Transcript February 2008

Welcome to
Starry Monday at Otterbein
Astronomy Lecture Series
-every first Monday of the monthFebruary 4, 2008
Dr. Uwe Trittmann
Today’s Topics
• Recent Advances in Astronomy –
Part II
• The Night Sky in February
Feedback!
• Please write down suggestions/your interests on the
note pads provided
• If you would like to hear from us, please leave your
email / address
• To learn more about astronomy and physics at
Otterbein, please visit
– http://www.otterbein.edu/dept/PHYS/weitkamp.asp (Obs.)
– http://www.otterbein.edu/dept/PHYS/ (Physics Dept.)
Recent Advances in Astronomy
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Data
Theory
Instruments
Space Flight
Space probes
Recent Advances in Astronomy:
Space flight
• X-price
• Moon-Mars initiative
• New Space Nations:
– China
– India
The Moon-Mars Initiative
• NASA website: “The Vision
announced by President
George W. Bush on Jan. 14,
2004, offers a "building block"
strategy of human and robotic
missions, beginning with
returning the Space Shuttle to
flight and completing the
International Space Station. It
calls for humans to return to
the moon by 2020 and
eventually explore Mars and
beyond.”
•http://www.nasa.gov/missions/solarsystem/explore_main.html
X Prize
• Peter Diamandis is the brains behind the X Prize Foundation, an
organization intent on spurring innovation in the development of
private low-cost space travel through competitions like the aviation
prizes of the 1920s and 1930s. The foundation’s $10 million Ansari
X Prize was won in October of 2004 by SpaceShipOne. It also
recently announced the WTN X Prize, a series of competitions that
will cover all areas of science and technology, the categories of
which are still being determined. In 1998, he co-founded Space
Adventures, a company specializing in space tourism packages for
the likes of Dennis Tito and Mark Shuttleworth.
Space Tourism
• Dennis Tito made headlines in 2001 when he
became the world’s first space tourist, paying $20
million to Russia for the privilege of visiting the
International Space Station for six days. The trip
was the fulfillment of a decades-long dream for
Tito, who had originally planned to visit Mir
before Russia decided to decommission the aging
space station.
{Space.com}
Spaceship One
• SpaceShipOne won the $10 million Ansari X Prize when
it became the first private craft to take a human into space
twice in a two week period. The plane was designed by
Burt Rutan and built by Rutan’s company, Scaled
Composites Inc. SpaceshipOne’s technology has been
licensed by Richard Branson's Virgin Galactic, with
flights scheduled to begin in 2007. Rutan is an advocate
of space travel “for the rest of us,” and envisions a future
in which people will have personal flight vehicles.
• {Space.com}
Spaceship 2
• Test flights this year?
• $200,000 to get to outer space
Orion Spacecraft
• “Apollo on steroids”
• Space shuttles schedule to retire by 2010
Orion orbits the Moon
Lunar Ascent
Recent Advances in Astronomy:
Theory
• Redefinition of “planets”
• Dark Matter and Dark energy
candidates
Pluto’s Demotion
• Since August 2006, Pluto is not a planet
anymore, but a “dwarf planet”
• The International Astronomical Union
(IAU) voted on a new definition of the term
“planet” at its triennial meeting in Prague
• There is hope: lots of astronomers are not
happy with the new definition, and could
vote to change it in 3 years …
Why is Pluto not a planet anymore?
– The Definitions
(1) A "planet" is a celestial body that:
– (a) is in orbit around the Sun,
– (b) has sufficient mass for its self-gravity to overcome rigid body forces
so that it assumes a hydrostatic equilibrium (nearly round) shape, and
– (c) has cleared the neighbourhood around its orbit.
(2) A "dwarf planet" is a celestial body that:
– (a) is in orbit around the Sun,
(b) has sufficient mass for its self-gravity to overcome rigid body forces
so that it assumes a hydrostatic equilibrium (nearly round) shape2,
– (c) has not cleared the neighbourhood around its orbit, and
– (d) is not a satellite.
(3) All other objects, except satellites, orbiting the Sun shall be
referred to collectively as "Small Solar System Bodies".
Cleaning up the
Neighborhood
• Small objects are forced
out of the inner Solar
System by gravitational
pull of bigger planets
• Small planetesimals
collide and form planets
-- or are thrown out!
Why should we change the
definitions?
• There were no clear definitions
• New data / new discoveries
– Many new trans-Neptunian objects found
– Many new exo-solar planets discovered
It’s the way of science: we build our view of the
world based on observations; if it is more
convenient we modify our theories, terms, etc. to
better represent the world around us.
Quaoar started it
• 2002 Quaoar Discovered
• Quaoar is a frozen world located in what is
known as the Kuiper Belt
• At 800 miles in diameter Quaoar is the
largest object found in our solar system
since the planet Pluto was discovered in
1930.
Soon more followed …
The candidates size-wise: Eris,
Pluto, Ceres (and Earth)
Two types of planets
Is the demotion outrageous? – Not
unprecendented!
• History of our view of the solar system
– Pre-1450 AD: Earth in center (not a planet!), 7
planets (including Sun & Moon!)
