If a star formation is occurring within, a Giant Molecular Cloud is also called a stellar nursery. Giant molecular clouds have a lifespan of about 10 to 100 million years before they disperse, because of the heat and stellar winds caused by the star formations within them.
The Taurus Molecular Cloud (TMC) is a star-forming region located only about 450 light-years away from Earth in the northern constellation of Taurus (the Bull).
Molecular clouds are dense and compact regions throughout the Milky Way and other galaxies where gas and dust clump together. The Taurus Molecular Cloud contains numerous deeply embedded protostars with massive disks left over from stellar formation, T Tauri stars (very young low-mass stars, still in the process of gravitational contraction), Herbig-Haro objects (narrow jets of gas and matter, ejected by newly born stars at speeds of several hundred kilometers per second), and a growing number of confirmed brown dwarfs (dark substellar objects that are too low in mass to sustain hydrogen fusion). The Taurus Molecular Cloud also contains the cold pre-stellar cloud Lynds 1544 (L1544), where Herschel detected more than 2,000 Earth oceans-worth of water vapour, liberated from icy dust grains by high-energy cosmic rays passing through it.
To produce that amount of vapour, there must be more than three million frozen Earth oceans’ worth in Lynds 1544. The Herschel observations also revealed that the water molecules are flowing towards the heart of Lynds 1544 where a new star will probably form, indicating that gravitational collapse has just started. Some of the water vapour detected in Lynds 1544 will go into forming the star, but the rest will be incorporated into the surrounding disk, providing a rich water reservoir to feed potential new planets. There are no large stars to illuminate the Taurus Molecular Cloud, so it’s completely black in visible light. Studying the Taurus Molecular Cloud and other stellar nurseries will learn us more of the physical and chemical conditions that lead to the formation of molecular clouds, and the very early phases of star- and planet formation.
Astronomers have detected "natural gas" on the surface of Pluto, in the form of frozen ice. Using the recently commissioned Japanese Subaru telescope on Hawaii, scientists report the detection of ethane ice on Pluto, the most distant planet in our solar system.
The telescope allows the chemistry of Pluto's surface to be revealedIt is a significant discovery because it may be left over from the original cloud of gas, ice and dust that formed our Sun and planets. The light reflected from Pluto and Charon has some wavelengths depleted because they have been absorbed by nitrogen, methane and carbon monoxide, all existing in the form of ice on the surface of Pluto. Surprisingly a detailed analysis of the light from Pluto and Charon reveals that they are not alike. Pluto is covered in frozen nitrogen, methane, carbon monoxide and ethane "ice" (all at a temperature colder than -346 Fahrenheit or -210 degrees Centigrade). Charon appears to be mostly covered in the more familiar water ice at a similarly low temperature. Astronomers are a little puzzled abut the differences but some suggest that it lends support to the theory that the Pluto-Charon system formed out of the shattered remains of a single body following a planetary collision back when the solar system was young. Pluto was discovered in 1930 and is the furthest known planet in our solar system, taking 249 years orbit the Sun. Life as we know it on Earth is linked to our star, the Sun, which provides our planet with just the right amount of heat and energy for liquid water to be stable in our lakes, rivers and oceans. The Sun formed some 4.5 billion years ago when gravitational attraction caused a massive cloud of gas and dust to collapse. As the Sun ages it will enter another stage of stellar evolution where it’s atmosphere begins to inflate.
As time goes on, the Sun will start shedding its atmosphere and will continue to grow into a massive planetary nebula, which is like a large cloud of gas ejected from the old star.
Life as we know it is intrinsically tied to the life-cycle of the Sun because we rely on its light for energy. In 1816, Lord Byron wrote the poem Darkness, which is often cited as an early example of a sub-genre of science fiction that tells the tale of a dying Earth. Rather than leading us to a rocky ball of ice, an ageing Sun will instead blast the Earth with ever-increasing heat. Previous models have predicted that an increase of just 6 percent in the solar constant (a measure of incoming solar electromagnetic radiation) would cause a runaway greenhouse effect on Earth that would render the planet uninhabitable as the oceans boil away to space. New research shows that the accuracy of previous studies, which were based on ‘one-dimensional’ models of Earth’s climate, could be improved.
Wolf and his colleague Brian Toon, also of UC Boulder, used complex, three-dimensional climate models in order to bring more detail into the picture. The added detail of the 3-D models showed that the Earth could remain habitable for longer than previously expected. It’s important to note that a habitable Earth in terms of astrobiology is not necessarily habitable for human beings. Theories about the future of habitability on Earth are not simply based on models of the Sun.
