planet also remains a mystery.

Susko and colleagues at LSU analyzed geochemical and surface morphology data from Elysium using instruments on board NASA’s Mars Odyssey Orbiter (2001) and Mars Reconnaissance Orbiter (2006). They had to account for the dust that blankets Mars’ surface in the aftermath of strong dust storms, to make sure that the shallow subsurface chemistry actually reflected Elysium’s igneous material and not the overlying dust.

Through crater counting, the researchers found differences in age between the northwest and the southeast regions of Elysium – about 850 million years of difference. They also found that the younger southeast regions are geochemically different from the older regions, and that these differences in fact relate to igneous processes, not secondary processes like the interaction of water or ice with the surface of Elysium in the past.

“We determined that while there might have been water in this area in the past, the geochemical properties in the top meter throughout this volcanic province are indicative of igneous processes,” Susko said. “We think levels of thorium and potassium here were depleted over time because of volcanic eruptions over billions of years. The radioactive elements were the first to go in the early eruptions. We are seeing changes in the mantle chemistry over time.”

“Long-lived volcanic systems with changing magma compositions are common on Earth, but an emerging story on Mars,” said James Wray, study co-author and associate professor in the School of Earth and Atmospheric Sciences at Georgia Tech.

Wray led a 2013 study that showed evidence for magma evolution at a different martian volcano, Syrtis Major, in the form of unusual minerals. But such minerals could be originating at the surface of Mars, and are visible only on rare dust-free volcanoes.

“At Elysium we are truly seeing the bulk chemistry change over time, using a technique that could potentially unlock the magmatic history of many more regions across Mars,” he said.

Susko speculates that the very weight of Elysium’s lava flows, which make up a volcanic province six times higher and almost four times wider than its morphological sister on Earth, Emi Koussi, has caused different depths of Mars’ mantle to melt at different temperatures. In different regions of Elysium, lava flows may have come from different parts of the mantle.

Seeing chemical differences in different regions of Elysium, Susko and colleagues concluded that Mars’ mantle might be heterogeneous, with different compositions in different areas, or that it may be stratified beneath Elysium.

Overall, Susko’s findings indicate that Mars is a much more geologically complex body than originally thought, perhaps due to various loading effects on the mantle caused by the weight of giant volcanoes.

“It’s more Earth-like than moon-like,” Susko said. “The moon is cut and dry. It often lacks the secondary minerals that occur on Earth due to weathering and igneous-water interactions. For decades, that’s also how we envisioned Mars, as a lifeless rock, full of craters with a number of long inactive volcanoes. We had a very simple view of the red planet. But the more we look at Mars, the less moon-like it becomes. We’re discovering more variety in rock types and geochemical compositions, as seen across the Curiosity Rover’s traverse in Gale Crater, and more potential for viable resource utilization and capacity to sustain a human population on Mars. It’s much easier to survive on a complex planetary body bearing the mineral products of complex geology than on a simpler body like the moon or asteroids.”

Susko plans to continue clarifying the geologic processes that cause the strange chemistry found around Elysium. In the future, he will study these chemical anomalies through computational simulations, to determine if recreating the pressures in Mars’ mantle caused by the weight of giant volcanoes could affect mantle melting to yield the type of chemistry observed within Elysium.

Vera Rubin, the groundbreaking astrophysicist who discovered evidence of dark matter, died Sunday night at the age of 88, the Carnegie Institution confirms.

Rubin did much of her revelatory work at Carnegie. The organization’s president calls her a “national treasure.”

In the 1960s and 1970s, Rubin was working with astronomer Kent Ford, studying the behavior of spiral galaxies, when they discovered something entirely unexpected — the stars at the outside of the galaxy were moving as fast as the ones in the middle, which didn’t fit with Newtonian gravitational theory.

The explanation: Dark matter.

Adam Frank, an astrophysicist who writes for NPR’s 13.7 blog, described dark matter by comparing it to a ghost in a horror movie. You can’t see it, he writes — “but you know it’s with you because it messes with the things you can see.”

Adam continued:

“It was Vera Rubin’s famous work in the 1970s that showed pretty much all spiral galaxies were spinning way too fast to be accounted for by the gravitational pull of the their ‘luminous’ matter (the stuff we see in a telescope). Rubin and others reasoned there had to be a giant sphere of invisible stuff surrounding the stars in these galaxies, tugging on them and speeding up their orbits around the galaxy’s center.”

Vera Rubin, Who Confirmed Existence Of Dark Matter, Dies At 88

telegraph.co.uk
Nasa discover new solar system with ‘best chance yet of alien life’ yet - LIVE
Life may have evolved on at least three planets in a newly discovered solar system just 39 light years from Earth, NASA has announced.

⚠️️ BREAKTHROUGH  ⚠️️ 

Nasa is currently livestreaming a conference about the discovery of a new solar system !

“Astronomers have detected no less than seven Earth-sized worlds orbiting a cool dwarf star known as TRAPPIST-1.The six inner planets lie in a temperate zone where surface temperatures range from zero to 100C.

Of these, at least three are thought to be capable of having oceans, increasing the likelihood of life.

No other star system known contains such a large number of Earth-sized and probably rocky planets.”

I AM SO EXCITED

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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.

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!!