EAS BUSINESS…
September Meeting Recap
The speaker was John Armstrong from UW, speaking on the evidence and
alternative interpretations of it, for water on Mars.
Next Meeting – Saturday October 28th At
Providence Pacific Clinic Hospital – Monte Cristo Room – 7:00 PM
The
Everett Astronomical Society's next meeting will be Saturday October 28th, at
7:00 PM, in the PROVIDENCE Monte Cristo Room at Providence Hospital
PACIFIC Clinic at 916 Pacific Avenue in Everett. The speaker will be Vandana Desai of UW, with the topic "Galaxy Evolution in Clusters"
Scheduled Meeting Topics:
Nov 18 –
Brad Snowder, WWU, Native American star lore
Dec 16 –
Holiday party – Alfy’s on Broadway in Everett.
Member News
This is the
month for nominations for the club officers.
Please come to the meeting prepared to volunteer or to nominate someone
to be an officer for next year, so that we can keep activities going in the
club another year. Being an officer is
not an overwhelming job -- it provides a chance to contribute something to the
promotion of amateur astronomy in our area, and helps you meet new people and
try some fun new activities.
Officers
and duties: President (arrange speakers and meetings and conduct them), Vice-President
(stand in for President when necessary, and administer club telescopes,
schedule star parties), Treasurer (manage club finances and newsletter
mailing), and Librarian (keep and loan club materials).
Here are
some possible new club positions, to allow more people to participate in a
specific area of interest and minimize any overload on the existing
officers: Publicity-Promotions
(promote membership, advertise meetings and events), Star Party Organizer (set
up Sidewalk astronomy, club support of local star parties), Refreshments
(arrange for coffee, cookies, etc. at meetings), Programs (arrange
speakers and meeting programs), Newsletter (edit or assist with
newsletter and web page), Webmaster (set up and administer club web
page), and Astronomy Day Organizer (plan activities for Astronomy Day).
Financial Health
The club maintains a safe $1150+ balance. We try to
keep approximately a $500 balance to allow for contingencies.
Club Star Party Info
Dates for
this season’s club star parties:
We have come to the end of the season for regularly
scheduled star parties this year. We
plan to schedule monthly star parties again beginning in March next spring.
We try to hold
informal close-in star parties each month during the spring and summer months
on a weekend near the New moon at a member’s property or a local park. (call
Dave Mullen at (425) 347-3151 or club officers for info.) During the winter, phone tree is used to
arrange spur-of-the–moment events during clear weather spells when there are
significant celestial happenings.
Club Scopes’ Status
Scope Loan
Status Waiting
10-inch
Dobsonian On loan No wait list
8-inch Dobsonian On
Loan No wait
list
60 mm Refractor Available No wait list
Astro Calendar
October 2000
Oct
06 - Mercury Greatest Eastern Elongation (25 Degrees)
Oct 07 - EAS Star Party –
Schonberg’s house
Oct 21 - Orionids
Meteor Shower Peak
Oct 29-30 - Symposium
to Celebrate 100 Years of the Quantum: From Max Planck to Entanglement, Tacoma
Oct 28 - EAS Meeting 7:00 PM
– Providence Pacific Clinic
Oct
29 - Daylight Savings Ends - Set Clock Back 1 Hour
November 2000
Nov 03 - Taurids
Meteor Shower Peak
Nov 05 - Mercury At
Perihelion
Nov 05 - Jupiter
Occults HIP 20994 (9.8 Magnitude Star)
Nov 15 - Mercury At
Its Greatest Western Elongation (19 Deg.)