In a study published last year in the scientific journal Astrobiology, a team of researchers from the United Kingdom approached the question of habitability from a different angle.
Their simulations identified a point at which increasing radiation from the Sun would render the Earth unable to support liquid water. In their ‘climate’ approach, Wolf and his colleagues also used a constant value for carbon dioxide (CO2) and methane (CH4) in their simulations, effectively taking these two elements out of the equation. Comparative planetology works both ways, and studying the future of Earth can also help astronomers find exoplanets that might fit the habitability bill themselves. This artist’s concept illustrates a young, red dwarf star surrounded by three planets. Coming from the angle of Earth’s climate, the study by Wolf and colleagues also has wider implications.


The Earth orbits around the Sun in a region known as the ‘habitable zone,’ where the energy from the Sun is just right for liquid water to remain stable at the planet’s surface. When a planet sits too close to a star, the energy can cause a runaway greenhouse similar to what we see today on Venus. As a star ages and expands, the habitable zone also moves further outward in a solar system. The two studies combined highlight the increasing crossover between earth sciences and the search for extrasolar planets. The studies provide new insight into the distant future of Earth and that of planets millions of light years away.
Observations with the Herschel Space Observatory show that supernova 1987A produced enough dust to make 200,000 new planets.
THE HERSCHEL SPACE OBSERVATORY has discovered that titanic stellar explosions can be excellent dust factories.
The discovery was made while Herschel was charting emission from cold dust in the Large Magellanic Cloud, a small galaxy near to the Milky Way. Herschel saw a spot of light at the location of supernova 1987A, an exploding star first seen from Earth in February 1987, and the closest known supernova in the past 400 years. Astronomers have been studying the remains of the explosion as its blast wave expands into its surroundings. Although they are only a minor part of the Universe and our Solar System, they are the main constituents of rocky planets like Earth and thus of life itself—many of the atoms we are made of were once part of the dust in the Universe.
However, it is not fully understood where this dust comes from, and especially where it came from in the young Universe.
The many old red giant stars in today’s Universe are thought to be the major dust producers, with the grains condensing like soot in a chimney as warm gases flow away from the star. However, there were no such stars in the early Universe—yet we know there was already dust. Since there were plenty of supernovae in the young Universe, this could help to explain the origin of dust seen at those times. Herschel has discovered enough water vapour to fill Earth’s oceans more than 2000 times over, within a gas and dust cloud that is on the verge of collapsing into a new Sun-like star. Stars form within cold, dark clouds of gas and dust – ‘pre-stellar cores’ – that contain all the ingredients to make solar systems like our own. The new Herschel observations of a cold pre-stellar core in the constellation of Taurus known as Lynds 1544 are the first detection of water vapour in a molecular cloud on the verge of star formation. The observations also revealed that the water molecules are flowing towards the heart of the cloud where a new star will probably form, indicating that gravitational collapse has just started.
Some of the water vapour detected in L1544 will go into forming the star, but the rest will be incorporated into the surrounding disc, providing a rich water reservoir to feed potential new planets. Well, first off, a molecular cloud is basically a cloud up in the space, and is composed mainly of molecular hydrogen and helium. Our own Milky Way, contains about 2,000 Giant Molecular Clouds, plus other numerous smaller clouds. The vast cloud is one of the nearest large stellar nurseries to Earth and contains over 400 young stars.
The vast majority of gas in these clouds consists of molecular hydrogen (H2), and it is in these cold regions that stars are born.
Before these observations, the understanding was that all the water was frozen onto dust grains because it was too cold to be in the gas phase and so it could not be measured. There is enough material to form a star at least as massive as our Sun, which means it could also be forming a planetary system, possibly one like ours.
And for the first time a narrow absorption feature has been seen in Pluto's spectrum that is the fingerprint of solid ethane. This is when the Sun will expand into a red giant star, swallowing planets in the inner Solar System – possibly including the Earth.
This is a sort of recycling stage, where elements created by the star are sent back to the interstellar medium, thereby providing new materials for more stars to form. Many people think the different stages in the life of a star are actually different types of stars, rather than just stages in the life of a single star.
For decades, scientists have studied various scenarios for how an ageing Sun will affect Earth’s future habitability. In his vision of Earth’s future, the Sun has died and left our planet barren and ice covered, floating in a sea of black and empty space. Before the Sun expands to a red giant, this increased heat will cause dramatic climatic change on our planet. This image compares the size of the Sun today (yellow dot on the left) to the size of the Sun as a Red Giant. Based on this number, Earth’s habitability could come to an end in around 650 million years from now. Each wavelength represents material at a different temperatures, helping scientists understand how it is moved and heated through these events. In Wolf’s scenario, 1.5 billion years from now, the mean surface temperature of the Earth is estimated to be over 100? F.
