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Astronomers obtained the most detailed anatomy chart of a monster galaxy located 12.4 billion light-years away. Using the Atacama Large Millimeter/submillimeter Array (ALMA), the team revealed that the molecular clouds in the galaxy are highly unstable, which leads to runaway star formation.
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Our analysis of the molecular gas mass per unit area suggests that the starburst disk is gravitationally unstable, which implies that the self-gravity of the gas is stronger than the differential rotation of the disk and the internal pressure due to stellar-radiation feedback. As a result of the gravitational instability in the disk, the molecular gas would be consumed by star formation on a timescale of 100 million years, which is comparable to gas depletion times in merging starburst galaxies.
Tadaki et al. (2018) The gravitationally unstable gas disk of a starburst galaxy 12 billion years ago*_: https://www.nature.com/articles/s41586-018-0443-1
[...]
Our analysis of the molecular gas mass per unit area suggests that the starburst disk is gravitationally unstable, which implies that the self-gravity of the gas is stronger than the differential rotation of the disk and the internal pressure due to stellar-radiation feedback. As a result of the gravitational instability in the disk, the molecular gas would be consumed by star formation on a timescale of 100 million years, which is comparable to gas depletion times in merging starburst galaxies.
Tadaki et al. (2018) The gravitationally unstable gas disk of a starburst galaxy 12 billion years ago*_: https://www.nature.com/articles/s41586-018-0443-1
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Why are the tallest peaks in the solar system found on one of its smallest worlds? Like any planet, how Mars looks outside is tied to what goes on inside. Dig into planetary formation in this 60-second video and by visiting mars.nasa.gov/insight.
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“As time goes on, the amount of mass lost by the Sun will increase, particularly as it enters the giant phase of its life. But even at this relatively steady rate, the growth of helium in the Sun’s core means that we will heat up here on planet Earth. After about 1-to-2 billion years, the Sun will be burning hot enough that Earth’s oceans will boil away entirely, making liquid water impossible on the surface of our planet. As the Sun gets lighter and lighter, it will counterintuitively get hotter and hotter. Our planet has already used up approximately three-quarters of the time we have where Earth is habitable. As the Sun continues to lose mass, humanity and all life on Earth approaches its inevitable fate. Let’s make these last billion-or-so years count.”
As the Sun burns through its nuclear fuel, it loses mass in not one, but two ways. Sure, in its core, it’s fusing hydrogen in a chain reaction into helium, with the reduction in mass corresponding to a gain in energy: the energy that powers the Sun and gives life to all the planets. But it also blows off particles, including electrons, protons, and atomic nuclei, in a phenomenon called the solar wind. Even though more massive stars burn hotter and brighter than less massive ones, the Sun, perhaps paradoxically, will increase in temperature and luminosity as it loses mass to these two processes. The Sun is getting lighter and lighter, and the problem of its increasing energy output will eventually destroy all life on Earth.
Here’s how fast the Sun is losing mass, and what this means for the inevitable fate of everything that could ever live here on Earth.
As the Sun burns through its nuclear fuel, it loses mass in not one, but two ways. Sure, in its core, it’s fusing hydrogen in a chain reaction into helium, with the reduction in mass corresponding to a gain in energy: the energy that powers the Sun and gives life to all the planets. But it also blows off particles, including electrons, protons, and atomic nuclei, in a phenomenon called the solar wind. Even though more massive stars burn hotter and brighter than less massive ones, the Sun, perhaps paradoxically, will increase in temperature and luminosity as it loses mass to these two processes. The Sun is getting lighter and lighter, and the problem of its increasing energy output will eventually destroy all life on Earth.
Here’s how fast the Sun is losing mass, and what this means for the inevitable fate of everything that could ever live here on Earth.
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How a NASA scientist looks in the depths of the Great Red Spot to find water on Jupiter - For centuries, scientists have worked to understand the makeup of Jupiter. It's no wonder: this mysterious planet is the biggest one in our solar system by far, and chemically, the closest relative to the Sun. Understanding Jupiter is a key to learning more about how our solar system formed, and even about how other solar systems develop.
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“I do not understand why a star’s metallicity has an impact on its size. Why? I am asking this because in one of your articles, you were saying that in the beginning of the universe, stars with mass almost 1000 [times] the sun’s mass probably existed because they were almost 100% hydrogen and helium.”
There’s a bit of a puzzle in the Universe: the stars we form today are about 40% the mass of the Sun, on average, and the most massive one we’ve ever discovered is about 260 times the mass of our Sun. In the very early Universe, however, before any other, prior generations of stars formed, we expect the average stellar mass will be 10 times the Sun’s mass, with the largest stars reaching upwards of 1000 solar masses. If the only difference is the amount of heavy elements, then why, if metals help with cooling and enable stars to form more easily, would the first stars be biased towards higher masses?
It seems counterintuitive, but science has the answer to it. And with the answer, we might just have the explanation for how those pesky quasars, AGNs, and supermassive black holes formed so fast!
There’s a bit of a puzzle in the Universe: the stars we form today are about 40% the mass of the Sun, on average, and the most massive one we’ve ever discovered is about 260 times the mass of our Sun. In the very early Universe, however, before any other, prior generations of stars formed, we expect the average stellar mass will be 10 times the Sun’s mass, with the largest stars reaching upwards of 1000 solar masses. If the only difference is the amount of heavy elements, then why, if metals help with cooling and enable stars to form more easily, would the first stars be biased towards higher masses?
It seems counterintuitive, but science has the answer to it. And with the answer, we might just have the explanation for how those pesky quasars, AGNs, and supermassive black holes formed so fast!
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