WHAT IS A BLACK HOLE...?

Hi guys do you know what is a black  hole....?

Black holes are the most mysterious bodies in the whole universe. Astronomers consider a black hole as a stage in the evolution of the star. They are probably formed when a supernova occurs. If a star is ten times more massive than the sun, no known force can stop the increasing gravity, and it will collapse to a point of infinite density. Before  this stage is reached, within a certain radius, light itself becomes trapped, and the object becomes invisible, and becomes a black hole. With the invention of invisible radiations like radio waves,ultraviolet, X-rays etc. locating the  invisible black hole has been possible. Black holes are the densest areas in the Universe.

WHY DON'T ARCTIC FISH FREEZE...?

We may think that why don't the Arctic fish fish freeze...?

Fish are cold blooded animals whose body temperature changes according to the surroundings. So, normally at the below freezing temperature of Arctic, fish should be freezing or they shouldn't be living there at all! The puzzle has been solved by scientists who have discovered that the fish do possess some antifreeze substance in their blood. The Arctic sculpin, manufactures an antifreeze protein in its blood. This depresses the freezing temperature of its plasma sufficiently. 

ARE THERE MOUNTAINS AND VOLCANOES UNDER THE SEA..? DO ALL SEAS HAVE TIDES...?

You may have a doubt that are there any mountains and volcanoes under the seas..?


There are thousands of mountains under the sea. All of them are volcanoes, but some of them do not erupt anymore. There is long chain of undersea mountains all the way down the Atlantic Ocean. It is called the Mid-Atlantic Ridge, and is the longest chain of mountains in the world. The highest sea mountains are over 10,000 metres tall.



You may also doubt that do all seas  have tides..?

Tides are caused due to the pull of the  moon, and to a smaller extent, the Sun. In  general, the larger body of water, the more noticeable the tide. The height of the tide depends on the size, shape, and depth of the sea in a given location. In enclosed seas like the Mediterranean, there is hardly any tide at all, because it is surrounded by land on all sides. The rise and fall of the water may be only a few centimetres.

WHO WERE THE FIRST ARTISTS...?

Have you guys ever think about the first artist....?

About 30,000 years ago, Man first began to paint on the walls and roofs of caves and on rocks. The most common themes in cave paintings are large wild animals, such as bison, horses and deer. Stone Age carvings have also been found as far north as Scandinavia. The main form o prehistoric art is 'rock art'. This includes petroglyphs, otherwise known as rock carvings. An example is the Blombos cave engravings. A second form are pictographs, which includes drawn or painted signs, geometric symbols, hand stencils, and hand prints, see for instance the tragic Gargas Cave Hand Stencils. Rock art can be seen in Europe, Asia, Africa, Australasia, Oceania and the Americas.

HOW DO EAGLES GLIDE, WITHOUT FLAPPING THEIR WINGS..?

When people see the Eagle flying , they may think that how do they do it without flapping their wings....?

If you watch an eagle's movement through binoculars, you will see that even though the bird appears to be gliding lazily, it is actually very active. Its outer wing feathers and tail  feathers are in constant motion, catching up-drafts of warm air, and steering the bird through the air currents. Like other objects, which are heavier that air, birds in flight are constantly falling. When a bird is in an up-draft of warm air, it is carried up more quickly than it falls.  At this time, it can fly higher. The bird now tries to keep itself in this column of air by steering with its wing and tail feathers. When the birds moves into a column of downward moving cooler air, it falls rapidly.  However , it now uses its wings to help it glide, as quickly as possible, into another column of upward moving warm air. The speed that the bird attained while gliding downward in the 'cool column' enables it to sweep upward more quickly when it enters the 'warm column'.

CAN WE SOME DAY, LIVE ON VENUS...? VENUS - TOPOGRAPHICAL MAP

Venus was at one  time considered to be more likely home than Mars for Earthlings, but revelations by way of space probes, radar and radio astronomy are not encouraging in this respect. The average surface temperature is indicated at a rather very uncomfortable 420 degree celsius ! Then, too, there is no water on the surface; the atmosphere is deadly; and the pressure is tremendous.

TOPOGRAPHICAL MAP 

ARE COMETS COVERED IN AN ENVELOPE...?

People doubt that are the comets are covered in an envelope..?  Here is the answer for them.....


As a comet absorbs ultraviolet light, chemical processes release  hydrogen, which escapes the comet's gravity and forms a hydrogen envelope. This envelope cannot be seen from Earth, because its light is absorbed by our atmosphere, but it has been detected by spacecrafts.

COULD WATER EXIST ON MERCURY..?

In 1991, scientists bounced  radio waves off  Mercury, and found an  unusual bright return from the north pole. The apparent brightening at the north pole could be explained  by ice on, or just under the surface.

            But, is it possible for Mercury  to have ice..? Yes. Because Mercury's rotation is almost perpendicular to its orbital plain, the north pole always sees the Sun just above the horizon.

            The insides of craters would never be exposed to the sun, and would remain very cold. This freezing temperature could trap water outgassed from the planet, or ice brought to the planet from impacts with comets.

    These ice might be covered with a layer of dust, and would show bright radar returns.

WHY DO SOME PLANETS HAVE RINGS..? WHAT ARE THEY MADE OF...?

SATURN

The people have the doubt about the rings of some planets and what are they made of..?

The rings of  Jupiter, Uranus and Neptune are made of dust, very tiny pieces of rock and ice. The rings of Saturn are made of large pieces of ice.

We don't know for sure where these rings came from. In some cases, the rings have come from dust knocked off of the planets, moons by meteorite bombardment, but some of them might have come from moons torn apart by the planet's gravity, or they could have formed as the planets formed.

Saturn's rings are the most magnificent; they are bright, wide and colourful. Uranus has thirteen dark rings around it, and Neptune's rings are also dark, but contain a few bright arcs.

HOW DID THE UNIVERSE BEGIN...?

Most of the people have the doubt how did the universe begin...?  There are many popular theories regarding the origin of the universe. The most prominent among them is  ' the Big Bang ' theory. This theory was first  suggested by a Belgian priest  named, Georges Lemaitre in the 1920s. Later, the idea got wide acceptance through the studies of Edwin  Hubble, Arno Penzias, and Robert Wilson.

The Big Bang theory was born out of the observation that galaxies are moving away from one another at great speed, as if they had been geared by an ancient explosive force. The theory states that some 20 billion years ago, a massive blast -a Big Bang - occurred, and that allowed all the matter in the Universe to spring from some unknown type of energy. After the Big Bang, the universe expanded at a great speed. This expansion still continues, but much more slowly.

But there are many scientists who still doubt the authenticity of Big Bang theory, because it leaves several questions  unanswered......

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