Jun 18

Astronomy - What it can be

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Astronomy can be defined as the branch of science that deals with the study of natures and motion of celestial bodies like stars, planets and galaxies.

There are yet different definitions for Astronomy. This includes the study of matter and objects outside earth’s atmosphere and having their own physical and chemical properties.

Some different views include –Astronomy is the study of everything. This is because astronomy is the study of universe and everything is part of the universe.

One can say that all these definitions are correct and hence there are many sub fields within astronomy. Cosmologists, Astrometrists, Planetologist, Radio astronomers, Mathematical astronomers are some among these sub divisions. Cosmologists study universe as a whole including its origin and beginning. Planetologists do study about all those planets with in the solar system and those orbiting distant stars. Astrometrists calculate distances connected with universe. Again Radio astronomers use radio telescopes to study the universe. Numbers, calculations and statistics are used by mathematical astronomers in order to explain universe.

We can’t say that astronomy is a stand alone subject. It is a combination of different fields. These fields include mathematics, geology, chemistry, physics, geology, biology. Physics can be said to be as one of the most integral part of astronomy. That is why some of the astronomers are known as Astrophysicists. Astronomy can be said to be the oldest science. During the early age, astronomers were priests and holy men, who tried to fix the puzzle of the universe. They tried to determine planting cycles and celebrations. Astronomy theories where first developed and introduced by ancient Greeks. They made out theories about the universe design as a whole. There were many astronomers who proved them to be great astronomers. Later many of the facts provided by them proved to be wrong, as technology came forward with a helping hand. Some of them include Ptolemy, Copernicus, Galileo Galilee, Johannes Kepler etc. but one fact is sure that with out the contributions of all those greats the facts known today could not have reached upon.

Again it can be said that astrology is the study of cosmos. An attempt to understand the history and make up of universe can be termed to be as astronomy. An unlimited area of fields is covered under astronomy. They include stars, nebula, planets, sol, star clusters, galaxies, dark matter, black holes etc. each of these can be again divided into multiple topics. Research is done in the whole electromagnetic spectrum. This includes ultraviolet, visible, x-ray and infrared. Thus it really covers lots of things when it comes to astronomy.

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Jun 04

Mars and Phoenix - Is the Outlook For Life a Cold Case ?

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The Phoenix Mars Polar Lander is slated to land on Mars’ north pole on May 25th - very soon now! Phoenix is intended to look for signs of microbial life, and there’s a case that evidence may be found on Mars.

The first piece of evidence is purported microfossils found in an Antarctic meteorite in 1997 - this Shergottic meteorite ALH84001, estimated to be 4.5 billion years old, is still the subject of some controversy. There are some who say that the microstructures are evidence of biotic contamination from its long tenure on Earth, others maintain hope that it’s evidence of a link to life on the Mars.

Martian life has a long held a fascination for astronomers - for one, it’s a bright object in the sky, and for two, after the development of the telescope in the 1600s, it showed the most obvious color changes of any object in the sky. From Schiapiarelli to Lowell to Wells, the prospect of Martian life has held the imagination, even as the scientific evidence mounted that such life would be nothing at all like we’d expect.

The case for life on Mars is reinforced by the exposure of bacteria on Lunar missions - samples went out, and came back, and were able to survive the harsh Solar and Van Allen radiation belts - even some of the plasma and thermal changes of reentry through the Earth’s atmosphere. So life is remarkably hardy and capable of surviving in the vicious environment of space. Achaeobacteria and tube worms living on volcanic vents show that life can survive and thrive wherever there’s a source of energy to exploit, even down in the depths of the ocean where sunlight isn’t even a memory.

However, the question of life on Mars has a few more complications. For one, it’s a cold case -whether there was life in the past, Mars’ surface conditions have changed over the last 5 billion years. There are definite epochs in Martian geology (called areology), where Mars speculation shows Mars having a thicker atmosphere than now, and receding (and advancing) surface water levels. Mars’ current climate cannot support liquid water on the surface - the temperature is too low, and the atmospheric pressure is too low; if you took a tray of ice cubes out on the surface, they’d slowly evaporate by sublimation, the way dry ice does on Earth.

What caused these changes in Martian climate? Plate tectonics, or rather, the lack of them. Earth’s biosphere is driven in large part by plate tectonics, which serve to bury carbon (in the form of limestone) caused by sedimentation. The driving force on plate tectonics is the decay of radioactive elements in the Earth’s core.

Venus also shows evidence of having had plate tectonics in the past; its plate tectonics appear to have stopped due to the lack of water in the subsurface crust - the water in the oceans is far from being the majority of it on the planet; most of the rest is seepage down into the Earth’s mantle, where it acts as a lubricant.

On Mars, due to short range radio surveys by the Mars Reconnaissance Orbiter, we now show that Mars’ crust isn’t as flexible as Earth’s - it’s not being pressed down as much as it should be by the mass of the Martian polar ice cap. This is indicative that Mars is tectonically dormant.

