Category Science

What is the difference between the fusion reactions up to the element iron and beyond?

Up to the element iron, the fusion reaction is exothermic and there is a net energy output which makes the star shine. Beyond this, the fusion reaction is endothermic and there is a net energy input at the expense of the internal energy of the star.

How are the heavier elements beyond iron produced in a star?

The heavier elements beyond iron are produced only in certain kinds of stars called supernovae where the very high energy inputs required to sustain the necessary endothermic fusion reactions are available.

Do all stars evolve into red giants, then into white dwarfs and ultimately into black dwarfs?

The Conventional ten stages of evolution are applicable only to stars that have a mass of up to a certain critical limit.

What is the Chandrasekhar Limit?

The limit of mass beyond which a star will not become a red giant is called the Chandrasekhar Limit after the Nobel Prize winning India born U.S. astrophysicist who first propounded this theory. The Chandrasekhar Limit can vary between 1.2 to 1.4 times the mass of the Sun, depending on certain conditions.

What happens to a star that has a mass exceeding the Chandrasekhar Limit?

When a star with a mass exceeding the Chandrasekhar Limit exhausts its supply of hydrogen, the inward force due to its gravitation is so tremendous that it undergoes an immediate inward collapse followed by a sudden heating of the core, resulting in a cataclysmic explosion that blows the star apart and hurls the fragment far out into space. A star that undergoes such an explosion and disintegration is called a supernova. (Plural: supernovae).

Will the Sun cease to shine?

The Sun, currently yellow, will appear red in the red giant stage, then white in the white dwarf stage and finally black in the black dwarf stage. When it becomes a black dwarf, the Sun will cease to shine.

How long will the Sun continue to shine in a stable fashion as at present?

About five to eight billion years more.

What will happen to the Sun after five to eight billion years?

The Sun will cease to be stable and will expand into a giant star categorized as “Red Giant”.

What is a Sun pillar?

A Sun pillar is an optical illusion of a vertically stretched image of the Sun, formed in a manner similar to mock Suns.

Can ice crystals in the clouds cause mock Suns and solar haloes similar to mock Moons and lunar haloes?

Yes. Mock Suns are also known as perihelia.

Is mankind doomed to extinction when the Earth becomes uninhabitable?

Hopefully by the time Earth becomes uninhabitable, mankind would have sufficiently progressed technology to leave the Solar System in spaceships and colonize other parts of the galaxy.

At what stage in the life of the Sun, will the Earth become uninhabitable?

When the Sun starts becoming a red giant, the Earth will become so hot that everything will start melting. Obviously, life on Earth will cease to exist.

What are sunspots groupings?

While migrating, it can be observed that certain sunspots move together and these are called sunspot groupings. Single spots are known but mostly they form in group or pairs. Pairs of sunspots are quite common and even larger groupings can be seen.

How can be measure the tilt of sun’s axis and the speed of rotation of the sun?

By observing the moment of sunspot on the surface of the sun, we can get an idea of axial tilt and rotational speed of the sun.

What are active areas of the sun?

Active areas of the Sun are the areas of large sunspot groupings and movement.

What is the significance of sunspots?

Sunspots are an indicator of the internal turmoil in the Sun. Hence, appreciable increase in sunspots indicates that there is a larger level of turmoil within the Sun.

What is the sunspot cycle or solar cycle?

The sunspot activity on the Sun increases and decreases periodically over a number of years. This is called the sunspot cycle or solar cycle.

What is the period of the sunspot cycle?

The period of the sunspot cycle is approximately 11 years.

What is the pattern of recurrence of the sunspot cycle?

The pattern of the years of maximum sunspot activity can be taken as 1979, 1990, 2001, 2012, etc. as a rough eleven year cycle.

What are the apparent and true solar cycles?

The apparent solar cycle is observed to be about 11 years.

However, studies of the magnetic fields of pairs of the magnetic fields of pairs of sunspots show that magnetic polarity also reverses every 11 years. The true period of solar activity is therefore 22 years or twice the apparent period.

When is the Sun said to be quiet?

The Sun is said to be quiet when very few sunspots erupt. For example, the Sun was relatively quiet from 1645 to 1715 and few sunspots cloud be seen during this period.

Does the sunspot cycle affect the Earth?

Over the sunspot cycle, or solar cycle, there is a slight change in the level of radiation emanating from the Sun as light, heat, etc. Hence, temperatures on Earth are slightly more when the Sun is more active. This may cause melting of the polar ice caps and change in climate on Earth.

Does the sunspot cycle have any influence human beings?

There seems to be an unexplained correlation between sunspot peaks and violence upon Earth.  It has been witnessed over many 11-year sunspot cycles that incidents of violence, murders, immolations, shootouts and accidents seem to be increasing with the number of sunspots.

What is migration of sunspots?

Sunspots do not generally remain in one place, but keep moving towards the solar equator. This is called migration of sunspots.

What is an ice age?

The unusually cold climate on Earth which accompanies a period when the Sun is quiet, is called an ice age.

Have there been any ice ages in recent times?

Ice ages occur cyclically over a long period of thousands of years. However, there was a mini ice age from 1400 to 1850 when the Earth’s climate became unusually cold.

What are sunspots?

Sunspots are comparatively dark areas on the Sun which appear in the form of spots on the Sun’s disc.

What causes sunspots?

Internal disturbances in the Sun’s magnetic field manifest themselves as sunspots on the Sun’s surface.

What is the temperature of a sunspot?

About 4,0000C which is cooler than the rest of the surface of the Sun. Hence, the sunspot appears as a dark patch, though it is really very bright.

How large are sunspots?

Some sunspots may even be five times larger than the Earth.

Are sunspots permanent?

No. Sunspot appears and disappear and also undergo change in size.

How powerful is the magnetic field at a sunspot?

The magnetic field at a sunspot is several thousand times stronger than Earth’s average magnetic field.

How long do sunspots last?

Small sunspots survive only for few hours, while larger ones may persist for a few months.