Astrophysics, Space Science, Planetary Science and
Christopher B. Siren
Astrophysics, Space Science, Planetary Science, and Cosmology
A word to the uninitiated: At first blush one might think that
Astrophysics, Space Science, and Planetary Science are all pretty much the
same thing, and indeed, they often wind up being lumped together under the
heading Astronomy. The main differences are that Astrophysics is the
study of everything outside the solar system and Space and Planetary
Science are pretty much confined to the solar system. Planetary Science
is the study of those solid and fluid bodies within the solar system, from
the size of a small rock, to something like Jupiter or even the Sun. It
has close ties to geology and meteorology. Space Science concerns itself
with the seemingly empty space between the planets and sun. It is the
realm of the Solar wind, charged particles and magnetospheres. All three
branches overlap in the study of our closest star, the Sun.
Megasites from NASA and associates
The Solar System
- The SEDS (Students for the
Exploration and Development of Space) site has an extensive
tour of The Nine Planets
- Calvin J. Hamilton's Views of the Solar
System is another good collection of images and information.
- The SOHO spacecraft
provides a report of Solar
Weather conditions which includes several views the sun over a number
of different sets of wavelengths.
- The Sun Today: SHINE Directory to the Latest Solar
Images and Interplanetary Data.
- Big Bear Solar Observatory
at Big Bear Lake, CA provides a number of current images of the Sun in a
number of wavelengths, as well as magnetograms.
- As an undergrad, I did one of my theses on Venusian
volcanoes, using data collected by Magellan.
- Also check out the Magellan Image Sever
from MIT's Center for Space Research.
- and NASA's
Magellan Mission to Venus page.
- Glen Newton and Paul Budkewitsch present F.O.V. Face
of Venus includes descriptions of the types of features found on Venus
as well as searchable databases about Venusian craters and coronae.
Prospector was launched in January of 1998. This spacecraft finished
its mission in July 1999, by crashing into a lunar crater near the
south pole in an attempt to see if there is any water there.
- In 1996, Clementine also visited the
moon and found evidence of ice in a polar crater.
- Eric M. Jones has assembled a Apollo Lunar
Surface Journal documenting the surface portions of the manned
missions to the moon from 1969 to 1972. Included are the transcripts
between the astronauts and Houston, numerous images, and commentary on
what was done and why.
- In the practice of science it is good to remain skeptical of
assertions made by others until one sees if those assertions are backed up
by solid justifications and proof. Some folks have taken the skeptical
portion of this attitude with regard to the Apollo Moon landings, but
haven't really examined the proof that astronauts did indeed land on the
Moon. Michael Shermer of Skeptic magazine looks at the reasons
why folks might think the lunar landings were faked and counters those
arguments in this "Moon Hoax"-
- Set to launch in 2003, ESA's Mars Express will put the
Beagle2 lander on the planet.
- Jim Bell has
some interesting pages on Mars and NEAR
- Woohoo! Mars
Pathfinder landed on that planet on July 4th, 1997.
- Because of the high load expected around the landing date,
JPL has let SGI put up this Pathfinder
- The Mars
Global Surveyor arrived in September of 1997 and began mapping that
planet in March of 1998.
- The geological features in the Cydonia Region
are quite interesting and include what has been called the "face on Mars".
The above web page presents the raw and processed images of that region from
Mars Global Surveyor.
- This page on the
Face on Mars by Malin Space Science Systems presents some of the same
images in a clearer format than above.
- In early August, 1996 a team of NASA and Stanford scientists
held a news conference about their findings from an asteroid centering around
the possibility that there was once life on Mars. JPL's mirror site, Ames's mirror site Johnson Space Center's mirror
- Transcripts of that news conference and other life on Mars
related links can be found at the Federation of American Scientists
- In the 1970's the Viking spacecraft orbited and landed on Mars.
You can use these Mars Atlases and image finders to search the images obtained from
- As Galileo is to Jupiter, Cassini is to Saturn.
Launched in late 1997, Cassini is due to arrive at Saturn in 2003 and
drop a probe into the atmosphere of Titan, Saturn's largest moon.
