Assam Study Hub

A Store For Every Student's Need.

Assam Study HUB

এই website ৰ জৰিয়তে সমাজৰ দুখীয়া শ্ৰেণীৰ শিক্ষাৰ্থী সকলোলৈ কিঞ্চিৎ মান সহায় আগবঢ়োৱাই হৈছে আমাৰ website ৰ মূল উদ্দ্যেশ্য।

Universe

THE SUN

by Leave a Comment

THE SUN :

 

 

 

 

 

 

 

 

 

 

 

 

 

1. WHAT IS THE SUN?
Ans: The Sun is an average star, just like countless others in the universe. It formed from gas left behind after an earlier, much larger star blew up and now, in middle-age, burns yellow and fairly steadily – giving the Earth daylight and remarkably constant temperatures. Besides heat and light, the Sun sends out deadly gamma rays, X-rays and ultraviolet, as well as infrared and radio waves. Fortunately we are shielded from these by Earth’s magnetic field and atmosphere.

 

 

2. WHAT IS A SOLAR ECLIPSE?

Ans: A solar eclipse is when the Moon moves in between the Sun and the Earth, creating a shadow a few hundred kilometres wide on the Earth.

 

 

3. WHAT MAKES THE SUN BURN?

Ans: The Sun gets its heat from nuclear fusion.Huge pressures deep inside the Sun force the nuclei (cores) of hydrogen atoms to fuse together to make helium atoms, releasing huge amounts of nuclear energy.

 

 

4. WHAT IS THE SUN’S CROWN?

Ans: The Sun’s crown is its corona, its glowing white hot atmosphere seen only as a halo when the rest of the Sun’s disc is blotted out by the Moon in a solar eclipse.

 


5. HOW HOT IS THE SUN?
Ans: The surface of the Sun is a phenomenal 5500″C, and would melt absolutely anything. But its core is thousands of times hotter at over 15 million C.

 


6. WHAT IS THE SOLAR WIND?
Ans: The solar wind is the stream of radioactive particles constantly blowing out from the Sun at hundreds of kilometres per second. The Earth is protected from the solar wind by its magnetic field, but at the Poles the solar wind interacts with Earth’s atmosphere to create the aurora borealis or northern lights.

 


7. HOW OLD IS THE SUN?
Ans: The Sun is a middle-aged star. It probably formed about 4.6 billion years ago. It will probably burn for another five billion years and then die in a blaze so bright that the Earth will be scorched right out of existence.

 


8. WHAT ARE SUNSPOTS?
Ans: Sunspots are dark blotches seen on the Sun’s surface. They are thousands of kilometres across, and usually occur in pairs. They are dark because they are slightly less hot than the rest of the surface. As the Sun rotates, they slowly cross its face – in about 37 days at the equator and 26 days at the Poles. The average number of spots seems to reach a maximum every I| years, and many scientists believe these sunspot maximums are linked to periods of stormier weather on Earth.

 


9. WHAT ARE SOLAR FLARES?
Ans: Flares are eruptions from the Sun’s surface that fountain into space with the energy of one million atom bombs for about five minutes. They are similar to solar prominences, the giant flame-like tongues of hot hydrogen that loop 32,000 km into space.

 


10. HOW BIG IS THE SUN?
Ans: The Sun is a small-to-medium-sized star 1,392,000 km in diameter. It weighs just under 2,000 trillion trillion tonnes.

 

 

The Earth

by Leave a Comment

THE EARTH 

 

 

 

 

 

 

 

 

 

 

1.HOW DID THE EARTH BEGIN ?
Ans: Around 4.6 billion years ago, neither the Earth nor any of the other planets existed. There was just this vast, dark, very hot cloud of gas and dust swirling around the newly formed Sun. Gradually,the cloud cooled and the gas began to condense into billions of droplets. Slowly these droplets were pulled together into clumps by their own gravity and they carried on clumping until all the planets, including the Earth, were formed.But it took another half a billion years before the Earth had cooled enough to form a solid crust with an atmosphere around it.

 

 

 2.HOW BIG IS THE EARTH ?
Ans: Satellite measurements show it is 40,075 km around the equator and 12,757 km across. The diameter between the poles is slightly less by 43 km.

 

 

 3.HOW OLD IS THE EARTH?
Ans: The Earth is about 4.6 billion years old. The oldest rock is about 3.8 billion years old. Scientists have also dated meteorites that have fallen from space, and must have formed at the same time as the Earth.

 

 

4.WHAT SHAPE IS THE EARTH?
Ans: The Earth is not quite a perfect sphere. Because it spins faster at the equator than at the Poles,Earth bulges at the equator. Scientists describe Earth’s shape as “geoid”,which simply means Earth-shaped!

