 |
Astronomy newsletter November 2009.
|
|
 |
|
|
|
Although we had some cloudy evenings lately, which makes stargazing
difficult, it still rewards to look up at the night sky. |
|
Jupiter shines bright, shooting stars can be seen and the constellation of
Orion, the mighty hunter, is on the rise. |
|
|
| Our Solarsystem. |
|
| A brief
overview of our solarsystem: Earth is the third rock from the Sun. |
| The
planets, in order starting from the Sun are; Mercury, Venus, Earth, Mars,
Jupiter, Saturn, Uranus and Neptune. |
| From
these the first four are "rocky" planets like Earth, the other four are gas
giants. |
| Pluto
is no longer considered a planet but is called a dwarf planet. |
| Between
Mars and Jupiter you find the asteroid-belt, which is believed to be the
remains of when the planets were |
|
formed. Outside the path of Neptune you find
icy bodies and this is called the Kuiperbelt, named after the Dutch |
|
astronomer Gerard Kuiper who discovered it. |
|
 |
|
|
| |
| |
| |
| |
| |
| |
|
|
|
|
|
top |
Jupiter. |
|
Jupiter
is still dominating the nightsky. |
|
This
giant gasplanet, 300 times the size of our Earth, is the largest in our
solarsystem. |
|
Jupiter
has 63 moons and with a moderate telescope (75 mm) one can see the four
Galilean moons; Callisto, Europa, |
|
Ganymede and Io, so called because they were discovered by Galileo Galilei. |
|
 |
The distance from the Sun to Jupiter is 5,2
AU (Astronomical |
|
Unit). 1 AU is the distance between the Sun
and the Earth, |
|
which is about 150
million km. |
|
|
|
|
|
If traveling by car at an avarage speed of
120 km/hour it would |
|
|
take you about 600
years to reach Jupiter. |
|
|
This does not
include stops so you better pack enough food! |
|
|
|
|
|
Jupiters great red
spot, first noticed in 1664, is a giant storm, |
|
|
about four times
the size of our Earth. |
|
|
|
|
|
Galileo Galilei
(1564-1642) |
|
|
| |
It was
an Italian scientist, arguably the greatest astronomer who ever lived, who
discovered and published numerous |
|
|
proofs
that the Sun is the centre of the solarsystem. In 1609 (yes, 400 years ago
and that is why this is the international |
|
|
Year of
Astronomy), hearing rumors of a newly invented Dutch spyglass, Galileo
invented a much more powerful |
|
|
version, the telescope and... aimed it at the
heavens. |
|
|
|
|
|
|
|
He discovered that the Moon was not perfectly
smooth, as held by the church, but was covered in mountains and valleys
|
|
|
and was pockmarked with craters. He also
discovered and observed four of Jupiters moons. |
|
|
In 1632 he published "Dialogue on the Two
Chief World systems" and because of the contents, defending his view that
|
|
|
the Earth orbitted the Sun and was not the
centre of the stars and planets, he was tried by the Inquisition, found |
|
|
"vehemently suspect of heresy", forced to recant and spend the rest of hiss
life under house arrest. |
|
|
In 1984
Galilei was fully rehabillitated by the Roman Catholic Church. |
|
|
|
|
|
|
|
|
|
top |
Shooting stars. |
|
|
The popular name shooting stars refers
to a meteorid, entering the Earth's atmosphere and burning up. |
|
|
A
meteorid is a tiny piece of matter in space, from the size of a grain of
sand up to a small boulder. |
|
|
Many of
them are small chips of rock or iron, broken off their larger cousins the
asteroids. |
|
| |
When
the meteorids collide with the upper athmosphere, it's high velocity causes
a brief glow in the air as it passes |
|
| |
through. Sometimes the rock is big enough that some of it makes it all the
way to Earth and this rock is then called |
|
| |
a
meteor. |
|
|
|
|
|
When
the Earth's orbit passes through an area with lots of meteorids a meteorid shower can be seen. |
|
|
Between
12 and 21 November the Leonids can be seen, so called because they seem to
originate from the sign Leo, at |
|
|
around 4 in the
morning. |
|
|
|
If you
have missed the Leonids (and clouds did spoil most of this event) don't
worry, they will be back again same time |
|
|
next
year. If you can't wait that long, in December we can see the Phoenicids and
the Geminids. |
|
|
|
 |
|
|
|
|
| |
Orion |
|
|
The description of Orion as a giant and a
hunter comes from |
|
|
the Greek
mythology. In one of the stories Orion became |
|
|
very arrogant and boasted to kill all the
animals on Earth. |
|
|
The Gods were furious when they heard this
and send a |
|
|
scorpion to kill
him. |
|
|
|
|
|
Orion and the
scorpion fought a whole day and they could |
|
|
not defeat
eachother. Then at night Orion went to sleep |
|
|
and the scorpion
stung him. Before he died Orion killed |
|
|
the scorpion. |
|
|
The
Gods placed them among the stars but far apart and untill now you can see
when Orion sets in the West, Scorpius |
|
|
rises
in the East. |
|
|
|
|
|
top |
In
Orion you find Betelgeuse, a red supergiant star. If this star would replace
our Sun, it would encompass the orbit of Mars! |
|
|
|
|
| |
Other
prominent constellations which can be seen this time of year are Taurus and
Pegasus. |
|
|
Taurus |
|
|
|
 |
Northwest of Orion
you find Taurus, the bull. |
|
|
The eye of Taurus
is Aldebaran, a K-class orange giant, about |
|
|
40 times larger
then our Sun and 350 times brighter. |
|
|
Alderbaran is 60
lightyears away, which means the light takes |
|
|
60 years to reach
us. Light travels at a speed of almost |
|
|
300.000 km/ second. |
|
|
|
|
|
The open
starclusters Hyades (V-shaped, forming the face of |
|
|
Taurus) and
Pleiades (with more then 500 stars) can be seen |
|
|
clearly with the
naked eye. The Hyades are about 150 lightyears |
|
|
away. The Pleiades,
also called the seven sisters after the 7 |
|
|
brightest stars,
are 440 lightyears away. |
|
|
above: the Pleiades |
|
|
|
|
|
|
|
Pegasus
|
|
|
|
In the
North, the body of the winged horse from Greek mythology is outlined by the
Great Square of Pegasus. |
|
|
|
|
|
In the
South the Small and the Large Magellanic Clouds can be seen. They appear to
be clouds but in fact they are sattelite |
|
|
galaxies to our
Milky Way. |
|
|
|
|
|
|
top |
November highlights: |
|
|
12-21
November: Leonids meteor shower |
|
|
16 November: new
Moon |
|
|
|
24 November: first quarter |
|
|
|
26 November: Uranus 6.0° South of the Moon |
|
|
|
40 minutes before sunrise Venus can be seen
in the East and is now called the "morning star" |
|
|
From about 23:00 you can see mars, the red
planet. |
|
|
|
|
|
|
| |
From
Balule: Clear skies ! |
|
|
