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ZL2VAL > SETI 13.02.04 13:25l 87 Lines 4162 Bytes #999 (0) @ WW
BID : F10519ZL2VAL
Read: GUEST
Subj: Arecibo Diaries, Darwins Birth
Path: DB0FHN<DB0FOR<DB0SIF<DB0EA<DB0RES<ON0AR<WB0TAX<SP7MGD<VK3TE<ZL2BAU<
ZL2AQY<ZL2AB
Sent: 040213/1048Z @:ZL2AB.#46.NZL.OC #:35744 [New Plymouth] FBB7.00g
From: ZL2VAL@ZL2AB.#46.NZL.OC
To : SETI@WW
Darwin's Universe
By Peter Backus
Observing Programs Manager
posted: 07:00 am ET
12 February 2004
For most of history, people thought the sky was unchanging and life was
as it had always been. Many believed the Earth was the center of the
universe and that humans were in some way "higher" than all other
creatures. Then along came the Copernican revolution four centuries ago,
and suddenly Earth shifted out of the center of the universe to take up
its true position among the planets in our solar system. About two and a
half centuries later, another revolution took place when Charles Darwin
revealed the true relation between humans and all other life on Earth.
These revolutions are similar for the way they shift perspective, and
better inform us about our origins and our future.
We now know that everything changes. In four and a half billion years
the Earth changed from a hot, dry, cratered rock to a temperate,
ocean-dominated world teeming with life. We also know that most of the
life that ever existed on Earth has gone extinct. The way that life
changes, new species arising while others disappear, only makes sense
thanks to Darwin and his theory of evolution. A perspective on how
things change over time is also useful in astronomy.
When we look beyond the Earth, into deep space, we look back in history
and we see that the universe and its contents change with time. The
universe of 13.7 billion years ago has no stars, no planets, and no life
of any kind. The universe was very simple then, composed only of
hydrogen and helium. Slowly, clouds of these two gasses collapsed to
form stars and the universe began to evolve. Stars, you see, are
thermonuclear factories forming larger atoms from smaller ones.
Primarily, hydrogen converts into helium, in the process releasing
energy, which keeps the star from collapsing under its own gravity.
Heavier stars can form larger atoms like carbon, nitrogen, and oxygen.
Eventually, a star runs out of material for its nuclear furnace and it
"dies". In that process, the star ejects, sometimes in a spectacular
explosion, a fraction of its mass into space. The matter released by the
star at death differs from the material forming the star at its birth.
The ejected material is rich in heavier elements.
As new generations of stars form from the "evolved" remains of the old,
the content of the universe begins to change. Rocky planets form. Simple
molecules like water form and collect on the surfaces of these planets.
The Earth formed after eight billion years, and the deaths of countless
stars. On our young rocky planet, some interesting chemistry began.
Scientists debate among themselves about the origins of life on the
Earth. The exact mechanism and the location of Earth's "cradle of life"
remain for now shrouded in mystery. We do know, however, that the
process began with the birth of the universe itself and passed through
fusion fire in the hearts of giant stars.
As Carl Sagan said, we are made of "star stuff". We are one result of a
process of Cosmic Evolution. There is nothing particularly exceptional
about the Earth. The physical and chemical processes that happened here
can happen anywhere in the universe. Our modern understanding of the
processes driving astronomical and biological evolution gives SETI
astronomers great optimism. If intelligence evolved here, it can evolve
elsewhere, and we have the technology to find it if our analogues are
exploiting the electromagnetic spectrum to communicate as we do.
Spending the 195th anniversary of Darwin's birth on the grounds of the
Arecibo Observatory, I find myself contemplating such things as spider
webs, nebulae and the process of contemplation itself. From all of us
who carry human voyages of exploration into the cosmos, Happy Birthday,
Charles!
=========================
73 de Alan, (Sysop ZL2AB).
AX25:ZL2VAL@ZL2AB.#46.NZL.OC
APRS:!3903.34S/17406.45E]
IP :zl2val@qsl.net
Message timed: 23:39 on 2004-Feb-13 (NZT)
Message sent using WinPack-AGW V6.80
Points to ponder
~~~~~~~~~~~~~~~~
Don't cry because it's over; smile because it happened.
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