- NEAR - Near
Earth Asteroid Rendezvous flew past 253 Mathilda and snapped some
cool pictures then orbited and later landed on the asteroid Eros.
- The Planetary Data System,
Small Body Node provides information, including ephemeris data, about
Asteroids and Comets.
- Dr. David Williams maintains the NSSDC
Asteroid Home Page.
- David Jewitt maintains an informative page on the Kuiper Belt a
collection of icy bodies beyond the orbit of Neptune.
- Douglas Hamilton presents a page on Solar System
Collisions which includes an applet which lets you input data on how
fast, how large and what composition your impacting body will be and then
shows you the results with images from actual craters and some artistic
- The Comet Observation Home
Page maintains information on currently visable comets as well as
having old comet images.
- In the Summer of 2000, Comet Linear made its closest approach to
the sun and began to
- Russel Sipe has assembled a site on Comet Hale-Bopp - which wowed us
in March, April, and May of 1997.
- In March of 1996,
Comet C/1966 B2
(Hyakutake) was a brilliant show. Quite visible to the naked eye, it
passed within one tenth of an AU of the Earth.
- Charles Kowal discovered the icy body Chiron in 1977,
but it wasn't until 1988 that a cometary tail was observed, confirming
that it was a comet and not an asteroid.
Cometary Magnitude Analyzer
- The New Solar System, ed. Beatty, J. Kelly and Chaikin,
Andrew, Sky Publishing Corporation, Cambridge, Massachusetts, 1990 (There
is also a more recent edition). This wonderful book collects articles on
the Sun, the planets, comets, asteroids and other features of our solar
system written by top planetary scientists. Still, the technical jargon
is minimal and kept at a Discover magazine level. It also contains
several beautiful photos and color charts which help illustrate the
concepts within. I first used this in an introductory level planetary
science course at MIT, but it would be a good resource for high school
students writing a term paper in earth science or astronomy.
Beyond the Solar System
- Robert Nemiroff and Jerry Bonnel at Goddard Space Flight Center
present the Astronomy Picture
of the Day, along with archives of past pictures. The archives are
organized by topic and each picture's page has an informative caption.
- Check out the Latest from the
Hubble Space Telescope, or visit their library of Pictures.
- The Very Large Telescope (VLT) at the European Southern Observatory in Chile is
the largest optical array of telescopes right now (four 8.2 m mirrors
acting in concert as a 16 m telescope).
- The High Engergy
Astrophysics Science Archive Reasearch Center (HEASARC) at NASA's
Goddard Space Flight Center (GSFC) details their numerous missions &
spacecraft, and presents an informative outreach section.
- VSOP the Very long
baseline interferometry Space Observing Program includes an 8m radio dish
in a highly eliptical orbit with a 21,000km apogee in addition to sites on
- The Far Ultraviolet Spectroscopic Explorer (FUSE) looks for deuterium (heavy
hydrogen) as a means of tracing the evolution of galaxies & the universe.
- CHANDRA, like the HST is
one of the Great Observatories in orbit about the earth. Whereas Hubble
looks mainly in the visible region of the spectrum, Chandra looks in the
higher energy, X-ray region of the spectrum.
- Another of the great observatories has had a lot of use back at
UNH. The Gamma-Ray Observatory's (GRO) Compton Telescope (COMPTEL) looked at the spectrum
of light at energies even higher than Chandra. A large part of its
mission is oriented around studying the enigmatic gamma-ray bursts. The
GRO was de-orbited and crashed into the Earth in June 2000.
- ESA's successor gamma-ray telescope is INTEGRAL>
- The satellite Hipparcos
has used the method of parallax to determine the position of, distance to,
and proper motion of thousands of nearby stars with the greatest accuracy
- One cool thing about the Hipparchos results is that they help
resolve the Globular
Cluster Age problem - the old distance calculations to Cephid
variables made Globular's seem closer and therefore older than we now find
them to be. They were thought to be older than the Hubble law prediction
for the age of the universe, but this conflict is not mostly resolved.
- There have been an awful lot of planets found around other
stars lately so JPL has established the
Exploration of Neighboring Planetary Systems homepage.
