by Ron Kurtus
You can read them to further your understanding of the subject.
|Moon||How does the moon rotate around the earth?||USA|
|Moon Phases||Exactly what day a new moon falls on||USA|
|Multiple Universes||Questions about multiple universes||The Netherlands|
|The Earth||Why is the Earth spherical and not flat?||Tanzania|
|General Topics||Send me books on astronomy and relativity||Ethiopia|
|General||What caused the initial motion in the very first atom?||USA|
|Our Moon||Why is the Moon called the Earth's only satellite?||Philippines|
|General||Please send all the astronomy information||India|
|Resources||Wnat websites on astronomy||India|
|General||Orbit page missing||USA|
How does the moon rotate around the earth?
January 30, 2013
how does the moon rotate around the earth
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.
Exactly what day a new moon falls on
Topic: Moon Phases
August 28, 2012
I'm struggling with knowing exactly what day a new moon falls on. I know what usno navy says but my rabbi keep telling me something different.is the next new moon on September 16 or another time?
chris - USA
According to the USNO Phases of the Moon, the next new moon would be on September 16.
Although your rabbi may know about astronomy, I would trust the USNO, since that is their business.
Questions about multiple universes
Topic: Multiple Universes
August 23, 2012
I've read the page of 'Theory of Multiple Universes' with much interest. Some questions arose while going through it. I would be very grateful if you could share some light on some:
1) If our universe was made up in a multiverse, then can't the same questions regarding the start of universe, still be asked about the multiverse? So shouldn't we still ask ourselves how then the multiverse started? Doesn't this make the multiverse the same thing as the universe? (I am also asking the last question because you write that universes might affect force fields of other universes and that there are possible distances between them – as far as I understand these conditions can only be met in one universe)
2) How can there be a distance between universes if distance (space) is only existing within a universe?
3) It is written that the universe is 13,5 billion years old and that it is 156 billion light years wide. Then this would mean that the universe is expanding faster than the speed of light... I wonder if you can deduct this from those two premises, because it could also be that in the early days of the universe it was expanding very rapidly compared to nowadays and then now it does not have to be expanding faster than the speed of light. Am I right with saying that above deduction does not hold or am I missing something? (I know that nowadays the expansion of the universe is said to accelerate, which means that indeed that happens with a greater speed than light, and I know that a universe expanding is something else than matter travelling over space).
4) The answer given to ‘What is beyond the existing outer edge of the Universe?’ is according to the text ‘Many astronomers believe it is just empty space or nothing at all.’ I highly doubt that. From what I have read astronomers usually see the universe as all that exists and if you’d be at the ‘edge’ of the universe it should be really all there is. If there would be empty space behind it, then that is part of the universe as well. Most think in higher dimensions than the famous 3D. The universe could very well be curved in a non-3D way that would make the edge be a sort of loop to the universe itself. I can’t really explain it well, but maybe see it as Escher’s waterfall. His waterfall does not end at the edge because it simply loops into itself. So I tried to say that the universe according to astronomers is limited, but has no boundaries. There is no edge. So my question regarding this is if most astronomers really believe in a void beyond the edge of the universe, or if they believe that the universe has no edge?
5) I don’t think I get the Multiverse theorem. If universes overlap due to expansion, what does this mean? They become one? In what way do they overlap? In distance? Doesn’t that make the Multiverse one universe then?
6) How do you define distance if distance exists between universes in which all existing is included? It seems contradictive. Maybe I am making assumptions there are not in place? I just don’t understand how one can speak of distance between universes if distance seems to be one of those things that is existing or maybe needs something to exist because a distance is always between. If two universes exist and hence one can speak of distance between them, then what’s the difference between a universe and a multiverse? Is this a definition problem?
7) If only this universe can be measured (or we can have information about it, so to say), then how do you test/prove that other universes might be there? (if it is to explain things like the accelerated expansion of the universe, then how does this theory sound any better than the old idea of a God that created the universe and made it that way that it expands faster and faster?)
