Jan 14, 2009

Weather on Other Planets

Wild, Wild Planets


We've seen the worst that Earth's climate can offer , but what if
you're an apocalypse junkie, and don't really want to pack your bags
and head to Kansas to cruise inside a tornado-chasing vehicle? If you
get bored with Earth's extremities, look up at the starry sky and
consider the other wicked, in fact simply hellish atmospheres available
there:

Hot, Fast and Furious!


Take for instance a vacation spot a mere 870 light years away. Whatever
your definition, WASP-12b is an unusual place. Discovered in April of
this year, it’s a large planet – 50% bigger than our own biggest world,
Jupiter – and a damned fast one.


How fast? Well, you know that Earth takes 365 days to go around our
comfortable yellow sun. But WASP-12b takes a fraction of that time … in
fact a 364th fraction of that time. WASP-12b orbits its sun in a little longer than one day.










WASP-12b is also a rather balmy planet.
Considered a “Hot Jupiter” world, a gas giant without a rocky surface,
its temperature has forced a lot of astronomers to rethink exactly how hot a planet can get.
Time to play that game again: how hot? Well, our previously mentioned
comfortable yellow sun has a surface temperature around 5,000 degrees
centigrade. WASP-12b is also a fraction of that... in fact only half of
that. WASP-12b has been measured at about 2500 degrees – one of, if not
the – hottest extrasolar worlds so far discovered.


Here is an artist's conception of how bright the illuminated side of
such planet might look - "roughly 500 times brighter than desert sand
dunes on a midsummer day" (on the left). Right image shows a
Jupiter-like planet in front of the HD 149026 star (more
info) -





Another distant, possibly temperate,
vacation destination is much closer, a mere 63 years away at the speed
of light. this world in the Vulpecula constellation is another big,
hot, and fast wonder - it's slightly bigger than our own Jupiter,
orbits every 2 or so days and has a registered temperature of around
700 degrees Celsius.


Why a lot of people are so thrilled about the world that can turn you
into a puff of ash if you so much as even cracked your starship’s door?






Many things can get astronomers all
atwitter: new stars, new worlds, new phenomena, and especially certain
colors showing up on a spectroscopic scan. Without getting too
technical, and not testing your patience any further, Giovanna Tinetti
(and later NASA) discovered those spectroscopic colors in HD 189733b:
water vapor, carbon dioxide, and methane – evidence of what could be some form of life. Though what kind of life could live on a world like HD 189733b is anyone’s guess.







Speaking about supersonic winds, there is enough hellish weather to be found inside our Solar System:

Saturn's Psychedelic Clouds


Saturn boasts winds up to 1,800 km per hour - whipping up wildly
irregular clouds, which are often enveloped by darkness: the huge
shadow of Saturn's ring system blocks sunlight for long time, over a
huge area. Look into the eye of a monster storm on Saturn: the image on
the left shows an 8,000 km area, big enough to swallow Earth.... the
right image shows a mysterious hexagonal storm cloud shape:










Such wave clouds are a regular feature on Saturn:







Don Dixon imagines what flying through Saturn's clouds may look like:







Some slightly-enhanced images show the coffee-colored atmosphere (looks like a tiramisu) -






The weather can be a concern, though, with supersonic winds whirling
around. And then, of course, there is Uranus, which has seasonal
patterns (each season lasts more than 20 years) that are entirely
messed up: the planet is tilted 98 degrees from the orbital plane! The
poles are actually getting more sunlight than the equator




New images of "tiger stripes" on the surface testify of such dynamics (a spreading and splitting of the existing surface) -







Jets of Enceladus: huge plumes erupt from giant fissures in the moon's surface -







"What causes and controls the jets is a mystery", NASA admits. If there
is evidence of water, then Enceladus will become the prime candidate
for providing a habitable environment... similiar to the oceans under
the surface of Europa (moon of Jupiter). Europa's mysterious hidden
ocean covers the whole moon and is 100 km deep - containing in total
more water than all Earth's oceans combined.




The Crab Nebula has a really crabby instability


Interstellar nebula clouds can sometimes display type of instability
(when two fluids of different densities interact with each other,
compounded by gravitational effects). Such "RT fingers" can be clearly
seen in the Crab Nebula, where the "expanding pulsar wind nebula is
sweeping up ejected material from the supernova explosion long ago".








Where's CNN when you need it?


Cold or hot, comfortable or not, the universe can be a very dramatic
place – and a very dangerous place if you should get caught in one of
its ‘dramatic’ events. Everyone knows about black holes and supernovas,
and some of you might have heard about neutron stars, quasars, and
hypernovas, but in a few billion years everyone – if anyone is still
around of course – will know all about our neighbor galaxy, Andromeda.


Galaxies, like our own Milky Way, come in a variety of shapes and
sizes, including elliptical, peculiar, or – in the case of our home
galaxy – a barred spiral. Like everything in the universe they’ve been
moving since the Big Bang, heading to an eventual Big Crunch (if
there’s enough mass in the universe to slow, stop, and eventually
reverse the expansion back into a supermassive black hole and then,
possibly, out again in another Big Bang), Heat Death (where everything
in the universe simply dissolves into a dull, gray, warm ‘blah’), or
one of the many other theories about the eventual fate of the Universe.









But one thing is known: sometime in the next two and a half billion years, our skies will become very interesting as our Milky Way galaxy collides with, and merges with, our neighbor Andromeda.
No one knows what will happen then, but if we’re around – maybe holding
‘hands’ with our friends from HD 189733b – the sight will truly be
something behold.


That is, if we’re around to enjoy it …








Another galactic collision captured in incredible detail

No comments: