Stars’ explosions

Distant supernovas are indicators of the history of

universe.  Gravitational Theory of Einstein says that

the expansion of the world is reducing.  What is the

reason for this phenomenon?  This process can not be

tested by our lifetime.  Because, it takes more than

the period of our life.  A new and wonderful technique

has significantly changed our theories.  In fact, it

is the application of telescope rather than a device

measuring time.  We observe close future and see past

because distances in space are very long.  Sometimes,

it takes millions of years to receive light from a

star.  In fact, we saw the world in its current

conditions. 

Astronomers can observe the stars’ explosions,

which are called “Supernovas” from distant

galaxies.  It is possible to measure the speed of

these supernovas via testing their color.  Their

distance from us is also measured by the intensity of

their light.  By observation of supernovas in

different distances and in various times in the past,

the evidences of the world’s expansion speed can

be obtained.  The normal view of the world indicates

that the world’s speed is decreasing.  Two

groups of scientists believe that the world’s

expansion is increasing, but why? 

One reason is that the space is in form of energy.

Einstein’s Gravitational Theory indicates; if

the world itself has energy, its expansion must have

high speed.  But no one knows what this new and

mysterious form of energy is.  The results of

supernovas’ studies are negotiable.  For

instance, it was possible to have soil among galaxies

and this condition reduces the light of these

supernovas.  But if the results are correct, the most

important challenge is to infer the world conditions,

properly.

 

What is the Blue Moon? When does it occur?

Each complete month has a legendary name in the United

States.  Because, the number of crescents occurs in a

year is not an integer (day for each complete rotation

of moon is 29.53*12).  This phenomenon occurs every

three years in a month.  In the meantime, full moon

occurs twice during the mentioned period.  The second

full moon in calendar month is called the “Blue

Moon”.  This phenomenon occurs on December 31,

1991, September 30, 1993 and July 30, 1996.  Can you

guess the other dates for such an event?

 

What happens if the Sun becomes a Black Hole? 

If the Sun becomes a Black Hole, the Earth and most of

the planets remain in their own place and do not

collapse in it.  We will see the Sun bearing less

light, producing interstellar dust and asteroids.

Ofcourse, some parts of its mass converts into energy

near the “Event Horizon”.

 

What is Light-Year and how long will it take? And what

is Parsec?

Light-Year, in astronomy, unit of length sometimes

used to measure vast distances. It is equivalent to

the distance that light travels in a mean solar year.

At the rate of approximately 300,000 km/sec (186,000

mi/sec), a light-year is equal to 9,461,000,000,000

km.

Parsec, in astronomy, unit of measurement used, along

with the light-year, for stellar distances. One parsec

is the distance to a star that shows a parallax, or

apparent shift in position when viewed from opposite

sides of the earth's orbit, of one second of arc. (The

word parsec is an abridgment of the words parallax and

second.) This distance is 30.86 trillion km (19

trillion mi). One parsec is equal to 3.26 light-years

and to 206,265 astronomical units.  Each astronomical

unit is the distance between the Sun and Earth.

Perhaps, the figure can assist.  Please attention,

each arc degree is equal to 60 minutes and each minute

is equal to 30 seconds.  The angle of top part of the

triangle is equal to an arc degree (it has not been

mentioned in the figure).