[Az-Geocaching] Mars Approaching (Warning: Off-Topic)
Trisha
listserv@azgeocaching.com
Sat, 02 Aug 2003 10:52:05 -0700 (MST)
Thanks Jim! Fascinating!
Trisha
On Thu, 31 Jul 2003 16:43:04 -0700 (MST), Jim Scotti wrote:
>
> Hey Trisha,
> Mars is putting on a great show these nights - bright and red. I
> saw it
> peeking through the monsoon cloudy skies last night for the first
time
> in a
> week or so! I'd recommend for all those interested to visit your
local
> planetarium/telescope and get a good look. Also, keep an eye out for
> a Mars
> Star Party that I'm sure the local amateur astronomy clubs will be
> putting
> on. They have much better equipment than most people and are usually
> more
> than happy to show off things in the night sky.
> The best time to view Mars is when it is at its closest which
> happens when
> the Earth and Mars line up on the same side of the sun. When this
> happens,
> it is called opposition. The orbits of both Earth and Mars are not
> perfect
> circles, so the distance to Mars during oppositions varies
> considerably.
> When Mars is near its "perihelion", at its closest approach to the
sun
> each
> Martian year to the sun (which is 687 Earth days long) it is only 207
> million
> kilometers from the sun but when at its aphelion, at its farthest
from
> the
> sun, it is about 250 million kilometers from the sun (compared to
> Earths
> average distance from the sun of about 150 million kilometers). By
> comparison, Earth's orbit is much more circular ranging from 147.5 to
> 152.5
> million kilometers from the Sun. So, whenever the Earth and Mars
line
> up,
> which happens about every 780 days, the distance between them can
vary
> between 100 million kilometers if Mars it near its aphelion and about
> 57
> million kilometers when Mars is near its perihelion when aligned with
> Earth.
> It just so happens that this next month, Mars will be near its
> perihelion
> when it passes through opposition so it will be near its closest
> possible
> approach to Earth and therefore bigger and brighter than during most
> other
> Martian oppositions, so enjoy the show! Also, Earth is close to its
> aphelion
> (which happens in July), so that makes a difference of a couple
million
> kilometers (small change compared to the affects of Mars eccentric
> orbit on
> the story, but significant enough).
> If you really want to see Mars up close, check out the Mars Global
> Surveyor webpage - there are lots of wonderful places that I'd like
to
> hide
> geocaches on Mars - imagine a hike to the bottom of Valis Marinaris,
a
> canyon
> larger than our Grand Canyon or to the top of Olympus Mons, the
largest
> mountain in the Solar System. Here's a URL that will allow you to
> browse
> through some of those wonderful pictures:
> http://mars.jpl.nasa.gov/mgs/ - if
> you click the top link labeled "MOC Images with Captions..." to see
> some of
> the best examples which are released as "pictures of the day". These
> pictures have really changed my view of Mars from one of a distant
> planet
> with images from earlier spacecraft that made it look a lot like our
> own moon
> looks through a telescope to an actual place that you could put
hiking
> boots
> on and go out and explore. Here's a few interesting images in
> particular:
>
> http://www.msss.com/mars_images/moc/2003/07/25/index.html - These are
> a bunch
> of sand dunes that look like fortune cookies and are all very similar
> in
> appearance.
>
> http://www.msss.com/mars_images/moc/2003/06/05/index.html - Mars has
> dust
> devils, just like we see here in Arizona. Here is a picture of the
> tracks of
> some dust devils across the Martian surface.
>
> http://www.msss.com/mars_images/moc/2003/06/11/index.html - Here are
> some
> gullies on the side of a crater wall.
>
> http://www.msss.com/mars_images/moc/2003/06/10/index.html - There's
> also
> frost on Mars, in this case, carbon dioxide frost near the Martian
> poles.
> And this is a real color image too!
>
> http://www.msss.com/mars_images/moc/2003/07/11/index.html - This is a
> view of
> a small canyon feature - is it a crack or water erosion?
>
> You can also find pix of Mars moon Phobos and a picture of the Earth
> and Moon
> as viewed from Mars if you look around a little bit on these
webpages.
> Some
> of the images are a bit big, but IMO, they are worth the wait for
> downloading
> and in any case, there are some thumbnails that you can see before
> starting
> the bigger downloads....
> Any of you geocachers have telescopes? It might make for a great
> event
> cache one of these nights if so. I don't have anything bigger than a
> spotting telescope these days - I guess I'm too spoiled using the
> bigger
> telescopes I use every month up on Kitt Peak.
>
> Jim.
>
> On Thu, 31 Jul 2003 trisha@brasher.com wrote:
>
> > Hey there Jim Scotti!
> >
> > Any info you can give us about this up coming astronomical event?
It
> > sounds pretty cool!! (With our luck, we will end the 5-year drought
> > with a huge monsoon season and have cloud cover for the next two
> > months!!)
> >
> > (SPOILER: for those of you who are preterbed by off-topic posts, I
> > posted this to the list on purpose because I... 1) wanted to ask
Jim
> > and 2) thought there might be a number of others on this list who
> > would be interested in astronomy. So, if you are not interested,
just
> > delete this and any other upcoming posts with "Mars" in the title.
> > Simple. Thanks)
> >
> > Trisha "Lightning"
> > Prescott
> >
> > INFO:
> >
> > Never again in our lifetime will the Red Planet look so
> > spectacular!
> >
> > This month and next Earth is catching up with Mars, an
> > encounter that will culminate in the closest approach between the
two
> > planets in recorded history. The next time Mars may come this close
> is
> > in 2287.
> >
> > Due to the way Jupiter's gravity tugs on Mars and perturbs
> > its orbit, astronomers can only be certain that Mars has not come
> this
> > close to Earth in the last 5,000 years but it may be as long as
> > 60,000 years. The encounter will culminate on August 27th when Mars
> > comes to within 34,649,589 miles and will be (next to the moon) the
> > brightest object in the night sky. It will attain a magnitude of
-2.9
> > and will appear 25.11 arc seconds wide. At a modest 75-power
> > magnification Mars will look as large as the full moon to the naked
> > eye.
> >
> > Mars will be easy to spot. At the beginning of August, Mars will
rise
> > in the east at 10 p.m. and reach its azimuth at about 3 a.m. But by
> > the end of August when the two planets are closest, Mars will rise
> > at nightfall and reach its highest point in the sky at 12:30 a.m.
> > That's pretty convenient when it comes to seeing something that no
> > human has seen in recorded history.
> >
> > So, mark your calendar at the beginning of August to see Mars grow
> > progressively brighter and brighter throughout the month.
> > Share this!
> >
> > No one alive today will ever see this again.
> >
> >
> > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> > "Although no one can go back and
> > make a brand new start,
> > Anyone can start from now and
> > make a brand new ending."
> > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> > ____________________________________________________________
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> > http://www.azgeocaching.com
> >
>
> Jim Scotti
> Lunar & Planetary Laboratory
> University of Arizona
> Tucson, AZ 85721 USA
> http://www.lpl.arizona.edu/~jscotti/
>
>
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