Cassini WAC RGB view of crescent Saturn with Titan in the distance.
(NASA) A mysterious, squid-like apparition, this nebula is very faint, but also very large in planet Earth’s sky. In the mosaic image, composed with narrowband data from the 2.5 meter Isaac Newton Telescope, it spans some 2.5 full moons toward the constellation Cepheus. Recently discovered by French astro-imager Nicolas Outters, the remarkable nebula’s bipolar shape and emission are consistent with it being a planetary nebula, the gaseous shroud of a dying sun-like star, but its actual distance and origin are unknown. A new investigation suggests Ou4 really lies within the emission region SH2-129 some 2,300 light-years away. Consistent with that scenario, the cosmic squid would represent a spectacular outflow of material driven by a triple system of hot, massive stars, cataloged as HR8119, seen near the center of the nebula. If so, this truly giant squid nebula would physically be nearly 50 light-years across.
Scientists at MIT have developed a new simulation that traces 13 billion years of cosmic evolution. They start the simulation shortly after the big bang with a region of space much smaller than the universe (a mere 350 million light years across). Still, it’s big enough to follow the forces that helped create the galaxies we see today, and correctly predict the gas and metal content of those galaxies.
At first, we see dark matter clustering due to the force of gravity (first two GIFs). Then we see visible matter — blue for cool clouds of gas where galaxies form, red for more violent explosive galaxies (second two GIFs).
Super massive blackholes form, superheating the material around them, causing bright white explosions that enrich the space between galaxies with warm but sparse gas (fifth GIF).
Different elements (represented by different colors in the sixth GIF) are spread through the universe.
We arrive at a distribution of dark matter that looks similar to the one we see in our universe today (seventh GIF).
The simulation is so complex it would take two thousand years to render on a single desktop. And it’s kinda beautiful.
Image Credit: MIT and Nature Video
3D Supernova Simulation
- Title: Magnetorotational Core-Collapse Supernovae in Three Dimensions
- Authors: P. Mösta, S. Richers, C. D. Ott, R. Haas, A. L. Piro, K. Boydstun, E. Abdikamalov, C. Reisswig, E. Schnetter
When a massive star reaches the end of its life, it collapses into a supernova. This results in a large amount of energy being released. The majority of this energy, ~99%, is released in the form of neutrinos, and the remaining 1% is the energy that drives a supernova. A large explosion like this is a core-collapse supernova.
Astronomers can see the results of a supernova, but what drives a massive star to undergo this dramatic process and create such a large explosion is not fully understood.
In an attempt to better understand what leads to a core-collapse supernova, astrophysicists created 3D simulations of rapidly rotating, strongly magnetized, core-collapse supernovae. When comparing their results with 2D simulations having the same initial conditions, the astrophysicists found that the 3D and 2D core-collapse supernovae were fundamentally different.
In 2D, bipolar jets are produced, but in 3D, a magnetohydrodynamic instability causes two asymmetric polar lobes to form instead. This instability occurs in a shorter time scale than what is needed for the jets to develop.
If the lobes expand outward, there will be accretion of matter and the star will eventually collapse to form a black hole, resulting in a gamma ray burst and a core-collapse supernova.
More videos, images, and resources are available on the researcher’s website.
Video: A time-evolution, volume rendering of the thermal pressure over the magnetic pressure (Pgas/Pmag) in a rapidly rotating,strongly magnetized massive star undergoing core-collapse. (source)
A Dot Does a Lot
Meet one of the newest celestial bodies to be discovered: rogue planets, worlds that hurtle around the galaxy without any parent star. Caitlin Hofmeister explains how we found them, and where we think they might have come from.
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What is the Multiverse, and why do we think it exists?
[…] Our observable Universe caps out at about 92 billion light-years in diameter, less than a thousand times as large in all directions as our previous scale. It contains some 10^80 atoms, clumped together in maybe a trillion galaxies, each with typically hundreds of billions of stars. But one of the most remarkable things about the Big Bang is that all of this, some 13.8 billion years ago, was once contained in a very small region of space, a region much smaller than our Solar System is today!
The thing that you might immediately wonder is whether there’s more Universe beyond the part that’s observable to us today, and — if so — how far does it go on? And what does it look like? And what are the physical laws in that part of the Universe?
Based on our observations of everything we’ve been able to see, from stars to galaxies to the leftover glow from the Big Bang to the matter in intergalactic space, we can learn some amazing things.