Category: supernova

Sorry Science Fans, Discovering A 70-Solar-Mass Black Hole Is Routine, Not Impossible

“Astronomers aren’t perplexed by this object (or similar ones to it) at all, but rather are fascinated with uncovering the details of how they formed and how common they truly are. The mystery isn’t why these objects exist at all, but rather how the Universe makes them in the abundances we observe. We don’t falsely generate excitement by spreading misinformation that diminishes our knowledge and ideas prior to this discovery.

In science, the ultimate rush comes from discovering something that furthers our understanding of the Universe within the context of everything else we know. May we never be tempted to pretend anything else is the case.”

Did you hear about this “impossible” black hole that “perplexes” astronomers and “defies” theory? If you followed the news cycle last week, that’s probably what you’ve heard. But the truth is far more interesting, and includes facts like:

-this is the fourth black hole we’ve found like it, not the first,
-there are two other ways to make black holes that would explain this object in addition to the one way that can’t,
-and that we’ve seen each and every one of the steps necessary to make a black hole like this,
-but that finding this black hole with this particular method really is revolutionary?

As always, the real science is far more interesting than the mangled hype you’ve seen before. This black hole doesn’t defy theory, but sure does teach us a lot. Come get the real story today.

Physicists Used Einstein’s Relativity To Successfully Predict A Supernova Explosion

“When the lens and a background source align in a particular fashion, quadruple images will result. With slightly different light-travel paths, the brightness and arrival time of each image is unique. In November 2014, a quadruply-lensed supernova was observed, showcasing exactly this type of alignment. Although a single galaxy caused the quadruple image, that galaxy was part of a huge galaxy cluster, exhibiting its own strong lensing effects. Elsewhere in the cluster, two additional images of the same galaxy also appear.”

We normally think of light traveling in a straight line, but that’s only true if your space is flat. In the real Universe, mass and matter not only exist, but clump together into massive structures like galaxies, quasars, and galaxy clusters. When a background source of light passes through these foreground masses, the light can get bent and distorted into multiple images that are magnified and arrive at slightly different times. If an event occurs in one such image, we can predict, based on General Relativity, cluster dynamics, and dark matter, when that event will appear in the other images.

In November 2014, we discovered a multiply-lensed supernova, and predicted where and when it would appear in the other images. Einstein and dark matter both win again!

These Are The 6 Different Ways To Make A Supernova

“Yet, if you cross a certain mass threshold, you overcome that quantum barrier, and that triggers a runaway fusion reaction, destroying the white dwarfs and leading to a different class of supernova: a thermal runaway supernova.

So, we’ve got core collapse supernovae and thermal runaway supernovae. Does that mean that there are only two classes?

Hardly. There’s more than one way to make both a thermal runaway and a core collapse supernova, and each mechanism or method has properties that are wholly unique to it. Here are the six ways to make a supernova, starting with the least-massive trigger and going up from there.”

So, you’ve got a star, and you want to trigger a supernova with it? Great! Every star that ever gets made in the Universe has the possibility of going supernova. If your star is born with more than about 8 solar masses, it’s practically an inevitability that a supernova will ensue, and that it will be a core-collapse supernova at that. But there are four independent ways to make that happen, and only one of them is the conventional way you probably think about it. If your star has less than 8 solar masses, though, it ends its life in a white dwarf, but that’s not necessarily the end. White dwarfs can gain enough mass, through two different known mechanisms, to someday go supernova as well.

There are six different ways to make a supernova, and each one is spectacular. Which one is your favorite?

How A Failed Nuclear Experiment Accidentally Gave Birth To Neutrino Astronomy

“The scientific importance of this result cannot be overstated. It marked the birth of neutrino astronomy, just as the first direct detection of gravitational waves from merging black holes marked the birth of gravitational wave astronomy. It was the birth of multi-messenger astronomy, marking the first time that the same object had been observed in both electromagnetic radiation (light) and via another method (neutrinos).

It showed us the potential of using large, underground tanks to detect cosmic events. And it causes us to hope that, someday, we might make the ultimate observation: an event where light, neutrinos, and gravitational waves all come together to teach us all about the workings of the objects in our Universe.”

