The Seven Wonders of the Universe


William Keel:

1. The Primeval Fireball, the Urknall - by whatever name, the defining event of
the observable Universe must rank, whatever your metaphysical disposition, 
and the wonder that all the others on the list depend on. And to this day
(2/3 or so of our current Hubble times later), everybody can still detect it
without even worrying about where to point their detectors.

2. The fantastic quintuple-imaged gravitational lens in the rich cluster
0024+1654. While there are plenty of gravitationally lensed objects from
our vantage point, the ring shape of the lensed galaxy and its five clear
yet distorted images seen around the cluster put this in a class by itself
for showing how mass affects the geometry of space-time.

3. The Great Wall of galaxies and clusters. A real superlative in both size and
mass.

4. The active galaxy Markarian 231. Its chaotic host galaxy betrays a past
merger, not falling anywhere along the Hubble sequence of galaxy types.
It's full of young stars around the nucleus, the core is driving an
immense wind outwards across tens of thousands of light-years, and 
the immense far-infrared power of its active nucleus (probably sneaking
a supermassive black hole into the list) makes it perhaps the most
luminous object in our corner of the Universe.

5. 30 Doradus and the Tarantula Nebula. The brightest star-forming region
in the Local Group (well, it can at least make a photo finish against NGC 604
in M33). The nearest really massive young star cluster, surrounded by a
brilliant array of hot young stars and ionizing a cloud of interstellar gas so
bright that it's still a naked-eye object from 150,000 light-years away.
At least for those of us for whom a few thousand miles of rock don't
spoil the view.

6. The Crab Nebula. For a while, astronomers were fond of saying that 
astrophysics consisted of studies of the Crab, and of everything else, in
equal proportions. A central pulsar flashing 30 times a second all the way
from radio waves to gamma rays; plasma waves flashing at huge speeds
outwards through the surrounding gas; and the billowing remnant of the
supernova explosion.

7. And, of course, the Earth. Even with the discovery of Jovian planets around
other stars, possible Martian microfossils, and the Arctic ice cap replayed on
Europa, our atmosphere and surface testify to the subtle intricacies and
power of thermodynamics displayed in the phase changes of water, and to the
host of condiions that have made this possible for such a long time. Whether 
you credit the Anthropic Principle or the Argument from Design, it remains the
jewel of the Universe. To borrow from the billboard of a popular barbecue
establishment, "Ain't nothin' like it nowhere".


T. Joseph Lazio:

2.  Gamma ray bursters - we don't know what they are or where they
    are.  That's the attraction.  The Universe can continue to
    surprise, astonish, and awe us.

3.  Cyg A - the strongest radio source in the constellation Cygnus,
    indeed in the entire sky.  High resolution observations show
    intricate filamentary structure in its radio lobes and jets that
    can be traced to a central engine.  Even higher resolution
    observations show that the central engine is less than 15 light
    years in size.

4.  Beta Pic, the Orion Nebula, and 51 Peg - the first clues that
    planets might be abundant in the Universe and we might not be
    alone

5.  Eta Carinae - a massive star undergoing its death throes 


Martin Hardcastle:

4. Cartwheel Galaxy