- Info on the nearby extra-solar planet discovered in June 1998 can
found here and
- The Electronic Universe project includes a page on the planet
discovered in orbit around 51 Pegasus. The physics
on this page is algebra based with a bit of statistics when discussing
whether or not the planet could maintain its atmosphere.
- Because of the low sensitivity of our current instruments, the
extra-solar planets we have found thus far tend to be very close to their
parent stars and very massive, thus earning them the nickname Hot Jupiters in
this Scientific American article and elsewhere.
- University of Manchester's Jodrell Bank Obsevatory has a nice
article on Neutron
- John Kolena collects a number of links to information about Black Holes on
- Sky Publishing,
publishers of Sky and Telescope put out weekly news releases inluding
highlights of the sky this week.
- Astronomy Magazine another
major amateur astronomy magazine.
- The Space Access
- Nick Strobel's Astronomy
Notes present a lengthy introduction to the subject as an online
version of his book of the same name.
- Gary Agranat presents Astronomy Homework
Help on a variety of subtopics, including a collection of links
geared particularly "for young minds".
Jonathan McDowell's Space Page contains links to a number of sites
including his weekly Space Reports.
Hawking's Universe was an excellent mini-series on PBS a few years back
featuring a number of astrophysicists and physicists. The companion website
has a number of articles on a wide variety of astronomy and physics related
- Sometimes the information we see about astronomy is just bad.
Sometimes the entertainment industry skimps on the science for the sake of
story and viewers buy into it, sometimes news crews make mistakes, sometimes
it's a long standing popular tradition. When Bad Astronomy strikes,
Phil Plait tries to correct it on this informative and entertaining site.
- As an undergrad, I took an observational astronomy seminar run by Steve Slivan.
He's got a nice collection of images of
Messier Objects taken from the 24" telescope at MIT's Wallace
- The Amateur Astronomy
Observers' Log has more images of a wide array of objects.
- For subscribers, there is net access to The Astrophysical
- There are a lot of Astronomy Sites on the
Internet and the web.
- Much of the research at UNH's
physics department centers on astrophysics and space physics.
- Then, there is the
astronomical Data Center of Strasbourg.
- Is anybody out there? The folks at SETIquest and SETI League Inc. are
trying to find out.
- sci.space.news (moderated)
- sci.astro (Beware the high volume)
- What can we determine about how the universe formed and how it
is structured? How do we figure this out? Ned Wright maintains a very
useful collection of Frequently
Asked Questions in Cosmology
- John Hawley and Katherine Holcomb provide web support for their
Foundations of Modern Cosomology including summaries of the
contents and relevant links.
- In 1980, Alan Guth introduced the Cosmic Inflation theory, a
refinement of the Big Bang theory. Guth introduces this theory in an
article originally for "The Beamline" in Was
Cosmic Inflation the 'Bang' of the Big Bang?
- Andre Linde has
helped modify and expand Guth's original theory and on his home page
describes the "Self Reproducing Inflationary Universe".
- John Gribbin author of several popular science books, presents Inflation
- When Albert Einstein first described General Relativity in 1915,
he included a cosmological
constant which kept the universe in his theory
from collapsing in on itself. Later observational evidence showed that the
universe was expanding as if from some initial explosion and not holding
some steady state as Einstein had assumed. This made the cosmological
constant unnecessary and Einstein considered it "his greatest blunder".
However, recent observational evidence suggests that the universe may be
expanding more rapidly than gravitational attraction should allow. This
has led many to suggest we may need to re-introduce the cosmological
constant and explain this repulsion that occurs over very large scales as
a consequence of vacuum energy a.k.a. "dark energy".
- This article from Science Beat describes
the SuperNova/Acceleration Probe might be used to find evidence of such
- Paul Preuss reports on dark
energy as originally described by Bahcall, Bahcall, Ostriker and
Steinhardt in a 1999 article from Science magazine.
- Scott Watson collected a number of Inflationary
Cosmology Links over the course of working on an undergraduate thesis
on that topic.
- Guth, Alan The Inflationary Universe Perseus Books,
Reading, MA, 1997. Popular science book at approximately Scientific
American level. Here Guth describes the nature of Inflation theory as
well as the history of its development.
See my Physics Links
Last modified: September 30th, 2001
Christopher B. Siren