With astronomical observations, scientists have been able to observe stars in various stages of their life cycles.
Rather than looking at how a planet evolves over time, they estimated the output of energy from a star as it ages.


There are so many factors involved in shaping Earth’s climate and how it responds to changes in the Solar System environment that it is necessary to look at a few pieces of the puzzle at a time in order to build a larger picture. Rushby and colleagues studied our solar system with a model that was developed to study habitability around other stars. Such stars are dimmer and smaller than yellow stars like our sun, which makes them ideal targets for astronomers wishing to take images of planets outside our solar system, called exoplanets. Life as we know it requires water to survive, so identifying the ‘habitable zone’ around distant stars is the first step in the hunt for Earth-like worlds. Eventually, this zone is pushed out beyond the orbits of inner planets that were once happily orbiting inside of it. Tools developed to study our home planet can now be adapted to study planets in other systems, and vice versa.
In space, the dust mixes with gas to become the raw material for new stars, planets and, ultimately, life. It is the perfect observatory for the job because cold dust radiates far-infrared light, the wavelengths Herschel is designed to detect.
They reveal cold dust grains at about -250 degrees C, which nevertheless emit more than 200 times the Sun’s energy. Surprisingly, there turned out to be about a thousand times more dust than astronomers had thought a supernova was capable of producing—enough to make 200,000 planets the size of Earth.
The dust’s heavy atoms like carbon, silicon, oxygen and iron were not produced in the Big Bang and must have formed later. The astronomers speculate that the dust condenses from the gaseous debris as it expands from the explosion and cools. Click the RSS Feed link at the top right-hand corner of this page, and then save the RSS Feed page to your bookmarks. Water, essential to life on Earth, has previously been detected outside of our Solar System as gas and ice coated onto tiny dust grains near sites of active star formation, and in proto-planetary discs capable of forming alien planetary systems. More than 2000 Earth oceans-worth of water vapour were detected, liberated from icy dust grains by high-energy cosmic rays passing through the cloud. And a Giant Molecular Cloud is a molecular cloud that is a hundred times the mass of our sun. They also look like dark clouds of dust and gas, because they do not give off their own light and thus quite hard to detect.
Since cold H2 does not easily radiate, astronomers trace these cosmic cribs by targeting other molecules, which are present there in very low abundance but radiate quite efficiently. On Pluto it is an indicator of how the planet and its large companion Charon, may have formed.
Venus experiences a runaway greenhouse and the average surface temperatures are thought to be around 864?F. Eventually, the sunlight that supports life will become too great, and it will bring an end to habitability on our planet. The bright ball of light in our sky goes about its days generating energy by fusing hydrogen atoms in its core. Next, the old core of the Sun will cool and collapse into a dense but small hunk of mass known as a white dwarf star. However, a more recent study has extended the expected lifetime of Earth as a habitable world. When discoveries of exoplanets entered the scene, astrobiologists began to hunt for a view of our own future by looking at rocky worlds around such stars.
With further studies, the goal will be to include more factors like carbon dioxide and methane to the mix to gradually increase the accuracy of the models. By using models developed for Earth, Wolf and Toon have shown that this process of a shifting habitable zone around a star is actually delayed. The models used to study circulation of the Earth’s climate are also some of the most prominent ones employed in the study of current climate change on our planet. The work utilized the Janus supercomputer (supported by the National Science Foundation), and further research on this topic is also supported by the NASA Planetary Atmospheres program. Giant Molecular Clouds are very cold, with temperatures from about 253 to -233 degrees Celsius (-450 to -380 degrees Fahrenheit or 10 to 50 degrees Kelvin).
The most important of these tracers is carbon monoxide (CO), which emits light more readily and therefore is more easily detectable. These distant systems can provide points of comparison between the models and real-life observations. Watson of the University of Exeter) found a longer lifespan for Earth’s habitability, which they estimated to be around 1.75 billion years. While Wolf and Toon’s work shows that Earth can maintain habitability long after the Sun has caused the planet to heat up, it’s important to remember that this potential for life is based on liquid water and does not include humankind.
Long before the Sun becomes a red giant some 4 or 5 billion years from now, our planet will be rendered uninhabitable. However, in real life, humankind will be gone long before a red giant star fills our skies. They arrived at this number from the vantage point of energy output from the Sun, not by modelling how the climate of the Earth itself is affected.



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