Re: Planets and Stars - an idea
- From: "Terence Nesbit" <TerryKidd@xxxxxxx>
- Date: Sat, 18 Apr 2009 04:45:25 GMT
"Paul Colquhoun" <newsposter@xxxxxxxxxxxxxxxxxxxx> wrote in message news:slrngugcog.tvr.newsposter@xxxxxxxxxxxxxxxxxxxxxxx
On Fri, 17 Apr 2009 05:54:39 GMT, Terence Nesbit <TerryKidd@xxxxxxx> wrote:
|
| "Paul Colquhoun" <newsposter@xxxxxxxxxxxxxxxxxxxx> wrote in message
| news:slrngubfb7.8sr.newsposter@xxxxxxxxxxxxxxxxxxxxxxx
|> On Wed, 15 Apr 2009 09:42:46 GMT, Terence Nesbit <TerryKidd@xxxxxxx>
|> wrote:
|> | I posted this on the scifi newsgroup, so maybe I will post it here since
|> a
|> | few of you were discussing the rotational effect of launches.
|> |
|> |
|> | "Terence Nesbit" <TerryKidd@xxxxxxx> wrote in message
|> | news:kqBAl.93782$4m1.88719@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
|> |>I had a discussion on the Sci-Fi Bulletin Board a while ago concerning
|> the
|> |>Earth and why it does/does not revolve around the sun. Recently I was
|> |>watching PBS and on came a science teacher talking about a red planet in
|> |>space that could be seen during March/April (or Feb/Mar) that is located
|> 65
|> |>million light years away.
|>
|>
|> Have you got a reference for this? Are you sure they said it was a
|> planet?
|>
|> Did they mention how hard it was/is to see?
|>
|>
|> |> In the prior discussion I had mentioned that the Earth does not
|> |> necessarily have to revolve around the sun because the Earth's tilting
|> |> could presumably guide the seasonal shifts. During the winter the sun
|> can
|> |> be seen at a lower angle than in summer, where it is almost directly
|> |> overhead. This being the case, what is the utility of the Earth
|> circling
|> |> the Sun?
|>
|>
|> Mainly it stops us from falling into the sun and vaporising.
|>
|>
|> |> After hearing about the red planet and star (called beetlejuice and
|> |> Andromeda I think, the latter I'm not sure about), why can the citizens
|> of
|> |> Earth see the same planet and star, year after year, from 65 million
|> light
|> |> years away? The Earth and that planet and star would have to be in the
|> |> same position, or a similar one, comparative to the Earth. Of course,
|> |> this realization can only lead to one conclusion, but here are a few:
|> |> a) both reach the same spot at the same time every year (rather chancy
|> if
|> |> you consider that everything moves in space, and the other Planets in
|> our
|> |> solar system circle the Sun at its own timetable;
|> |> b) Beetlejuice and the other planet/star do not move (again in
|> |> contradiction to everything else in space, as we know it);
|> |> c) Each has their own path that places them close to each other at
|> these
|> |> points, but neither circles the sun. This suggests that the Earth
|> doesn't
|> |> circle the sun. Of course this latter answer would suggest that the
|> |> planet and star may be seen from other points from Earth, or at a
|> greater
|> |> distance.
|> |
|> | Let me clarify one thing.
|> |
|> | Since the Earth tilts, it should be apparent that the four seasons
|> humans
|> | experience are due to that tilting, and not Earth's orbit around the
|> sun.
|>
|>
|> Actually, it takes both the tilt and the orbiting to get seasons. The
|> tilt always points in the same direction, so as earth orbits the sun the
|> hemisphere pointing towards the sun changes from the northern to the
|> southern, and back.
|>
|> Do you think that the direction of the tilt changes during the year?
|> Remember that the earth's axis of rotation always points to the North
|> Star. If the axis moved during the year, this would not be true.
|>
|>
|> | Let's consider a day. A day is one revolution of the Earth on its axis.
|> | The sun rises and the sun sets. So why is it so far fetched for the
|> tilting
|> | to control the seasons, it would fit. This does not mean that the Earth
|> | never circles the sun, just that it isn't done in one year. A year for
|> us
|> | is the beginning and completion of four seasons, or some variation
|> thereof.
|>
|>
|> Grab a couple of spheres (like a basketball and a tennis ball), mark the
|> north and south poles on the smaller one, and see what happens when you
|> keep the tilt the same while you move the small ball around the larger
|> one.
| Okay. For an example spin a top. When you look at the top spinning from
| the top of it, it is seemingly spinning in one spot (unless you can't get it
| to spin in one spot). Most times the top is moving to and fro and spinning
| around and around at the same time. I think this is what the Earth is
| doing.
The earth differs from a top in several respects:
1) The earth is more symmetrical (spherical vs pear or disk
shaped)
2) The earth is many orders of magnitude more massive
3) The earth is not in contact with a non-moving surface (or any
surface, for that matter).