Nov 17 - Leonids
Meteor Shower Peak
Nov 18 - EAS Meeting 7:00 PM
– Providence Pacific Clinic
Nov 19 - Saturn At
Opposition
Nov 23 - Thanksgiving
Holiday
Nov 25 - Venus
Occults 187691 (7.9 Magnitude Star)
Nov 27 - Mars Occults
139039 (7.2 Magnitude Star)
Nov 28 - Jupiter At
Opposition
Asteroid Observing
(Especially if you have a camera or CCD camera…)
Oct 20 - 192 Nausikaa
At Opposition (8.6 Magnitude)
Oct 21 - 28 Bellona
At Opposition (11.0 Magnitude)
Oct 21 - 1470 Carla
Occults HIP 4778 (7.6 Mag Star)
Oct 22 - 192 Nausikaa
Occults TYC 1211 00680 (10.1 Mag Star)
Oct 24 - 3 Juno
Occults GSC 5782 00114 (11.3 Mag Star)
Oct 25 - 30 Urania At
Opposition (9.5 Magnitude)
Oct 25 - 230
Athamantis At Opposition (9.9 Magnitude)
Oct 25 - 261 Prymno
Occults TAC +09 00484 (11.2 Mag Star)
Oct 28 - 173 Ino At
Opposition (10.6 Magnitude)
Oct 29 - 12 Victoria
At Opposition (9.7 Magnitude)
Oct 30 - 372 Palma At
Opposition (10.9 Magnitude)
Nov 08 - Asteroid 324
Bamberga At Opposition (8.8 Mag.)
Nov 17 - Asteroid 31
Euphrosyne At Opposition (10.3 Mag.)
Nov 20 - Asteroid 115
Thyra At Opposition (9.6 Magnitude)
Over The Airwaves
E.A.S.
members, Jim Ehrmin, Pat Lewis, Greg Donohue and SAS member Ted Vosk present
the astronomy radio show, "It's Over Your Head", on radio station
KSER. The show is broadcast every
Wednesday morning at 7:20 AM to KSER FM 90.7.
The six minute astronomy segment gives a weekly look of what's up in the
night sky over Snohomish County. Pat would appreciate your suggestions about
subjects for scripts that you would find interesting. If you have information on a good subject, send her a copy. If you think of a good subject but don't
have the information, call her; she may be able to research it. Send to Pat Lewis, 5307 30th N.E., Seattle
WA 98105, or call (206) 524-2006.
If you are a listener of the program show your support by giving the
program director of KSER a call! KPLU
88.5 FM National Public Radio has daily broadcasts of "Star Date" by
the McDonald Observatory of the University of Texas at Austin, Monday through
Friday at 8:58 A.M. and 5:58 P.M. Saturday and Sunday). The short 2 minute radio show deals with
current topics of interest in astronomy.
The
University of Washington TV broadcasts programs from NASA at 12:00 AM Monday
through Friday, 12:30 AM Saturday, and 1:30 AM Sunday on the Channel 27 cable
station.
EAS Library – Book & Video List
The EAS has a library of books, videotapes, and software
for members to borrow. We always value
any items you would like to donate to this library. You can contact Mike Eytcheson to borrow or donate any materials.
MEMBERSHIP BENEFITS & INFORMATION
Membership in the Everett Astronomical Society (EAS) will
give you access to all the material in the lending library. The library, which
is maintained by Mike Eytcheson, consists of several VCR tapes, over 40 books,
magazines, and software titles.
Membership includes invitations to all of the club meetings and star
parties, plus the monthly newsletter, The Stargazer. In addition you will be able subscribe to Sky
and Telescope for $29.95 that
is $7 off the normal subscription rate, contact the treasurer for more
information. When renewing your subscription to Sky
& Telescope you should send your S&T renewal form along with a
check made out to Everett Astronomical Society to the EAS address. The EAS treasurer will renew your Sky and Telescope subscription for
you. Astronomy magazine ($29) offers a similar opportunity to club
members once a year in September.
EAS is a member of the Astronomical League and you will
receive the Astronomical League's newsletter, The Reflector. Being a member also allows you the use of
the club's telescopes, an award winning 10 inch Dobsonian mount reflector,
built as a club project or the 60mm refractor.
Contact Dave Mullen (425-347-3151) to borrow a telescope. EAS dues are $25. Send your annual dues to
the Everett Astronomical Society,
P.O. Box 12746, Everett, WA 98206.
Funds obtained from membership dues allows the Society to publish the
newsletter, pay Astronomical League dues and maintain our library.
OBSERVER’S INFORMATION…
Lunar Facts
Oct 05 First
Quarter
Oct 13 Full
Moon
Oct 20 Last
Quarter Moon
Oct 27 New
Moon
Nov 04 First
Quarter Moon
Nov 11 Full
Moon
Nov 18 Last
Quarter Moon
Nov 25 New
Moon
Up In The Sky -- The Planets
MERCURY is hidden in the glare of the Sun for now. It will reach greatest western elongation on
November 19th.
