~astro-craze~

After posting all 14 posts about my astronomical craze, in my finals post here, I would love to tell you guys about Telescope. Without the invention of telescope, I don’t think understanding The Universe is possible. Thanks to Hans Lippershey and Zacharias Janssen!

The idea that a mirror could be used as an objective instead of a lens was being investigated soon after the invention of the refracting telescope. The potential advantages of using parabolic mirrors, primarily reduction of spherical aberration with no chromatic aberration, led to many proposed designs and several attempts to build reflecting telescopes. In 1668,Isaac Newton built the first practical reflecting telescope, which bears his name, the Newtonian reflector.

One of the world greatest inventions of Telescope is (in my opinion) The Hubble Telescope is a space telescope that was carried into orbit by a space shuttle in April 1990. It is named after the American astronomer Edwin Hubble. Although not the first space telescope, Hubble is one of the largest and most versatile, and is well-known as both a vital research tool and a public relations boon for astronomy. The HST is a collaboration between NASA and the European Space Agency, and is one of NASA's Great Observatories, along with the Compton Gamma Ray Observatory, the Chandra X-ray Observatory, and the Spitzer Space Telescope.

Hubble is the only telescope ever designed to be serviced in space by astronauts. Four servicing missions were performed from 1993–2002, but the fifth was cancelled on safety grounds following the Space Shuttle Columbia disaster. Remember the heart- wrecking news few years back, on February 1, 2003?

Anyhow, the engineering aspects of The Hubble Telescope are extremely complicated and only geniuses can understand them. It is very delicate. This design, with two hyperbolic mirrors, is known for good imaging performance over a wide field of view, with the disadvantage that the mirrors have shapes that are hard to fabricate and test. Construction of the mirror components of telescope began at 1979, and ended in May 1981! Can u imagine how much of efforts, hard work, blood, sweat and tears were put through when building it?

Let us all appreciate Him for the wonderful nature, Universe that is blessed to us. Without all His creation, human beings will never discover knowledge. Without His blessing, Human will not evolve into what we are today; most probably we will still be in ancient ages. To show appreciation to Him, we should start love ourselves, care for those around us. The least we can do is, appreciate His creation: NATURE.

For more info, log on to:

1) www.hubblesite.org

2) hubble.nasa.gov/

I love chocolate. Everyone loves chocolate. The other day when I was munching on a bar of chocolate, it tasted superb and I was flipping the wrapper to see its ingredient. Then the next thing I saw caught my eyes. Its manufactured by Milky Way Corp.

We are actually in the galaxy named, The Milky Way. It is a barred spiral galaxy that is part of the Local Group of galaxies. It is one of billions of galaxies in the observable universe. Remember I posted something about my previous post, Andromeda? Milky Way is second largest after the Andromeda.

In Latin, the term VIA LACTEA means the pale band of light formed by stars in the galactic plane as seen from Earth. That’s how Milky Way got its name from.

As a galaxy, the Milky Way is actually a giant, as its mass is probably between 750 billion and one trillion solar masses, and its diameter is about 100,000 light years. Radio astronomical investigations of the distribution of hydrogen clouds have revealed that the Milky Way is a spiral galaxy. Therefore, our galaxy has both a pronounced disk component exhibiting a spiral structure, and a prominent nuclear region which is part of a notable bulge or halo component. Decade-long observations have brought up more and more evidence that the Milky Way may also have a bar structure. (hmmm.. Milky way chocolate bar..)

The spiral arms of our Milky Way contain interstellar matter, diffuse nebulae, and young stars and open star clusters emerging from this matter. On the other hand, the bulge component consists of old stars and contains the globular star clusters; our galaxy has probably about 200 globulars, of which we know about 150. 50 of them are yet to be discovered! These globular clusters are strongly concentrated toward the Galactic Centre. From their apparent distribution in the sky, indicates that this centre of the Milky Way lies at a considerable distance in the direction of Sagittarius and not rather close to us, as had been thought previously. ( I’m a Sagittarian =-)).

for more info, log on to

a) en.wikipedia.org/wiki/Milky_Way

b) seds.org/messier/more/mw.html

c)www.space.com/milkyway/

I was watching the television series the other day. The title was ANDROMEDA. The name itself fascinated me, and so I decide to Google it. I never believed what I found.. Andromeda is a galaxy, just like our Milky Way, where The Sun System located. I’m wondering whether Andromeda sustains any live in there.

Andromeda, also known as Messier 31, is the nearest spiral galaxy to our own, the Milky Way. It is visible as a faint smudge on a moonless night, it is one of the farthest objects visible to the naked eye, and can be seen even from urban areas with binoculars. It gets its name from the area of the sky in which it appears.

Andromeda was named after the mythological princess Andromeda. Andromeda is the largest galaxy of the Local Group, which consists of the Andromeda Galaxy, the Milky Way Galaxy, the Triangulum Galaxy, and about 30 other smaller galaxies.

The Andromeda Galaxy is approaching the Sun at about 100 to 140 kilometres per second, so it is one of the few blue shifted galaxies. The Andromeda Galaxy and the Milky Way are thus expected to collide in perhaps 4.5 billion years, although the details are uncertain since Andromeda's tangential velocity with respect to the Milky Way is only known to within about a factor of two.

I really hope scientists will work something out as we don't collide. On the next post, i will introduce The Milky Way to you..

=-)

for more info, surf on to

a)en.wikipedia.org/wiki/Andromeda_Galaxy

As what I have shared with you in previous post, white dwarf arises from when small stars, (those which reach up to eight times as massive as our SUN!!), reach the end of their long evolutions.

