keplers law

so, the planets revolve around the sun in an elliptical orbit?
all the models I have seen show the orbits as circular.

This explains why we have summer and winter, and why mars is closer to us
now?

Thanks,
jo

(yeah, just trying to get a grasp of the basics)

"jojo" wrote in message
.. .
so, the planets revolve around the sun in an elliptical orbit?
all the models I have seen show the orbits as circular.

That's because many popular books have over-simplified diagrams.

This explains why we have summer and winter, and why mars is closer to us
now?

No to the first, yes to the second. The difference in the distance of the
earth from the sun in winter as compared to summer is negligible. The
seasons are actually caused by the tilt of the earth's axis. When it is
summer in the northern hemisphere, that hemisphere is tilted toward the sun.
When it is winter in the northern hemisphere, it is tilted away from the
sun. (Just the opposite is true for the southern hemisphere).

RM

Thanks for setting me straight on that!
What is the tilt? 32 degrees?
wow, a little closer or further away and this planet would be intolerable.

Did I read somewhere that because of the elliptical orbits of Neptune and
Pluto that they
actually change places in their relationship to the sun? meaning, sometimes
Pluto is no the farthest planet?

Thanks again Ron!

jojo

"Ron Miller" wrote in message
...

"jojo" wrote in message
.. .
so, the planets revolve around the sun in an elliptical orbit?
all the models I have seen show the orbits as circular.

That's because many popular books have over-simplified diagrams.

This explains why we have summer and winter, and why mars is closer to
us
now?

No to the first, yes to the second. The difference in the distance of the
earth from the sun in winter as compared to summer is negligible. The
seasons are actually caused by the tilt of the earth's axis. When it is
summer in the northern hemisphere, that hemisphere is tilted toward the
sun.
When it is winter in the northern hemisphere, it is tilted away from the
sun. (Just the opposite is true for the southern hemisphere).

RM

The Tilt is at 23.5 deg

Right on with Pluto and Neptune!
"jojo" wrote in message
. ..
Thanks for setting me straight on that!
What is the tilt? 32 degrees?
wow, a little closer or further away and this planet would be intolerable.

Did I read somewhere that because of the elliptical orbits of Neptune and
Pluto that they
actually change places in their relationship to the sun? meaning,
sometimes
Pluto is no the farthest planet?

Thanks again Ron!

jojo

"Ron Miller" wrote in message
...

"jojo" wrote in message
.. .
so, the planets revolve around the sun in an elliptical orbit?
all the models I have seen show the orbits as circular.

That's because many popular books have over-simplified diagrams.

This explains why we have summer and winter, and why mars is closer to
us
now?

No to the first, yes to the second. The difference in the distance of
the
earth from the sun in winter as compared to summer is negligible. The
seasons are actually caused by the tilt of the earth's axis. When it is
summer in the northern hemisphere, that hemisphere is tilted toward the
sun.
When it is winter in the northern hemisphere, it is tilted away from the
sun. (Just the opposite is true for the southern hemisphere).

RM

The Tilt is at 23.5 deg

Right on with Pluto and Neptune!
"jojo" wrote in message
. ..
Thanks for setting me straight on that!
What is the tilt? 32 degrees?
wow, a little closer or further away and this planet would be intolerable.

Did I read somewhere that because of the elliptical orbits of Neptune and
Pluto that they
actually change places in their relationship to the sun? meaning,
sometimes
Pluto is no the farthest planet?

Thanks again Ron!

jojo

"Ron Miller" wrote in message
...

"jojo" wrote in message
.. .
so, the planets revolve around the sun in an elliptical orbit?
all the models I have seen show the orbits as circular.

That's because many popular books have over-simplified diagrams.

This explains why we have summer and winter, and why mars is closer to
us
now?

No to the first, yes to the second. The difference in the distance of
the
earth from the sun in winter as compared to summer is negligible. The
seasons are actually caused by the tilt of the earth's axis. When it is
summer in the northern hemisphere, that hemisphere is tilted toward the
sun.
When it is winter in the northern hemisphere, it is tilted away from the
sun. (Just the opposite is true for the southern hemisphere).