Thank you for showing interest in my pondering,
Kim - The Netherlands
With the concept of a multiverse or multiple universes, the various universes will start with a "big bang" of their own, just as our Universe started. However, the forces created from such "explosions" could influence or affect neighboring universes.
Light from nearby universes would probably be too faint to detect. Also, there is the consideration that the various universe have different forms of matter and energy.
Space and time are interesting concepts and probably are not confined to our Universe but extent throughout the Multiverse. Likewise with distance or separation between objects.
There are several versions of estimations of the width of the Universe. Some imply that expansion is faster than the speed of light. The best explanation I've seen is that dim galaxies at the edge of the observable Universe seem to be 13.5 billion years old. Light traveling from them would then take 13.5B years to reach us, and thus the radius of the observable Universe is 13.8 billion light-years.
I would define the edge of the Universe as the edge of matter from the Big Bang. Beyond that would be just space or perhaps other universes.
The distance between galaxies in our Universe is usually measured in terms of the length of time it takes light to travel the separation.
A good question is if other universes have the same physical laws. Perhaps there are different forms of energy.
The big thing is that the concept of multiple universes or multiverses is highly speculative. Although based on measurements, even the size and age of our Universe is guesswork.
Why is the Earth spherical and not flat?
Topic: The Earth
June 21, 2012
why earth is said to be in spherical shape and not flat?. Why other planets do not support life?
linus - Tanzania
When the Earth and other planets were formed, they were hot liquids. The internal forces cause liquids to take the shape of a sphere, like like with a raindrop.
When the Earth cooled and solidified, it remained in a spherical shape. Note that a flat shape would be unstable and inefficient.
Life as we know it requires an atmosphere of Oxygen and mild temperatures. Some plants are too hot and others are too cold. However, they may have forms of life that we do not yet recognize.
Send me books on astronomy and relativity
Topic: General Topics
June 11, 2012
Can you send me some books on astronomy and relativity?
Mikon - Ethiopia
I'm sorry but we cannot send you any books. However, you have use our lessons to get some of the information you need.
I am adding to the material all the time and will soon have e0books on the subject.
What caused the initial motion in the very first atom?
March 26, 2012
What caused the initial motion in the very first atom?
Joe - USA
The Big Bang Theory says that all atomic particles were highly compressed together and then exploded outward about 13 billion years ago. Particles clumped together after the explosion to form atoms and then later stars and galaxies.
See Big Bang Theory
Why is the Moon called the Earth's only satellite?
Topic: Our Moon
March 1, 2012
Why the moon its also called the earth's only satellite?
ricarose - Philippines
The Moon is the Earth's only natural satellite. However, countries have put numerous artificial satellites up into orbit around the Earth.
Please send all the astronomy information
February 27, 2012
please send all the astronomy information to me .and related best books.
zubair - India
See out section on Astronomy for information.
Each lesson has listing of books.
Best wishes for success in your Astronomy studies.
Wnat websites on astronomy
October 25, 2011
I love learning from your site.
Can you give me some other FREE websites from where I can gain knowledge about astronomy?
And PLEASE, don't think that your website is not enough for me.
I just love your website!
Priyam - India
Orbit page missing
October 19, 2011
A course website I help maintain was linking to a page on your website but the link now returns a page not found message. The page was at your school for champions domain followed by the path:
Has the material moved? In particular our website referred to a demonstration of a satellite revolving around the Earth. If you would let me know where that moved I would appreciate it.
Linda - USA
If I remember, that was a simulation of a satellite in orbit as a Java app. The page was from about 2005. But unfortunately, the application was not working as it should, so I removed it.
Usually, I provide a link to a page that has been moved and keep that link available for a few years.
If such an animation of an object in orbit is of interest to you and your students, I might be able to add something like that to the site. Let me know.
Sorry about the inconvenience.
Hopefully, this reader feedback has helped provide information about Astronomy issues.
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