VENUS is low in the southwest in evening twilight. It will rise
higher over the next few weeks.
MARS (magnitude +1.8, between Leo and Virgo) glows orange in the
east-southeast at first dawn, far below the Sickle of Leo.
JUPITER is a very bright magnitude -2.7, and rises in the east
after sunset, to be above the horizon crud by about 10 PM. It is at opposition at the end of November
SATURN (magnitude -0.2,) rises a little ahead of Jupiter shortly
after dark. Saturn is to its upper right of Jupiter in Taurus, between the Pleiades cluster, and Aldebaran. It will reach opposition November 19th.
URANUS is magnitude 5.8 in
Capricornus
NEPTUNE (magnitude 7.9) is in Capricornus in the south after dark.
PLUTO is lost in the sunset.
Constellation(s) of the Month
TRIANGULUM: (The
Triangle). With a midnight culmination
date of October 23rd, Triangulum is well-placed for Fall
viewing. Triangulum borders on the
constellations of Andromeda, Aries, Perseus, and Pisces; there are no
established asterisms within its borders.
Triangulum ranks 27th in overall brightness among the
constellations, but 78th in size: it takes up approximately 131.85
square degrees (0.320%) of the sky.
Triangulum contains no known meteor showers, but one Messier object:
M-33 (also known as the Northern Pinwheel Galaxy). Triangulum is completely visible from latitudes North of –53
degrees, and completely invisible from latitudes South of –65 degrees. It has 12 stars brighter than magnitude 5.5,
and its central point is at RA=2h08m, Dec.= +31 degrees. The solar conjunction date of Triangulum is
April 24th.
M-33 is a
large, face-on spiral galaxy in Triangulum, and is, at a distance of 1.1
megaparsecs, the closest directly face-on spiral galaxy to Earth observers, but
is notorious for being difficult to find in backyard telescopes. Its total magnitude is 5.7, but on viewing
nights with sub-optimal seeing, backyard scopes will barely even show its
nucleus, let alone any spiral structure.
The reason for this is that M-33 is a very large, diffuse galaxy, with
dimensions of 62 x 39 arc minutes. When
this is combined with its direct face-on orientation, the spiral arms of the
galaxy offer a surface brightness of only 14.0 magnitudes per square
arc-minute. Larger apertures, good
seeing and dark skies, and low f/ratios show knotty patches of darker
nebulosity, faintly glowing spiral arms containing scattered brighter patches,
a small stellar-like nucleus, and NGC-206, a bright starcloud lying 10
arc-minutes northeast of M-33’s core.
In very, very dark skies with good seeing, M-33 is visible naked eye:
when this occurs, it overtakes the Andromeda Galaxy as the furthest object
visible without optical aid.
Triangulum
contains other galaxies as well: NGC-672 (an 11.6 magnitude barred spiral);
NGC-925 (a large but faint Sb-type spiral); and NGC 750-751, a small double
galaxy containing two elliptical galaxies: one 13th magnitude and
one 13.8 magnitude, separated by only 24 arc seconds. See if you can discover some of the beauties of Triangulum on a
clear, moonless night this Fall in the darkness away from city lights.
Young
Astronomer’s Corner
This column has addressed several topics in the past few years,
including monthly series on the life of a star (such as our sun), and
investigations of each of the planets, for example. This month, and at regular intervals in the future, the Young
Astronomer’s Column will engage in a question and answer column format,
answering some common and familiar questions heard frequently in astronomy
circles and science classrooms. So, we
hope we answer some of your questions in this manner. If not, let us know what your questions are (by calling an
Officer or the Newsletter Co-Editor for example), and we will do our best to
answer them!!!
Question: Is Saturn the only planet that has rings?
Answer:
No. All four
of the largest planets known as the “gas giants” (Jupiter, Saturn, Uranus, and Neptune) have rings. Those of Saturn are far and away the biggest
and brightest. Jupiter has one dark
ring which was discovered by the spacecraft known as Voyager 2. Neptune’s rings were also discovered by the
Voyager 2 fly-by. The rings of Uranus
were discovered as the planet was scheduled to pass in front of a star and the
star “blinked” even before the actual planet (the disk of Uranus) passed in
front of it (!); that is, there was something surrounding the planet that was
unknown at the time: nine darker, narrow rings!!
