Hubble Captures a Collection of Ancient Stars The cluster is composed of a large number of stars, tightly bound to each other by gravity. However, this was not known when Charles Messier first observed it in January Astronomers typically infer important properties of globular clusters by looking at the light of their constituent stars.
Chemistry in its element: But for this chemist a helium filled bobbing balloon is actually a source of pain and not a source of pleasure. Peter Wothers We are all familiar with the lighter-than-air gas helium, but whenever I see a balloon floating on a string, I feel a little sad.
Most people guess that we extract helium from the air, but actually we dig it out of the ground. Helium can be found in certain parts of the world, notably in Texas, as a minor component in some sources of natural gas.
The interesting thing is how this gas gets into the ground in the first place.
The NASA/ESA Hubble Space Telescope has produced this beautiful image of the globular cluster Messier 56 (also known as M 56 or NGC ), which is located about 33, light years away from the Earth in the constellation of Lyra (The Lyre). multiple systems’ interconnections and feedbacks. In addition, Earth is part of a broader system—the solar system—which is itself a small part of one of the many galaxies in the universe. Helium can also be produced by liquefying air and separating the component gases. The production costs for this method are high, and the amount of helium contained in air is very low. Although this method is often used to produce other gases, like nitrogen and oxygen, it is rarely used to produce helium.
Unlike virtually every other atom around us, each atom of helium has been individually formed after the formation of the earth. The helium is formed during the natural radioactive decay of elements such as uranium and thorium.
These heavy elements were formed before the earth but they are not stable and very slowly, they decay. One mode of decay for uranium is to emit an alpha-particle.
This alpha-particle is actually just the heart of a helium atom - its nucleus. Once it has grabbed a couple of electrons, a helium atom has been born.
This decay process for uranium is incredibly slow; the time it takes a given quantity of uranium to halve, its so-called half-life, is comparable to the age of the earth.
This means that helium has been continuously generated ever since the earth was formed. Some of the gas might eventually creep through the earth and escape into the atmosphere; fortunately, when conditions are right, some is trapped underground and can be harvested for our use.
The situation is very different in space. The remaining one percent is made up of all the heavier elements. In the high temperatures of the sun, the hydrogen nuclei are fused together to eventually form helium.
This fusion process, whereby heavier atoms are made from lighter ones, liberates vast amounts of energy. Recreating the process on earth may be the answer to our energy problems in the future. Since helium makes up about a quarter of the mass of the sun, it is not surprising that its presence was detected there over years ago.
What is perhaps surprising, is that helium was discovered in space 26 years before it was found on earth. It has been known for hundreds of years that certain elements impart characteristic colours to a flame - a fact crucial to the coloured fireworks that we enjoy.
Copper, for example, gives a green colour, whereas sodium gives a yellow colour. It is actually possible to identify elements by the careful examination of such coloured flames. The light is split up into a spectrum using a prism or diffraction grating in an instrument called a spectroscope.
Rather than seeing a continuous rainbow of colours, a series of sharp coloured lines is formed. This series of lines is characteristic of the particular element and acts as a sort of fingerprint.
In the 19th century, scientists turned their spectroscopes to the sun and began to detect certain metals there, including sodium, magnesium, calcium and iron. In two astronomers, Janssen and Lockyer, independently noticed some very clear lines in the solar spectrum that did not match up to any known metals.
While other astronomers of the time were unsure, Lockyer suggested these unidentified lines belonged to a new metal which he named Helium after the Greek personification of the sun, Helios.
For over 20 years, no sign of the metal helium was detected on earth and Lockyer began to be mocked for his mythical element. However, in the chemist William Ramsay detected helium in the gas given out when a radioactive mineral of uranium was treated with acid.
The helium formed from the radioactive decay had been trapped in the rock but liberated when the rock was dissolved away in the acid. To this day, helium remains the only non-metal whose name ends with the suffix -ium, an ending otherwise exclusively reserved for metals.
Aside from being used to fill balloons, both for our entertainment, and for more serious purposes, such as for weather balloons, helium is used in other applications which depend on its unique properties. Being so light, and yet totally chemically inert, helium can be mixed with oxygen in order to make breathing easier.
This mixture, known as heliox, can help save new-born babies with breathing problems, or help underwater divers safely reach the depths of the oceans. At minus degrees centigrade, liquid helium has the lowest boiling point of any substance.But all bets are off, if the students journey to the center of the Earth, à la Jules Verne's Otto Lidenbrock or if they venture to one of the solar system's large planets, such as Jupiter or Saturn.
Helium can also be produced by liquefying air and separating the component gases. The production costs for this method are high, and the amount of helium contained in air is very low.
Although this method is often used to produce other gases, like nitrogen and oxygen, it is rarely used to produce helium. Discover how the immense variety of matter--stars, mountains, plants, people--is made by a limited number of elements that combine in simple ways.
In the engaging lectures of The Nature of Matter, no scientific background is needed to appreciate everyday miracles like a bouncing rubber ball or water's astonishing power to dissolve. multiple systems’ interconnections and feedbacks.
In addition, Earth is part of a broader system—the solar system—which is itself a small part of one of the many galaxies in the universe. Helium is so light that it can escape the pull of the earth's gravitational field and leave our planet forever.
This is the fate of the helium in our balloons. Whereas it may be possible to reclaim and recycle other elements that we have used and discarded, when we waste helium, it is lost for good.
The generally accepted age for the Earth and the rest of the solar system is about billion years (plus or minus about 1%). This value is derived from several.