Why does tectonic dormancy matter for the case for life on Mars? Tectonic activity is the likely driving energy source for any Martian microbes out there, and it’s the only candidate presently known to make long standing seeps of liquid water, which is necessary for life as we know it.

Phoenix will be landing at the Martian north pole to give us some answers - but even if it finds nothing, there’s no reason to give up hope. Mars has a surface area equal to all of Earth’s dry land put together. Phoenix will only be able to sample an area comparable to a ring of soil around an office cubical.

Phoenix’ other mission profile is to give climate data on Martian weather patterns and observational data on the polar winter, and it’s slated to provide data for at least six months, with optional extensions for years. (The Spirit and Opportunity rovers are now approaching the fourth anniversary of the beginning of their 90 day survey…)

Phoenix live commentary from NASA begins at at 3:30 pm USA Pacific time on the 25th as the craft prepares for its decent into the martian atmosphere, or about 9:30 on the morning of the 26th for Eastern Australia.

Ian Maclean - Author, Presenter and Science Show hostHomepages: http://www.nightskysecrets.com and http://www.askthescienceguru.com
Discover the hidden secrets of the night sky for yourself.

On nightskysecrets.com you will be able to download a f r e e copy of my Audio “Night Sky Secrets - Revealed” plus pick up a f r e e subscription to nightskysecrets, where you will be kept up to date with all the latest events you can see in the night sky and gain subscriber access to my blog page, often with maps, charts, photos and movies to compliment these articles and much more.At askthescienceguru you can download and subscribe to the RSS feed of the latest podcasts from my weekly radio show “The Science Hour”

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May 29

The Planets

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To the ancient astronomers, Saturn appeared to be the most distant planet, at the edge of the universe. That belief continued until the year 1781. In the year William Herschel (1738-1822), a German-born musician living in England, discovered a planet beyond the orbit of Saturn.

At the time, Herschel was an amateur astronomer. Using homemade telescope set up on the sidewalk in front of his home, he observed a speck of light that moved from night to night. Herschel at first thought if was a comet. But other astronomers worked out the orbit of the moving light, and Herschel’s discovery was recognized as a planet. It was named Uranus.

Neptune was discovered with the aid of mathematics. In the years following the discovery of Uranus, astronomers were puzzled by its failure to move as expected. Up to 1822, the planet seemed to move too quickly; then it lagged. By the 1840’s, it was suspected that the peculiar motion was caused by the gravitational pull of and even more distant planet. Two astronomers, working independently, calculated where the suspected planet must be. They were John Couch Adams, of England, and Urbain Leverrier, of France. In 1846, Johann Galle, a German astronomer, found the planet just where Adams and Leverrier had predicted it would be. The planet was named Neptune.

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May 11

Galaxies In The Outer Space World

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Galaxies are multifaceted in that they often encompass many different kinds of outer space matter, such as star systems, dust particles, and gases.

Each individual galaxy is filled with millions and trillions of bright, beautiful stars, and on each galaxy, these stars have their own distinct path, or orbit, to follow. When speaking of how large or small galaxies are, they are measured in light years, rather than acres or miles, and the average galaxy is often millions of light years across, most even larger.

Many scientists and astronomers have debated the existence of what is known as dark matter for years, and still have been able to reach a definitive conclusion as to whether it does actually exist or not. They do agree in believing that most space galaxies are gilled with massive black holes and other unknown rarities yet to be discovered. There are literally billions of different galaxies all floating around in space, and probably billions more that we do not know about, or do not have the technology to see yet. When you think about that, about how big galaxies are, and about how many there actually are in existence, can you imagine how big the whole of outer space must be? It blows your mind just to think about it.

When you talk to someone about galaxies, most of us often name the Milky Way, as it is the galaxy that we are the most familiar with. On clear nights, you can actually see the Milky Way galaxy when looking up at the night sky. We know that the Milky Way galaxy is extremely massive in size, and is made up of trillions and trillions of stars. One shocking fact about the Milky Way, to me anyway, is that when compared to the sun, it is literally huge. We consider the sun to be enormous, but if you were to place the sun and the Milky Way side by side for comparison, you would have to use a microscope to see the sun, if that helps you get a better mental image of just how massive the Milky Way is.

To help them keep better track of all of the galaxies existing in the universe, astronomers and scientists have classified them into three different groups. One of these three groups has been dubbed the spiral, given its name due to all of the galaxies in it being in a spiral shape. The stars surrounding the galaxies in the spiral group do not move around them in a certain path, as in many other galaxies, they instead gravitate in and out through the spirals.

Galaxies belonging to the field group are those galaxies that seem to float freely through space, alone in a huge world, not really touching or near other galaxies. There are not very many galaxies in this group, and perhaps it is the smallest of all three groups.

The last group is perhaps the largest of all three, the cluster group. Galaxies within the cluster group are all squeezed into the same teeny space, but travelling together, are massive in size. There are also galaxies that are referred to as super clusters, where there are many galaxies all in one, again packed tightly into the same space.

For more vital information about galaxies and related welcome to visit http://www.newsinastronomy.com

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