Question: What is the
“far side of the moon?”
Answer:
The side of the moon that never faces Earth. This is because the time it takes for the
Moon to rotate on its axis is the same time that it takes for the Moon to
rotate around the Earth. The only
photographs we have of the “far side of the moon” are those taken by man-made
satellites, including those containing the Apollo astronauts. The “far side” contains no large, smooth
dark areas (seas or “maria”) that we see on the “near side” from Earth, but
rather is mostly composed of craters.
Question: What is a “white dwarf?”
Answer:
A white dwarf is a “dying” star about the size of
planet Earth. When a star like the Sun
uses up all its hydrogen and helium as fuel, it remains very hot and bright for a long time, but shrinks to about
the size of the Earth. No new nuclear
reactions (which cause a star to give off heat and light) occur in a white
dwarf however, so it is often considered a “dead or dying” star. Because the star that forms a white dwarf
used to be much bigger, much of the matter that used to occupy a larger area is
compressed into a much smaller area.
This makes the star so dense that a teaspoon of the “star stuff” from a
white dwarf would weigh a couple of tons.
Eventually, white dwarfs cool even more, finally fading to black.
Astronomy and Telescope “Lingo”
Astronomy Lingo: SUPERGALACTIC PLANE: The dominant plane of the largest
concentration of nearby galaxy clusters in the sky, which passes through the
Virgo cluster of galaxies.
Telescope Lingo: GUIDE STAR CATALOG: Containing over 18 million celestial objects (mostly
stars), this Space Telescope Science Institute catalog serves as the database
for the very sensitive guidance system for the Hubble Space Telescope. It is available to the public on CD-ROM.
Astronomy Fun Facts
October Fun Facts:
** The Moon is 1 million times drier than the Gobi desert on
Earth. The only “floods” the Moon has
ever seen have been floods of molten hot lava spreading out over vast areas of
the lunar surface, creating the seas or “maria” that we see today.
** At some point in the evolution of the Universe, the
“weather” in “space” would have been warm, but livable. The Universe was approximately at human body
temperature (37 degrees Celsius or 98.6 degrees F.) when it was about 9.6 million
years old, and had a radius of ‘only’ approximately 154 million light years!
** The young Universe at about 4 minutes of age was as dense
as iron; at about 11 minutes, as dense as water, and at about 5 hours,
approximately as dense as air. Today,
many billions of years later, the Universe is “spread very thin”; indeed, were
it not for localized “clumpiness” which ultimately led to galaxy formation, we
would not be here to reflect on its density!!
“MIRROR” IMAGES
Because we live in the Northern Hemisphere, we often tend to
focus (in both observing and reading) on celestial objects in this
hemisphere. The point of this column is
to inform club members about similar objects in the Southern Hemisphere (to the
ones we are already familiar with in the Northern Hemisphere). The general
class of object will first be defined, and then a representative object from
each hemisphere will be described. Note: “MIRROR” IMAGES” is strictly the name
of the new column, and is not intended to imply that there is optical mirror
symmetry between the two objects.
“MIRROR”
IMAGES” is a bi-monthly column, and was last published in September. It will again be published in November, at
which time the topic will be:
classical novae.
Astronomical Notes --
On & Off the Net...
How
could something so small have so much debris lying around? That is the puzzle
presented by asteroid 433 Eros in the first major reports on the composition
and history of the 21-mile-long body, the solar system's first asteroid to be
subjected to close study.
Joseph
Veverka of Cornell University describes tiny Eros as having a surface
"saturated" with tiny craters smaller than 1 kilometer (0.6 miles) in
diameter and "abundant" with rocks 30 to 100 meters (33 to 109 yards)
across. The craters and the boulders, says Veverka, indicate many violent
collisions with the asteroid over time. But the gravity on Eros is so weak
"that intuition and calculation tell you that most of the debris
produced in a collision would have escaped -- but the surface is full of it."
Veverka explains: "We have several possibilities. One is that we simply
don't understand cratering events on small objects, and somehow the debris gets
thrown out at very low speeds. Or the ejected material ends up in the same
orbit as Eros, and over time the asteroid runs back into its own debris and
gathers it up, which is equally bizarre. We simply don't understand this."