– Copernicus: Sun and 6 planets
– W. Herschel (1781): Sun and 6 planets (add Uranus)
– Piazzi (1801): Sun and 7 planets (add Ceres)
– A few years later: Sun and 11 planets (add 3 more
asteroids: Pallas, Juno, Vesta)
– 1846: a dozen planets (add Neptune)
This just
in:
Mercury’s
far side
• Until last
month, we
only knew
how 45% of
Mercury’s
surface
looks like 
Mercurians?
Unique Mercury: double-walled craters
MESSENGER flies through
Mercury’s Magnetosphere
Recent Advances in Astronomy:
Instruments
• Telescopes
– Adaptive Optics
– Segmented mirrors
– Twin and multiple telescopes
• Amateur Telescopes
– Goto technology
• Detectors
– CCDs
– digital cameras
– Particle detectors
Largest Operational Telescopes
• 10.4m Gran Telescopio Canarias La Palma, Canary Islands, Spain
– 28 46 N; 17 53 W, 2400 m, Observatorio del Roque de los Muchachos; segmented
mirror based on Keck
• 10.0m KeckMauna Kea, Hawaii,
– 19 50 N; 155 28 W, 4123 m, mirror composed of 36 segments
• 10m SALTSouth African Astronomical Observatory
– 32 23 S; 20 49 E; 1759 m, based on the HET design
• 9.2m Hobby-EberlyMt. Fowlkes, Texas
– 30 40 N; 104 1 W, 2072 m, very inexpensive: spherical segmented mirror; fixed
elevation; spectroscopy only
• 8.4m Large Binocular TelescopeMt. Graham, Arizona
– 32 42 N; 109 53 W, 3170 m, eventually will have a pair of 8.4-m mirrors giving the
light gathering of an 11.8m and the resolution of a 23-m8.3
• 8.4m Subaru, Mauna Kea, Hawaii
– 19 50 N; 155 28 W, 4100 Mnaoj
• 8.2m AntuCerro Paranal, Chile
– 24 38 S; 70 24 W, 2635m now operate independently in the future will be units of
Very Large TelescopeKueyenMelipalYepun
Telescopes under construction
• 21.4m(7x8.4m)Giant Magellan TelescopeChile,
– six off-axis segments plus one central segment form
one optical surface
• 16.4m (4x8.2m)Very Large TelescopeCerro
Paranal, Chileall four units now operational;
will be combined as an interferometer
• 14.6m (2x10m)Keck InterferometerMauna Kea,
HawaiiKeck I and II
• 8m LSSTCerro Pachon, Chileaka Dark Matter
Telescope; a fast wide field survey scope
Telescopes of the Future
• 100m OWL OverWhelmingly Large
Telescope
• 50m Euro50
• 42m E-ELT European Extremely Large
Telescope
New Telescope Design
Many small mirrors instead of one big one
Adaptive Optics
• Adaptive optics is a technology to improve the
performance of optical systems by reducing the
effects of rapidly changing optical distortion. It is
commonly used on astronomical telescopes to
remove the effects of atmospheric distortion, or
astronomical seeing. Adaptive optics works by
measuring the distortion and rapidly compensating
for it either using deformable mirrors or material
with variable refractive properties. (Wikipedia)
Adaptive Optics
Uranus w/o & w AO
Lick Observatory
laser guide star
The Night Sky in February
• Long nights, getting shorter!
• Winter constellations still high up: Cassiopeia,
Pegasus, Perseus, Andromeda, Pisces
 lots of open star clusters!
• Mars is visible most of the night, Saturn late at
night
Moon Phases
• Today (Waning Crescent)
• 2 / 6 (New Moon)
• 2 / 13 (First Quarter Moon)
• 2 / 20 (Full Moon)
• 2 / 28 (Last Quarter Moon)
Today
at
Noon
Sun at
meridian,
i.e.
exactly
south
10 PM
Typical
observing
hour,
early
February
Saturn
Mars
Star
Maps
Celestial
North Pole –
everything
turns around
this point
Zenith – the
point right
above you &
the middle of
the map
40º
90º
Due
North
Big Dipper
points to the
north pole
SouthWest
Perseus,
Auriga &
Taurus
with Plejades
and the
Double
Cluster
South
• Orion
• Canis
Major &
Minor
• Beautiful
open star
clusters
• Orion
Nebula
M42
South
-East
• Gemini
• Cancer
• M44
Beehive
(open star
cluster)
• Mars
East
Spring
constellations:
– Leo
– Hydra
M44 Beehive
(open star
cluster)
Saturn
Deep
South
Lepus
Columba
Puppis (part
of the former
Argo)
Horizon in Germany (50º lat.)
Mark your Calendars!
• Next Starry Monday: March 3, 2008, 7 pm
(this is a Monday
)
• Observing at Prairie Oaks Metro Park:
– Friday, February 15, 6:30 pm
• Web pages:
– http://www.otterbein.edu/dept/PHYS/weitkamp.asp
(Obs.)
– http://www.otterbein.edu/dept/PHYS/ (Physics Dept.)
Mark your Calendars II
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Physics Coffee is every Monday, 3:00 pm
Open to the public, everyone welcome!
Location: across the hall, Science 244
Free coffee, cookies, etc.