Tops move and tilt due to friction with the surface they are spinning
on, and interactions with the earth's gravitation.
The earth's axis of spin points in the same direction (with respect to
the "fixed" stars) from day to day, season to season, and year to year.
This is, of course, an approximation. The axis of spin does move, but
*very* *slowly*, as befits a very massive object. The axis describes an
approximately circular path against the fixed stars every 26,000 years.
See http://en.wikipedia.org/wiki/Precession_(astronomy) for more
details.
| The Earth rotates daily, which is why we have day and night. The
| Earth also tilts, it moves from point a, let's say when the Sun is closest
| to 12:00, to point b, let's say to a 1:00 or 2:00 position during the
| winter. In between these points, the Spring and the Fall (both of which are
| known for cooler or more moderate temperatures), the Earth is either
| increasing or decreasing its angle in relation to the sun. On days during
| the fall and spring when the weather is unseasonably warm, most instances
| the Sun has jumped further towards 12:00, and once the weather cools again,
| it is again at a normal position between 12:00 and 1:00/2:00.
I'm not sure what you mean by describing the position of the sun by the
time of day.
| If the tilt were the same, the Sun would never be seen at two o'clock, but
Did you do the experiment with the 2 balls like I suggested? The
position of the sun at noon (and sunrise/sunset/etc) can and does change
as the earth orbits the sun *without* the earth's axis of rotation
changing direction against the fixed stars.
| one of the best test cases in law school concerns a car accident where the
| sun reflected off of a windshield. This was not solely because of the time
| of day. On some days the Sun may be seen crossing above one building, but
| during a different season, it crosses over a completely different building
| when you stand in the same spot. This is because the Earth has tilted
No. This is because the angle between the earth's axis of rotation
(always pointing at the pole star, Polaris) and the line between earth
and the sun has changed, due to the earth moving along it's orbit.
| (which is why the Sun shines on the Southern hemisphere during winter; if
| the tilt never changed but the Earth moved closer to the Sun, either the
| temperatures would be warmer across the globe, or the Earth is at a
| different point, lower during the summer months and higher during the
| window, to allow for this discrepancy.).
Yes, summer and winter are when that hemisphere is tilted towards or
away from the sun, respectively. This is also why the seasons are
reversed in the southern hemisphere, with respect to the northern
hemisphere. BUT, the direction of the tilt does not need to change.
Take the 2 ball experiment I mentioned. Mark one "end" of the small ball
as the north pole, the opposite point as the south pole, and draw the
equator between them. Tilt the ball so the north pole is angled slightly
towards one wall of the room you are in (earth is tilted by ~ 23.5
degrees). Call that wall of the room "polaris". Now move the small ball
in a circle around the large ball, always keeping the small ball tilted
towards the polaris wall. See how the north end of the ball is sometimes
pointed towards the large sun-ball, and sometimes pointed away from it?
That is how you get seasons, without having to expend the huge amounts
of energy that would be required to change the earth's axis of rotation
every year, instead of every 26,000 years.
| I just noted the show in passing almost (it came on while I was watching a
| Ms. Marple show, or in between episodes). At 65 million light years, I
| think it is hard to see. But maybe not, since it could be clearly seen in
| that monthly period. I do remember the person talking about the difference
| because both of the objects are red in color when they are seen. One is
| closer than the other, the star is closer I think.
So it may just be a garbled memory of a (possibly mistaken) popular
science spot.
--
Reverend Paul Colquhoun, ULC. http://andor.dropbear.id.au/~paulcol
Asking for technical help in newsgroups? Read this first:
http://catb.org/~esr/faqs/smart-questions.html#intro
In fact, you might be moving in the wrong direction. If you use one corner of a room as a pole, the ball would have to traverse East to West, or West to East, from that very point. That would mean the smaller ball would have to travel up and across the larger ball, not circle while maintaining its angle to polaris. Why? Because Polaris is fictionally situated in that corner, as opposed to what really occurs to the Earth where polaris is in the air, or in space. By making polaris a fixed point away from Earth, you have altered the dynamic. If you make polaris a dot on the ball itself, and move it around the larger ball, it would not alter very much, probably not even the amount of sun present.
Terence
.
- References:
- Planets and Stars - an idea
- From: Terence Nesbit
- Re: Planets and Stars - an idea
- From: Paul Colquhoun
- Re: Planets and Stars - an idea
- From: Terence Nesbit
- Re: Planets and Stars - an idea
- From: Paul Colquhoun
- Planets and Stars - an idea
- Prev by Date: Re: Planets and Stars - an idea
- Next by Date: Re: Solar Sats For Real?
- Previous by thread: Re: Planets and Stars - an idea
- Next by thread: Re: Planets and Stars - an idea
- Index(es):
Relevant Pages
|
Loading