Veverka,
professor of astronomy at Cornell, is the principal investigator on the
multi-spectral imager (MSI), or camera, and the NEAR infrared spectrometer
(NIS), two of the five instruments on board NASA's Near Earth Asteroid
Rendezvous spacecraft (known as NEAR Shoemaker), which has been in orbit around
Eros since Feb. 14. Between that date
and April 1, the four teams managing the instrument packages probed the
elongated asteroid for its mass distribution, elemental composition and
topography and elevation. Their four reports in Science form the most detailed
view yet of an asteroid. The Veverka team's report, "NEAR at Eros: Imaging
and Spectral Results," notes rock debris, "presumably blocks of
ejecta," scattered across the asteroid, but not uniformly. A strong
concentration of blocks, the report says, occurs in the complex depression west
of the saddle, a 10-kilometer (6-mile) depression. The distribution of blocks
shows a low density at high northern latitudes, but the rocks do not seem to
have collected in low-lying areas of the asteroid.
"What
is striking about Eros," says Veverka, "is that if I look at
the moon in great detail, I see lots of tiny craters and fewer blocks of rock.
But on this object, when I get down to sizes the size of a car, there are very
few craters and lots of boulders." And yet, he says, the surface of
Eros shows clear evidence of violent impacts.
The
astronomer concedes that little is known about collisions on small bodies with
low gravity -- "we have to extrapolate a lot," he says. But
calculations indicate that the gravity on Eros is so low that a ball thrown
from the surface would escape into space. "Most of the ejecta from a
violent collision would be traveling at a reasonable speed, and you would
expect it to escape. So we simply don't understand why the surface is littered
with so many blocks," says Veverka.
The
Veverka team also confirms previous reports that Eros -- an S-type asteroid,
the most common classification -- is a primitive relic of the emergence of the
solar system from a cloud of gas and dust.
"We
basically know that Eros is an example of a very primitive body in which
nothing much has happened other than formation and cratering. If you want the
most pristine material in the solar system that has had the least happen to it,
then Eros is a good example," Veverka says. The imaging team says there is no evidence that Eros has gone
through an Earth-like process of heating and segregation of metal from
silicates to form an iron core and rocky mantle. From an analysis of surface
elements -- by measuring radiation emissions -- and measurements of the gravity
field, it was determined that the asteroid is homogenous.
Eros,
the chunky asteroid named after the god of love, is slowly revealing to
scientists the mysteries of its size, rotation and other properties. Some of those findings, such as Eros' mass
and bulk density, appear in a paper by Dr. Don Yeomans of NASA's Jet Propulsion
Laboratory. Yeomans is the radio science team chief for NEAR-Shoemaker.
Scientists
have learned that Eros is most likely made of rocky material with a uniform
density throughout. The asteroid's bulk density is similar to that of Earth's
crust. Like Earth, the surface of Eros is covered with a layer of looser rock
and soil. Though it is about 6,700
trillion kilograms (14,700 trillion pounds) in mass, Eros is a fragment from
the breakup of a once larger asteroid. "It's a chip off a larger block
from millions of years ago," said Yeomans.
Eros
is rotating around its shortest axis, making one revolution every 5 hours and
16 minutes. As though thrown in a tight spiral pass by some cosmic quarterback,
Eros' rotation axis appears to remain steady on its journey through space.
Because the asteroid is so much smaller with much less gravity than Earth, it
wouldn't take an Olympic athlete to jump entirely off the surface into
space. Scientists were able to study
Eros' rotation, mass distribution and structure based on a series of
observations taken onboard the spacecraft. By photographing the asteroid and
measuring infrared light reflected from it, scientists could determine its
mass, detect minerals and record its motion. As the craft edged into closer and
closer orbits around the asteroid, it took fresh data that helped determine the
asteroid's size, shape and mass distribution. These activities were critical
for navigating the spacecraft in to tighter orbits about Eros so that close-up
images could be taken. "If we
didn't know the precise size, shape and mass distribution of the asteroid ahead
of time, it would not have been safe to send the spacecraft to within a few kilometers
of the asteroid's surface," said Yeomans. By the mission's end in February 2001, the total surface of the
asteroid will have been imaged and measured.
