# Feedback Q&A on Astronomy

by Ron Kurtus

Readers have sent in a total of 302 comments and questions on Astronomy issues. They are listed according to date.

You can read them to further your understanding of the subject.

## List of next 10 letters

### Country

General Topics Wants to be an astronaut South Africa

Astronomical Distances Light year is not best for astronomical distances Turkey

The Earth Which way does the Earth rotate? New Zealand

Mars Where did Mars get its name? Philippines

General Why doesn't the Sun have an atmosphere? Uganda

General Topics Why can't big bang be a white hole? USA

General Topics Want to study Astronomy Rwanda

General Topics Why is the pulsating theory not popular? USA

General Date when article on Sun was published USA

Moon How does the moon rotate around the earth? USA

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First 10 letters

## Wants to be an astronaut

Topic: General Topics

### Question

November 1, 2013

Hi i'm in grade 11 and my biggest dream is to become an astronomar and i want to learn more. I always ador the NASA news.

Thuso - South Africa

24158

### Answer

It is great that you have a dream of becoming an astronaut. Many countries are starting to send people into space. However, there are requirements to fulfill to become an astronaut. You should have a college education in the sciences and be in good physical condition.

See details on NASA Astronaut Requirements for some information.

The European Space Agency lists their Training Requirements.

Also see South African Space Programme.

Best wishes in achieving your dream.

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## Light year is not best for astronomical distances

Topic: Astronomical Distances

### Question

October 24, 2013

About
Light year distances: ?t is said to be 1LY=9460730472580,8 km
So 400 Ly=400*9460730472580,8=3784292189032000 km.This to say,that since 400 years,years is accepted 365,25 days.Even for eternity years are accepted to be 365,25 days.No this not correct.Year's days quantity is variable.It has a parabolic graph shape,showing days quantity per real time.
Then big distances should be evaluated with Light day unit.
1 LD=25920000000 km and the totality of days within 400 years is
calculated,with integrals=145732 days.Then the real distance of an object said to be at 400 Ly,is wrong.It is at 145732 ligth day or at
3777363691182340,km.There is a clear difference between LY and LD.

NECAT - Turkey

24127

### Answer

The purpose of stating astronomical distances in light years or the distance light travels in an Earth year is for the sake of convenience, since stating the distance in kilometers would be cumbersome.

Yes, it is true that the Earth's year varies, but the resulting difference in distance is insignificance when you are considering the enormous distances in space. Basically, a light year is a good approximation of astronomical distance.

Also, using such a number as 9460730472580,8 km for a light year is not good science, since the number has too many significant places and implies a certain accuracy. The number should be rounded off and put in a scientific notation, such as 9.46E12 km.

A light day could be used to indicate distance, but note that the length of a day is not exactly 24 hour and also varies.

However, it is good that you are looking deeply into how these distances are stated. Best wishes in your Astronomy studies.

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## Which way does the Earth rotate?

Topic: The Earth

### Question

June 21, 2013

If the Earth spins counterclockwise on its axis as mentioned in the article wouldn't the Sun appear to rise in the West?

Rob - New Zealand

23798

### Answer

The Earth rotates on its axis from the West towards the East. Viewed from the North Pole, it rotates counterclockwise. However, in New Zealand, you might view it from above the South Pole, such that it rotates clockwise from that perspective.

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## Where did Mars get its name?

Topic: Mars

### Question

June 10, 2013

from where did gets mars name ?

hermie james - Philippines

23764

### Answer

Since Mars has a reddish glow, the ancient Romans related it to blood and named the planet after their god of war, Mars.

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## Why doesn't the Sun have an atmosphere?

Topic: General

### Question

May 6, 2013

Why do the sun has no atmosphere?

Kwemoi - Uganda

23669

### Answer

An atmosphere is a layer of gasses surrounding a planet or even star.

The atmosphere of the Earth is made up of air, including oxygen and nitrogen. The Sun also has an atmosphere, but it is made up of extremely hot gases, such as hydrogen and helium.

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## Why can't big bang be a white hole?

Topic: General Topics

### Question

May 3, 2013

why can't big bang be a white hole??

kritika - USA

23665

### Answer

While a Black Hole is an area in space where matter can enter but light and matter cannot escape, a White is just the opposite: Light and matter cannot enter but it can escape.

There are theories that the Big Bang came from a White Hole.

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## Want to study Astronomy

Topic: General Topics

### Question

March 20, 2013

How can i get to study astronomy on scholarship in Canada ? what are the most important subjects in order to study astronomy?

mpore - Rwanda

23552

### Answer

See Astronomy Scholarships in Canada for a small listing. It is a start.

Physical Science gives and overview of Astronomy. Physics, Astrophysics, and Chemistry are usually needed. Also, higher Mathematics courses are required.

Best wishes in becoming an Astronomer.

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## Why is the pulsating theory not popular?

Topic: General Topics

### Question

March 4, 2013

sir, i want to know that why is pulstating theory is not widely acceptable

kritika - USA

23518

### Answer

The three main theories of the behavior of the Universe are the Big Bang Theory, the Steady State Theory, and the Pulsating Theory.

In the 1920s, Albert Einstein believed in the cyclical or pulsating theory, but in 1934 it was proved that the theory fails because--according to the Second Law of Thermodynamics--entropy can only increase.

However, there are some new theories to explain the cyclical or pulsating view of the Universe. Still, the Big Bang theory seems more appealing to astronomers.

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## Date when article on Sun was published

Topic: General

### Question

February 19, 2013

When was your article on the Suns Characteristics published?

- USA

23211

### Answer

The date is right under the title: 11 April 2009

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## How does the moon rotate around the earth?

Topic: Moon

### Question

January 30, 2013

how does the moon rotate around the earth

- USA

23163

### Answer

Both the Moon and the Earth are in motion in space. The gravitational force between the Moon and The Earth causes the Moon to go in orbit around the Earth. Gravitation causes the centripetal force to keep it in orbit.

Likewise, the force between the Earth and the Sun keeps the Earth in orbit around the Sun.

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