 

 

5.WHAT’S SO SPECIAL ABOUT THE EARTH?
Ans: The Earth is the only planet with temperatures at which liquid can exist on the surface and is the only planet with an atmosphere containing oxygen. Water and oxygen are both needed for life.

 

 

6.WHY DOES THE EARTH SPIN?
Ans: Earth spins because there is nothing to stop it spinning. The Sun’s gravity keeps it in orbit.

 

 

7.EXACTLY HOW LONG IS A YEAR?
Ans: Every year the Earth travels once around the Sun. This epic journey covers a distance of 938,886,400 km and takes exactly 365.24 days,which gives us our calendar year of 365 days. To make up the extra 0.24 days, we add an extra day to our calendar at the end of February in every fourth year which is called the leap year and then we have to knock off a leap year every four centuries.

 

 

8. HOW LONG IS A DAY?
Ans: A day is the time Earth takes to turn once. The stars move to the same place in the sky every 23 hours, 56 minutes and 4.09 seconds (the sidereal day). Our day (the solar day)is 24 hours, because Earth is moving around the Sun, and must turn an extra for the Sun to be in the same place in the sky.

 

 

9. WHO WAS COPERNICUS?
Ans: In the 1500 s, most people thought the Earth was fixed in the centre of the universe, with the Sun and the stars revolving around it. Nicolaus Copernicus(1473-1543) was the Polish astronomer who first suggested the Earth was moving around the Sun.

 

 

 

 

 

♦ Content of the Universe click here

THE MOON

by Leave a Comment

THE MOON 











 

 

 

1. WHAT ARE THE MOON SEAS?

Ans: The large, dark patches visible on the Moon’s surface are called seas, but in fact they are not seas at all. They are huge plains formed by lava flowing from inside the Moon.

2.WHO WERE THE FIRST MEN ON THE MOON?

Ans: The first men on the Moon were Neil Armstrong and Buzz Aldrin of the US Apollo II mission. They landed on the Moon on July 20,1969.As Armstrong set foot on the Moon, he said: “That’s one small step for (a) man, one
giant leap for mankind.”

3. WHAT IS MOONLIGHT?

Ans: The Moon is by far the brightest thing in the night sky.But it has no light of its own.Moonlight is simply the Sun’s
light reflected off the white dust on the Moon’s surface.

4. WHAT IS A LUNAR ECLIPSE?

Ans: As the Moon goes around the Earth,sometimes it passes right into Earth’s shadow, where sunlight is blocked off. This is a lunar eclipse. If you look at the Moon during this time, you can see the dark disc of the Earth’s shadow creeping across the Moon.

5. WHAT IS THE MOON?

Ans: The Moon is the Earth’s natural satellite. It has circled around the Earth for at least four billion years. It is a rocky ball about a quarter of Earth’s size and is held in its orbit by mutual gravitational attraction. Most scientists believe that the Moon formed when, early in Earth’s history, a planet smashed into it. The impact was so tremendous that nothing was left of the planet but a few hot splashes thrown back up into space.Within a day of the smash, these splashes had been drawn together by gravity to form the Moon.

6. WHAT IS A HARVEST MOON?

Ans: The harvest moon is the full moon nearest the autumnal equinox (when night and day are of equal length). This moon hangs bright above the eastern horizon for several evenings,providing a good light for harvesters.

7. WHY DOES THE MOON LOOK LIKE CHEESE?

Ans: The moon looks like Swiss cheese because it is full of holes and can appear yellowish. The holes are craters in the surface created when it was bombarded by huge rocks early on in its history.

8. WHAT IS A NEW MOON?

Ans: The Moon appears to change shape during the month because, as it circles the Earth, we see its bright, sunny side from a different angle. At the new moon, the Moon lies between the Earth and the Sun, and we catch only a crescent – shaped glimpse of its bright side. Over the first two weeks of the month, we see more and more of the bright side (waxing) until full moon,When we see all its sunny side. Cover the next two weeks, we see less and less(waning), until we get back to just a sliver-the old moon.

9. WHY DOES THE SEA HAVE TIDES?

Ans: The Moon’s gravity draws the oceans into an oval around the Earth, creating a bulge of water on each side of the world. These bulges stay beneath the Moon as the Earth spins round and so seem to run around the world making the tide rise and fall as they pass.

10. HOW LONG IS A MONTH?

Ans: It takes the Moon 27.3 days to circle the Earth, but 29.53 days from one full moon to the next, because the Earth moves as well. A lunar month is the 29.53 days cycle. Calendar months are entirely artificial.

 

 

 

 

 

♦Content of the Universe click here