NASA's
NEAR Shoemaker spacecraft has spotted square-shaped craters on asteroid Eros, a
telltale sign of mysterious goings-on in the asteroid belt long ago. In the pantheon of cosmic geometry, curves
rule. Astronomy texts are filled with spiral galaxies, elliptical orbits, and
ring nebulae. There are no chapters on triangles or rectangles -- after all,
who ever heard of a square planet? Some of the simplest shapes, common in the
handiwork of humans, are just plain rare in space. Rare, but not impossible...
Last
month, astronomers were studying pictures of asteroid 433 Eros when they
noticed some unusual craters. Most impact craters are circular, but these were
square! An overzealous fan of Star
Trek might mistake the impact scars for places where cube-shaped Borg vessels
touched down and lifted off again, but scientists say they are natural --
albeit unusual -- features. "These square craters are not just
novelties, they tell us something very interesting," says Andy Cheng
of the Johns Hopkins University Applied Physics Laboratory. Cheng is the
project scientist for NASA's Near Earth Asteroid Rendezvous spacecraft, which
is orbiting Eros. "It's an indication that Eros is permeated with an
extensive system of fractures and faults. Typically on Earth when we find this
type of fractured area, the fractures form intersecting systems. Craters in
such a terrain look square; we call them jointed craters. The best example is
the Barringer Meteor Crater in Arizona."
Square
craters add to accumulating evidence that Eros is riddled with cracks and
ridges that extend the entire 33 km length of the peanut-shaped space rock.
"We first saw long grooves in global pictures of the asteroid when NEAR
was entering orbit around Eros in February 2000," continued Cheng.
"Now, if we look carefully, most of the close-up pictures seem to show
signs of grooves and ridges."
"We have to ask ourselves how these cracks could have formed.
Presumably they are the result of large impacts. The question is: did these
impacts take place after Eros was its present size and shape or while Eros was
part of a larger parent body?"
It's a question that goes to the heart of the asteroid's origin.
Scientists believe that billions of years ago, when the solar system was young
and planets were newly-forming, Eros circled the Sun in an orbit between Mars
and Jupiter. It was a denizen of the asteroid belt. Since then, collisions with
other asteroids and gravitational perturbations by Mars and Jupiter have
altered Eros's orbit, so that now it comes close enough to Earth to study with
spacecraft like NEAR.
We
know a great deal about Eros today, but what was it like at the dawn of the
solar system, before it became a "Near-Earth" asteroid? Was Eros once
part of a moon-sized planet between Mars and Jupiter, or has it always been an
isolated space rock? "If continued mapping confirms that faults and
ridges extend from one end of Eros to the other, I would consider it to be
strong evidence that Eros is a piece of something that was once much
larger," says Cheng. If all of the rocks in the modern-day asteroid
belt were assembled, they would form a small planet about 1500 km in diameter
-- roughly half the size of Earth's moon. Such a body might have existed in an
orbit between Mars and Jupiter billions of years ago, before it shattered as a
result of collisions with other planetoids.
But if Eros is a "chip off the old block," there's a new
mystery to consider. When rocky planets like the Earth and its moon (and maybe
the parent body of Eros) are formed, heavier elements sink to the core while
lighter ones remain near the crust. This leads to a core-mantle structure with
distinctive chemical signatures in each layer.
The
looming conundrum is that Eros does not exhibit the chemical signatures of
differentiation. NEAR X-ray spectrometer data show that aluminum, magnesium,
and silicon on Eros have the same relative abundances that they do in the Sun
and in the early solar nebula. Evidently, Eros was not part of a body that
experienced the Earth-like process of heating and segregation of metals from
silicates to form an iron core and rocky mantle. "Eros is an example of
a very primitive body ... nothing much has happened to it other than formation
and cratering. If you want the most pristine material in the solar system
[where very little has happened] Eros is a good example," says Joe Veverka,
professor of astronomy at Cornell University, and the principal investigator
for two of NEAR's cameras.