When you build an experiment to look for an effect you’ve never seen before, it’s an extremely risky endeavor. If what you’re expecting to find is actually there, the payoff is tremendous: like the LHC finding the Higgs. If there’s nothing to find, like the direct detection searches for WIMP dark matter, the null result can be viewed as a colossal (and expensive) failure. One such failure was the construction of an enormous, 3,000+ ton detector facility to look for proton decays. The proton, as you may have heard, is stable, so in that regard, the experiments looking for decays were wildly unsuccessful. But that same setup is extremely sensitive to neutrinos, and in 1987, we used a nucleon decay experiment to successfully find the first neutrinos from beyond the Milky Way!

Come get the story of KamiokaNDE, and learn how it went from being an unsuccessful nucleon decay experiment to the birth of multi-messenger astronomy!

The 7 Most Powerful Fireworks Shows In The Universe

“Forget mere chemical reactions; in space, matter-energy conversion creates unprecedentedly powerful explosive events.

Here are the 7 most powerful natural displays of cosmic fireworks.

7.) Type Ia supernova: when two white dwarf stars collide, they initiate a runaway fusion reaction, destroying both stellar remnants.”

Throughout the Universe, there are many beautiful displays of cosmic fireworks. Stars are born; galaxies collide; gas gets heated and expelled; stars and stellar remnants explode and die. We typically think of supernova events as the culmination of the brightest, most energetic things that can happen in the cosmos. But supernovae only fill up the bottom rungs on the list of the most powerful, natural fireworks shows that the Universe provides us with.

Which ones are the most energetic? Find out on this incredible start to your pre-4th-of-July Monday!

How Do The Most Massive Stars Die: Supernova, Hypernova, Or Direct Collapse?

“When we see a very massive star, it’s tempting to assume it will go supernova, and a black hole or neutron star will remain. But in reality, there are two other possible outcomes that have been observed, and happen quite often on a cosmic scale. Scientists are still working to understand when each of these events occurs and under what conditions, but they all happen. The next time you look at a star that’s many times the size and mass of our Sun, don’t think “supernova” as a foregone conclusion. There’s a lot of life left in these objects, and a lot of possibilities for their demise, too. We know our observable Universe started with a bang. For the most massive stars, we still aren’t certain whether they end with the ultimate bang, destroying themselves entirely, or the ultimate whimper, collapsing entirely into a gravitational abyss of nothingness.”

How do stars die? If you’re low in mass, you’ll burn through all your fuel and just contract down. If you’re mid-ranged, like our Sun, you’ll become a giant, blow off your outer layers, and then the remaining core will contract to a white dwarf. And the high-mass stars can take an even more spectacular path: going supernova to produce either a neutron star or a black hole at their core. But that’s not all a high-mass star can do. We’ve seen supernova impostors, hypernovae that are even more luminous than the brightest supernova, and direct collapse black holes, where no explosion or even ejecta exists from a star that used to be present and massive. The science behind them in incredible, and while there are still uncertainties in predicting a star’s fate, we’re learning more all the time.

Come get the fascinating physics behind how the most massive stars die. You might think “supernova” every time, but the Universe is far more intricate and complex than that!

Unfortunately observations made by the Spritzer telescope in 2007 indicate that “the pillars of creation” were destroyed in a supernova about 6000 years ago; but the light from the new nebula won’t reach us for approximately 1000 years.

The Pillars Of Creation Haven’t Been Destroyed, After All

“Moreover, the best evidence for changes comes at the base of the pillars, indicating an evaporation time on the order of between 100,000 and 1,000,000 years. The idea that the pillars have already been destroyed has been demonstrated not to be true. It’s one of the great hopes of science that any controversial claims will be laid to rest by more and better data, and this is one situation where that has paid off in spades. Not only has there not been a supernova that’s in the process of destroying the pillars, but the pillars themselves should be robust for a long time to come.”

