burn away tears of lifetimes fly away towards the stars

Known as a “protostar,” this hot core of the collapsing cloud will is a star in the making. As a cloud – which is mostly hydrogen – collapses, the material at its center begins to heat up. Over thousands to millions of years, gravity can cause denser pockets within a nebula to collapse under their own weight. Stars are born from vast clouds of gas and dust, known as nebulae, that are scattered throughout most galaxies. Sunlike stars are merely 6% of the population, and K dwarfs are at 13%. Red dwarfs make up the bulk of the Milky Way's population, about 73%.

The relative amount of harmful radiation (to life as we know it) that stars emit can be 80 to 500 times more intense for M dwarfs relative to our Sun, but only 5 to 25 times more intense for the orange K dwarfs. Meanwhile, our Sun only lasts for 10 billion years. K dwarf ages can range from 15 to 45 billion years. The longevity for red dwarf M stars can exceed 100 billion years. The habitable zones, potentially capable of hosting life-bearing planets, are wider for hotter stars. This infographic compares the characteristics of three classes of stars in our galaxy: Sunlike stars are classified as G-type stars stars less massive and cooler than our Sun are K dwarfs and even fainter and cooler stars are the reddish M dwarfs. Red dwarfs typically calm down after a few billion years, but their early outbursts could prohibit their planets from evolving to be more hospitable. Planets in the habitable zones of red dwarfs can be baked bone dry and have their atmospheres stripped away quite early in their lives. Planets in a red dwarf's comparatively narrow habitable zone, which is very close to the star, are exposed to extreme levels of X-ray and ultraviolet radiation, which can be hundreds of thousands of times more intense than what Earth receives from the Sun. The even more abundant star type called red dwarfs (also known as M dwarf stars) have even longer lifetimes. And, for every star like our Sun, there are three times as many orange dwarfs in the Milky Way. This opens up a vast timescape for biological evolution to pursue an infinity of experiments for yielding robust life forms. They can burn steadily for tens of billions of years. Therefore, stars slightly cooler than our Sun – called orange dwarfs – are considered better for advanced life. Earth will become uninhabitable for higher forms of life in a little over 1 billion years, as the Sun grows warmer and dries our planet.

Complex organisms arose on Earth only 500 million years ago, and modern humans have been here for only 200,000 years – the blink of an eye on cosmological timescales. They come in a wide range of sizes and characteristics. Statistically, there should be more than 100 billion planets in our Milky Way galaxy. (For this reason, a star's habitable zone is often referred to informally as its 'Goldilocks zone.') This is the area around a star where conditions are just right, neither too hot nor too cold for liquid water to exist on a planet’s surface. Kornmesser, and NASAĭifferent star types have different habitable zones. Much more massive and brighter than our Sun, they would have blazed in the inky void of the newborn universe. Unlike the stars of today – like our Sun (which contains heavier elements such as oxygen, nitrogen, carbon, and iron) – Population III stars would have been solely made of the few primordial elements forged in the big bang. The very first stars born after the big bang, which astronomers call 'Population III' stars, are elusive, having yet to be definitively detected. This artist's impression represents the early universe.

Burn away tears of lifetimes fly away towards the stars