Can
Eros be both -- a primitive, undifferentiated body and a fragment from a
long-ago planetoid? It's a possible contradiction that puzzles researchers. "Even before we visited Eros we knew
that asteroids were a mixed group -- some appear to be differentiated and some
not," says Cheng. "The largest asteroid of all, 933 km-wide
Ceres, is not differentiated. Yet, we believe it's possible for objects even
smaller than Ceres to melt and chemically segregate. We simply don't know why
some asteroids appear to be more primitive than others. We have to reserve a
little skepticism here and pursue this mystery." Cheng says that a global map of Eros's
grooves and ridges -- and possibly more square craters -- will likely shed new
light on the asteroid's history. For now researchers and asteroid enthusiasts
wait with anticipation as NEAR Shoemaker continues its first-ever and often
surprising survey 433 Eros, knowing that the best answers and most perplexing
mysteries may be yet to come.
http://spacescience.com/headlines/y2000/ast26sep_1.htm
http://near.jhuapl.edu
ONE
WEEK in 1997, a mouse of a galaxy between the shoulders of Hercules turned into
a monster. "It was rather inconspicuous before," says Heinz
Vslk, who watched the action from the island of La Palma. "But all of a
sudden it became the strongest source we've ever seen." This outburst from the galaxy Markarian 501
has left scientists in a quandary. The most energetic photons in the blast had
trillions of times the energy of a visible photon, and according to the laws of
physics as we understand them, they should never have made the vast journey
from that galaxy to Earth. They should have been snuffed out by the sea of
infrared radiation that fills space.
So
what's going on? Some physicists think there's something weird happening inside
Markarian 501: bunches of photons are ganging up into exotic globs called
Bose-Einstein condensates. Others say there'll be an everyday explanation once
they've mulled over the facts and figures a little more. But some scientists
think that Markarian 501 is telling us something momentous. It might, they say,
go down in history as the key to a 21st-century revolution, a theory that at
last marries quantum mechanics with Einstein's theory of gravity. Then this
galaxy would be a gateway to a hidden realm of nature where space and time are
radically transformed.
Markarian
501 is no newcomer to astronomers. It appears on photos of the constellation
Hercules dating back at least a century, and gets its name from Beniamin
Markarian, a Georgian astronomer at the Byurakan Astrophysical Observatory in
Armenia who started to compile a catalogue of hundreds of bluish galaxies in
the 1960s. Numbers 501 and 421 in his
catalogue are special. At around 300 million light years away, they are the two
closest examples to Earth of a rare and strange type of astronomical object
known as a ‘blazar’. Like other kinds of active galaxy, such as quasars and
radio galaxies, blazars are thought to be powered by a central black hole which
feeds on the gas, dust and stars that whirl around it in a hot disc. Above and
below the hole, two jets of energetic protons and electrons shoot millions of
light years into space. Blazars are
capricious, flaring up and dimming again within just a few days. Astronomers
think that this is because of their orientation. We see an active galaxy as a
blazar if one of its jets is pointing towards us, as though we're looking down
the barrel of a gun. The jet sends out a narrow beam of radiation whose
brightness can change rapidly as it shifts slightly or its supply of material
from the black hole changes.
This
special alignment also means we are assailed with ferociously energetic
radiation. In 1992, the orbiting Compton Gamma Ray Observatory picked up
high-energy gamma rays from Markarian 421. Astrophysicists believe they are
cooked up in the jet by superfast particles. As electrons and protons spiral
around the jet's strong magnetic fields, they emit powerful radiation. They
could also be colliding with ordinary photons, boosting them to ultra-high
energies.
But
it wasn't until March 1997 that astronomers saw what a blazar can do when it
really flexes its muscles. They watched astonished as Markarian 501 flared up
from one of the puniest gamma-ray sources in the sky to upstage even the Crab
Nebula, the debris of an exploded star in our own galactic backyard, which is
the brightest steady gamma source in the sky. The outburst lasted several
months, and at its peak Markarian 501 was ten times as bright as the Crab, despite
being 50,000 times farther away. "The distance difference is just
mind-blowing," says Vslk, a director at the Max Planck Institute for
Nuclear Physics in Heidelberg. Vslk is
a spokesman for an experiment called HEGRA (High Energy Gamma Ray Astronomy),
which kept its eye on Markarian 501's storm from La Palma, in the Canary
Islands. When a high-energy gamma ray hits the upper atmosphere, it sparks an
"air shower" -- a spreading cascade of superfast subatomic particles.
These emit light, and because they move faster than the speed of light in air
their emissions pile up into blue flashes known as Cerenkov radiation -- just
as sound waves from supersonic aircraft pile up into a sonic boom.
During
501's outburst, HEGRA's six big mirrors saw astoundingly bright blue flashes.