In 1995, NASA’s Hubble Space Telescope observed the Eagle Nebula, identifying the now-iconic pillars of creation, where newborn stars are forming inside a gas-rich, dusty region of space. Outside of those pillars, thousands of stars shine brightly, working to boil the gas off, while inside, the radiation from newly-formed stars works to boil it away from the inside. In 2007, the Spitzer Space Telescope, observing in the infrared, suggested that these pillars were blown apart thousands of years ago by a supernova, and that the light hadn’t simply reached our eyes yet. This was controversial, however, and follow-up observations would be required to know for certain. Well, the data has come in, and guess what?

The pillars of creation haven’t been destroyed after all, as the supernova seems to never have occurred. Instead of ~1,000 years, we should have hundreds of thousands of years before the pillars disappear completely. Come get the full story.

The Earliest Galaxies Spin Just Like Our Milky Way, Defying Expectations

“As our data sets improve, we should begin to measure the internal motions of large numbers of galaxies like this, which will answer many questions and raise others. Do most/all galaxies at these early stages rotate in a whirlpool-like plane? Is there a variety and multiple sets of populations that exhibit different behaviors? What are the actual effects of gas infall, supernovae, and small-scale motions? What is the velocity profile of these rotation curves, and can they teach us anything about the interplay of radiation, normal matter, and dark matter?

While we hope to learn these answers, we can now ask these questions sensibly in the aftermath of having measured the movement and internal motions of a galaxy so far away. At least for the first two, they rotate very similarly to their much older cousins, a quite unexpected result. Thanks to ALMA, we’re taking those coveted next steps into the final frontier.”

It wasn’t supposed to be this way. When you form galaxies in the very young Universe, it’s supposed to be a chaotic, turbulent place. Sure, you have gravitation, pulling matter in and creating a pancake-like shape. But then you form stars, and everything goes haywire. Supernovae go off, gas falls in, protogalaxies merge and get swallowed, motions get stirred up, and turbulence should permeate the galaxy. It ought to take billions of years for them to quiet down into a Milky Way-like whirlpool. Well, for the first time, owing to ALMA and Renske Smit’s team, the internal motions of galaxies less than a billion years old were measured, and – surprise! – their movement is smooth and not chaotic at all.

They’re less than a billion years old. And, thanks to ALMA observing them, they might finally pave the way to understand how galaxies form altogether.


SN 2006gy: Possible Quark Nova

Supernovae (SN) usually occur when massive stars exhaust their fuel and collapse under their own gravity. In the case of SN 2006gy, however, a very different effect may have triggered the explosion. SN 2006gy and its host galaxy NGC 1260 are located in the Perseus Cluster of galaxies, part of the Pisces-Perseus Supercluster.

The SN 2006gy – discovered by Robert Quimby in 2006 August, has challenged our understanding of stellar evolution. SN 2006gy was 100 times more luminous than a typical SN and at the time the most energetic ever recorded. For almost a year it continued to radiate at a rate in which an ordinary SN could only sustain for at most a few days. The superluminous SN was too bright in visible light for Type-II supernovae produced by most massive stars, and it produced relatively few x-rays for Type Ia supernovae, which means SN 2006gy may have originated from an extremely massive star.

Massive stars with 130 – 250 solar masses produce high-energy gamma rays that can convert some of the energy into matter and anti-matter pairs (mostly electron-positron pairs). Instead of mass being converted to energy in the star’s core, energy is being converted to mass (nickel-56). The resulting drop in pressure causes the star to shed some of its outer layers in a large eruption, and collapse – earlier than expected during the luminous blue variable (LBV) phase. Pair instability supernovae are luminous enough but they seem to have a slow rise, and core collapse.


 However, there’s an alternative, more exotic explanation. Subsequent study of SN 2006gy suggests that it underwent a neutron star (NS) to quark-nova (QN) stage. A quark nova, is the explosion driven by phase transition of the core of a neutron star to the quark matter phase leading to the formation of a quark star (QS). The collision between material ejected through the QN explosion and the preceding stellar envelope could basically re-brighten the SN, which means it could radiate at higher levels for longer periods of time.

Check out the links below for more information:

X-ray: NASA/CXC/UC Berkeley/N.Smith et al.; IR: Lick/UC Berkeley/J.Bloom & C.Hansen