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A Mesmerizing Model of Monster Black Holes

Just about every galaxy the size of our Milky Way (or bigger) has a supermassive black hole at its center. These objects are ginormous — hundreds of thousands to billions of times the mass of the Sun! Now, we know galaxies merge from time to time, so it follows that some of their black holes should combine too. But we haven’t seen a collision like that yet, and we don’t know exactly what it would look like. 

A new simulation created on the Blue Waters supercomputer — which can do 13 quadrillion calculations per second, 3 million times faster than the average laptop — is helping scientists understand what kind of light would be produced by the gas around these systems as they spiral toward a merger.

The new simulation shows most of the light produced around these two black holes is UV or X-ray light. We can’t see those wavelengths with our own eyes, but many telescopes can. Models like this could tell the scientists what to look for. 

You may have spotted the blank circular region between the two black holes. No, that’s not a third black hole. It’s a spot that wasn’t modeled in this version of the simulation. Future models will include the glowing gas passing between the black holes in that region, but the researchers need more processing power. The current version already required 46 days!

The supermassive black holes have some pretty nifty effects on the light created by the gas in the system. If you view the simulation from the side, you can see that their gravity bends light like a lens. When the black holes are lined up, you even get a double lens!

But what would the view be like from between two black holes? In the 360-degree video above, the system’s gas has been removed and the Gaia star catalog has been added to the background. If you watch the video in the YouTube app on your phone, you can moved the screen around to explore this extreme vista. Learn more about the new simulation here. 

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Emily Thomas

Was Earth Born With Life On It?

“By finding graphite deposits in zircons that are 4.1 billion years old, graphite deposits that show this carbon-12 enhancement, we now have evidence that life on Earth goes back at least 90% of Earth’s history, and possibly even longer! After all, finding the remnants of organic matter in a certain location means the organic matter is at least as old as the location it’s buried in, but it could still be even older. This is so early that it might make you think that perhaps this life didn’t originate here on Earth, but that Earth was born with life. And this could really, truly be the case.”

How old is life on Earth? If all you had to go on was the fossil record, you’d run into severe trouble once you went back more than one or two billion years, as all your rock would have metamorphosed, making examination and identification of fossils impossible. But recently, we’ve discovered another method: to measure the isotopic content of carbon deposits in ancient rock formations. The carbon-12 to carbon-13 ratio is a surefire signature of life, and tells us that life on Earth goes back at least 4.1 billion years: 90% of the age of our planet. Could this be the hint we’ve needed to conclude that life on Earth actually predates the Earth itself? It’s not quite certain, but the beauty of science is we can always test it and find out! Here’s how.

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Cosmic Alphabet Soup: Classifying Stars

If you’ve spent much time stargazing, you may have noticed that while most stars look white, some are reddish or bluish. Their colors are more than just pretty – they tell us how hot the stars are. Studying their light in greater detail can tell us even more about what they’re like, including whether they have planets. Two women, Williamina Fleming and Annie Jump Cannon, created the system for classifying stars that we use today, and we’re building on their work to map out the universe.

By splitting starlight into spectra – detailed color patterns that often feature lots of dark lines – using a prism, astronomers can figure out a star’s temperature, how long it will burn, how massive it is, and even how big its habitable zone is. Our Sun’s spectrum looks like this:

Astronomers use spectra to categorize stars. Starting at the hottest and most massive, the star classes are O, B, A, F, G (like our Sun), K, M. Sounds like cosmic alphabet soup! But the letters aren’t just random – they largely stem from the work of two famous female astronomers.

Williamina Fleming, who worked as one of the famous “human computers” at the Harvard College Observatory starting in 1879, came up with a way to classify stars into 17 different types (categorized alphabetically A-Q) based on how strong the dark lines in their spectra were. She eventually classified more than 10,000 stars and discovered hundreds of cosmic objects!

That was back before they knew what caused the dark lines in spectra. Soon astronomers discovered that they’re linked to a star’s temperature. Using this newfound knowledge, Annie Jump Cannon – one of Fleming’s protégés – rearranged and simplified stellar classification to include just seven categories (O, B, A, F, G, K, M), ordered from highest to lowest temperature. She also classified more than 350,000 stars!

Type O stars are both the hottest and most massive in the new classification system. These giants can be a thousand times bigger than the Sun! Their lifespans are also around 1,000 times shorter than our Sun’s. They burn through their fuel so fast that they only live for around 10 million years. That’s part of the reason they only make up a tiny fraction of all the stars in the galaxy – they don’t stick around for very long.