RM

"jojo" wrote in message
. ..
Thanks for setting me straight on that!
What is the tilt? 32 degrees?
wow, a little closer or further away and this planet would be intolerable.

Did I read somewhere that because of the elliptical orbits of Neptune and
Pluto that they
actually change places in their relationship to the sun? meaning,
sometimes
Pluto is no the farthest planet?

Neptune's orbit is almost circular, most planets have nearly circular
orbits, the exceptions are mercury and Pluto. Yes, when Pluto is around its
perihelion (closer to the sun), its orbit is inside the orbit of Neptune.
Last time that Pluto was closer to the sun than Neptune was from 1979 to
1999, next time will be from about 2228 to 2248.

Guillermo

"jojo" wrote in message
. ..
Thanks for setting me straight on that!
What is the tilt? 32 degrees?
wow, a little closer or further away and this planet would be intolerable.

Did I read somewhere that because of the elliptical orbits of Neptune and
Pluto that they
actually change places in their relationship to the sun? meaning,
sometimes
Pluto is no the farthest planet?

Neptune's orbit is almost circular, most planets have nearly circular
orbits, the exceptions are mercury and Pluto. Yes, when Pluto is around its
perihelion (closer to the sun), its orbit is inside the orbit of Neptune.
Last time that Pluto was closer to the sun than Neptune was from 1979 to
1999, next time will be from about 2228 to 2248.

Guillermo

jojo wrote:
Thanks for setting me straight on that!
What is the tilt? 32 degrees?
wow, a little closer or further away and this planet would be intolerable.

23.5 degree tilt - that which you see in standard Earth globes in school or the
library. And we actually do get a little closer and a little farther from the
Sun over the period of one year - closer in January and farthest in July.

That elliptical nature of our orbit and that of Mars is why this recent
opposition was so close. The orbits are not nested ellipses of the same
eccentricity, though they are nearly circular (which is why they are portrayed
that way in textbooks and science programs. We just passed our far point from
the Sun this past July (first week), while Mars was approaching its near point -
thus, we are closer to it than two years ago when the same was not true.


Did I read somewhere that because of the elliptical orbits of Neptune and
Pluto that they
actually change places in their relationship to the sun? meaning, sometimes
Pluto is no the farthest planet?

Yes, so that from 1979 to 1999, Pluto was closer to the Sun than Neptune.

jojo wrote:
Thanks for setting me straight on that!
What is the tilt? 32 degrees?
wow, a little closer or further away and this planet would be intolerable.

23.5 degree tilt - that which you see in standard Earth globes in school or the
library. And we actually do get a little closer and a little farther from the
Sun over the period of one year - closer in January and farthest in July.

That elliptical nature of our orbit and that of Mars is why this recent
opposition was so close. The orbits are not nested ellipses of the same
eccentricity, though they are nearly circular (which is why they are portrayed
that way in textbooks and science programs. We just passed our far point from
the Sun this past July (first week), while Mars was approaching its near point -
thus, we are closer to it than two years ago when the same was not true.


Did I read somewhere that because of the elliptical orbits of Neptune and
Pluto that they
actually change places in their relationship to the sun? meaning, sometimes
Pluto is no the farthest planet?

Yes, so that from 1979 to 1999, Pluto was closer to the Sun than Neptune.

Thanks for setting me straight on that!
What is the tilt? 32 degrees?
wow, a little closer or further away and this planet would be intolerable.

Did I read somewhere that because of the elliptical orbits of Neptune and
Pluto that they
actually change places in their relationship to the sun? meaning, sometimes
Pluto is no the farthest planet?

Thanks again Ron!

jojo

"Ron Miller" wrote in message
...

"jojo" wrote in message
.. .
so, the planets revolve around the sun in an elliptical orbit?
all the models I have seen show the orbits as circular.

That's because many popular books have over-simplified diagrams.

This explains why we have summer and winter, and why mars is closer to
us
now?

No to the first, yes to the second. The difference in the distance of the
earth from the sun in winter as compared to summer is negligible. The
seasons are actually caused by the tilt of the earth's axis. When it is
summer in the northern hemisphere, that hemisphere is tilted toward the
sun.
When it is winter in the northern hemisphere, it is tilted away from the
sun. (Just the opposite is true for the southern hemisphere).

RM