These ancient stars are known incredibly dense. A teaspoonful of their matter would weigh as much as AN ELEPHANT! Amazing isn’t it? I wonder how The Universe can hold these enormous elements together..

Stars, like our sun, it fuse hydrogen in their cores into helium.White dwarfs are stars that have burned up all of the hydrogen they once used as nuclear fuel. This is what I meant by end of it’s evolution.

Eventually, over tens or even hundreds of billions of years, a white dwarf cools until it becomes a black dwarf, which emits no energy. Because the universe's oldest stars are only 10 billion to 20 billion years old there are no known black dwarfs yet! I hope it will be discovered soon as I am really interested to know how it looks like.

But not all white dwarfs will spend many millennia cooling their heels. Those in a binary star system may have a strong enough gravitational pull to gather in material from a neighboring star.

Other than white dwarf, in the Universe, there is such thing known as Red Dwarf as well. Unlike white dwarf, Red dwarfs are very low mass stars with no more than 40% of the mass of the Sun.

Consequently they have relatively low temperatures in their cores and energy is generated at a slow rate through nuclear fusion of hydrogeninto helium. And they transport their energy from core to the surface by convection, which is totally different from the white dwarves.Convection occurs because of the interior part of Red Dwarf, has higher density compared to the temperature. As a result, energy transfer viaradiation is decreased, and instead convection is the main form of energy transport to the surface of the star.

As red dwarfs are fully convective, helium does not accumulate at the core and, compared to larger stars such as the Sun, they can burn a larger proportion of their hydrogen before leaving the main sequence. As a result, red dwarfs have estimated lifespans longer than the estimated age of the universe, and stars with less than 0.8 solar masses have not had time to leave the main sequence. The lower the mass of a red dwarf, the longer the lifespan.

It is believed that the lifespan of these stars exceeds the expected 10 billion year lifespan of the sun by the third or fourth power of the ratio of their masses to the solar mass; thus a red dwarf with 0.1 solar mass may continue burning for 10 trillion years. As the proportion of hydrogen in a red dwarf is consumed, the rate of fusion declines and the core starts to contract. The gravitational energy generated by this size reduction is converted into heat, which is carried throughout the star by convection.

One mystery which has not been solved as of 2009 is the absence of red dwarf stars with no metals. Metals here as in like Hydrogen or Helium. Unlike all the other Stars, which they have at least one type of metal, Red Dwarf has none.

In The Big Bang theory, which was my first post in this blog, it predicts the first generation of stars should have only hydrogen, helium, and trace amounts of lithium. Hmmmmm.. Another mystery.. This is why I love the knowledge about the Stars and stuff, fun!

for more info, log on to

-science.nationalgeographic.com/.../white-dwarfs-article.html

news.nationalgeographic.com/.../100525-science-space-planets-tilted-orbits-stars/

Some stars behave as if it's better to burn out than to fade away. These stars end their evolutions in massive cosmic explosions known as supernovae.

When supernovae explode they produces matter into space at some 15,000 to 40,000 kilometers per second. These blasts produce much of the material in the universe. These includes some elements, like iron, which make up our planet and even ourselves. Heavy elements are only produced in supernovae, so all of us carry the remnants of these distant explosions within our own bodies.

Supernovae add enriching elements to space clouds of dust and gas, further interstellar diversity, and produce a shock wave that compresses clouds of gas to aid new star formation.

But only a select few stars become supernovae. Many stars cool in later life to end their days as white dwarfs and, later, black dwarfs.

As for massive stars, which some of them maybe many times larger than our own sun, may create a supernova when their core's fusion process runs out of fuel. Star fusion provides a constant outward pressure, which exists in balance with the star's own mass-driven, inward gravitational pull. When fusion slows, outbound pressure drops and the star's core begins to condense under gravity. It becomes ever denser and hotter!

To outward appearances, such stars begin growing, swelling into bodies known as red supergiants, which I posted in earlier posts. But at their cores shrinking continues, making a supernova imminent. Imminent here means overhanging, or in another word, it’s jutting out.

When a star's core contracts to a critical point a series of nuclear reactions is unleashed. This fusion staves off core collapse for a time—but only until the core is composed largely of iron, which can no longer sustain star fusion.

In a microsecond, the core may reach temperatures of billions of degrees Celsius. Iron atoms become crushed so closely together that the repulsive forces of their nuclei create a recoil of the squeezed core—a bounce that causes the star to explode as a supernova and give birth to an enormous, superheated, shock wave.

Supernovae also occur in binary star systems. Smaller stars, up to eight times the mass of our own sun, typically evolve into white dwarves. A star condensed to this size, about that of Earth, is very dense and thus has strong enough gravitational pull to gather material from the system's second star if it is close enough.

A supernova can light the sky up for weeks, and the massive transfer of matter and energy leaves behind a very different star.

Typically only a tiny core of neutrons, a spinning neutron star, is left to evidence a supernova. Neutron stars give off radio waves in a steady stream or, as pulsars, in intermittent bursts.

If a star was so massive, as in like ten times the size of our sun, it leaves behind a large core, a new phenomenon will occur. Because such a burned-out core has no energy source to fuse, and thus produces no outward pressure, it may become engulfed by its own gravity and turn into a cosmic sinkhole for energy and matter—a black hole, which I already post it before.

In my next post, I will tell you more about white dwarf and red dwarves.

for extra info, please log on to

= science.nationalgeographic.com/science/space/.../cosmic-explosion.html

= en.wikipedia.org/wiki/Supernova

A red giant is a luminous giant star of low or intermediate mass.An evolved giant star with a surface temperature of 2,500 to 3,500°C, a spectral type of M or K, and a diameter between 10 and 100 times times that of the Sun.