As we move down the list from O to M, stars become progressively smaller, cooler, redder, and more common. Their habitable zones also shrink because the stars aren’t putting out as much energy. The plus side is that the tiniest stars can live for a really long time – around 100 billion years – because they burn through their fuel so slowly.

Astronomers can also learn about exoplanets – worlds that orbit other stars – by studying starlight. When a planet crosses in front of its host star, different kinds of molecules in the planet’s atmosphere absorb certain wavelengths of light.

By spreading the star’s light into a spectrum, astronomers can see which wavelengths have been absorbed to determine the exoplanet atmosphere’s chemical makeup. Our James Webb Space Telescope will use this method to try to find and study atmospheres around Earth-sized exoplanets – something that has never been done before.

Our upcoming Nancy Grace Roman Space Telescope will study the spectra from entire galaxies to build a 3D map of the cosmos. As light travels through our expanding universe, it stretches and its spectral lines shift toward longer, redder wavelengths. The longer light travels before reaching us, the redder it becomes. Roman will be able to see so far back that we could glimpse some of the first stars and galaxies that ever formed.

Learn more about how Roman will study the cosmos in our other posts:

Roman’s Family Portrait of Millions of Galaxies

New Rose-Colored Glasses for Roman

How Gravity Warps Light

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The diversity of worlds in our solar system (climate and geology)…

The Great Red Spot is a persistent high-pressure region in the atmosphere of Jupiter, producing an anticyclonic storm 22° south of the planet’s equator. It has been continuously observed for 188 years, since 1830. Earlier observations from 1665 to 1713 are believed to be of the same storm; if this is correct, it has existed for at least 350 years. Such storms are not uncommon within the turbulent atmospheres of gas giants.

With over 400 active volcanoes, Io is the most geologically active object in the Solar System. This extreme geologic activity is the result of tidal heating from friction generated within Io’s interior as it is pulled between Jupiter and the other Galilean satellites—Europa, Ganymede and Callisto.

Europa has the smoothest surface of any known solid object in the Solar System. The apparent youth and smoothness of the surface have led to the hypothesis that a water ocean exists beneath it, which could conceivably harbor extraterrestrial life.

Neptune, the eighth and farthest planet from the sun, has the strongest winds in the solar system. At high altitudes speeds can exceed 1,100 mph. That is 1.5 times faster than the speed of sound. In 1989, NASA’s Voyager 2 spacecraft made the first and only close-up observations of Neptune.

Ganymede  is the largest and most massive moon of Jupiter and in the Solar System. Possessing a metallic core, it has the lowest moment of inertia factor of any solid body in the Solar System and is the only moon known to have a magnetic field. (Sounds of Ganymede’s magnetosphere).

Saturn’s hexagon is a persisting hexagonal cloud pattern around the north pole of Saturn, located at about 78°N. The sides of the hexagon are about 13,800 km (8,600 mi) long, which is more than the diameter of Earth (about 12,700 km (7,900 mi)).

Miranda’s surface has patchwork regions of broken terrain indicating intense geological activity in Miranda’s past, and is criss-crossed by huge canyons. It also has the largest known cliff in the Solar System, Verona Rupes, which has a height of over 5 km (3.1 mi). 

Some of Miranda’s terrain is possibly less than 100 million years old based on crater counts, which suggests that Miranda may still be geologically active today.

Enceladus is the sixth-largest moon of Saturn. It is about 500 kilometers (310 mi) in diameter, about a tenth of that of Saturn’s largest moon, Titan.  Evidence of liquid water on Enceladus began to accumulate in 2005, when scientists observed plumes containing water vapor spewing from its south polar surface, with jets moving 250 kg of water vapor every second at up to 2,189 km/h (1,360 mph) into space.

Titan is the largest moon of Saturn. It is the only moon known to have a dense atmosphere, and the only object in space, other than Earth, where clear evidence of stable bodies of surface liquid has been found.

Triton is one of the few moons in the Solar System known to be geologically active (the others being Jupiter’s Io and Europa, and Saturn’s Enceladus and Titan). As a consequence, its surface is relatively young with few obvious impact craters, and a complex geological history revealed in intricate cryovolcanic and tectonic terrains. Part of its surface has geysers erupting sublimated nitrogen gas, contributing to a tenuous nitrogen atmosphere less than 1/70,000 the pressure of Earth’s atmosphere at sea level.

source: wikipedia~

image credit: data and images from NASA