These indicated that some of 501's gamma rays had energies of up to 22
tera-electronvolts. This is trillions
of times as much as a photon of visible light, which has an energy between 1
and 3 electron volts. What is hard to
explain is why the gamma rays made it to Earth. When a high-energy gamma ray
and an infrared photon collide, they have enough energy to mutate into an
electron and a positron. So the gamma rays should be gradually mopped up by the
sea of far-infrared photons that fills space, emitted by forming stars and hot
dust. How far the gamma rays get
depends on how many far-infrared photons are out there. In the past two years,
several teams of scientists have taken old images from NASA's Cosmic Background
Explorer (COBE) satellite and the European Space Agency's Infrared Space
Observatory (ISO) and used some novel mathematical tricks to cancel out the
infrared from our own Solar System and Galaxy. The results show that the
far-infrared background is so bright that gamma rays with energies of more than
10 tera-electronvolts should never reach the Earth from as far away as
Markarian 501. So why did we see them?
Perhaps the gamma rays are colluding against us, says Peter Biermann, an
astrophysicist at the Max Planck Institute for Radio Astronomy in Bonn. He and
his colleagues suggest that several gamma rays from Markarian 501 might merge
into a Bose-Einstein condensate -- a densely packed globule of lower-energy
photons that have exactly the same positions.
This
should happen to light from a super-efficient laser -- one far more efficient
than any yet built on Earth. Nature does build lasers: in many active galaxies,
X-rays make clouds of water vapor emit microwave laser light. The Universe is
dotted with billions of these microwave lasers, or "masers". But is a
natural, super-efficient, ultra-high energy laser plausible? Biermann claims
that it could conceivably happen when a group of excited atoms in a blazar's
jet all stimulate each other to emit light at the same.
Say
the blazar fired out a Bose-Einstein condensate of 20 identical gamma rays with
energies of 1 tera-electronvolt each. Because these photons have relatively low
energy, they would be unimpeded by the far-infrared background. Arriving
together in the Earth's atmosphere, they would dump 20 tera-electronvolts of
energy at the same point in the atmosphere, just like a single
20-tera-electronvolt gamma ray.
Scientists
are now taking another look at HEGRA's observations to test this idea. They're
looking for a subtle difference between the air showers a high-energy photon
would trigger in the atmosphere and those produced by a ball of less energetic
ones. Though they both have the same total energy, a lone high-energy photon
would create a narrower, more chaotic air shower. "It's like if you
have a very heavy truck in a accident in the highway -- there's an
incredible scatter." says Biermann. "But 20 teeny trucks might
do next to nothing."
Natural
gamma-ray lasers may sound like an outlandish explanation, but another
possibility would be far more momentous. Giovanni Amelino-Camelia, a physicist
at the University of Rome, believes that Markarian 501's gamma rays might be
subject to an entirely new kind of physics that rules the high-energy world.
For decades, physicists have been trying to marry quantum theory with general
relativity, Einstein's theory of gravity. Most of their fledgling theories of
quantum gravity predict that on tiny scales, approaching 10**-35 meters, our
picture of smooth space and time falls apart, giving way to a seething froth of
quantum gravity fluctuations dubbed space-time foam.
If
so, odd things start to happen. As photon energies get higher, the speed of
light might start to drop off by a tiny amount, because the very short
wavelength would mean that the light started to "feel" the bumpiness
of space-time. "A very rough analogy is that if you roll a soccer ball
across a table with lots of tiny ridges, it will travel at roughly the same
speed it would have done if there were no ridges," says Amelino-Camelia.
"But if you roll a tiny little ball, its path will be strongly altered
by all the little valleys in the table."
Feeling
the bumps in space would not only slow very high-energy photons, it would help
them avoid infrared photons. Raymond Protheroe of the University of Adelaide in
South Australia and Hinrich Meyer of Wuppertal University in Germany calculate
that provided quantum gravity does indeed kick in at a scale of 10**-35 meters,
this could give 20-tera-electronvolt photons just the edge they need to ignore
the far-infrared background and make it from Markarian 501 to Earth.
What's
most compelling, Amelino-Camelia says, is that this could also explain another
cosmic conundrum. Protons with giant energies of more than 10**20 electron volts
are occasionally detected hitting our atmosphere. For years, astrophysicists
have wondered why. The only known sources that could produce such energy are
distant active galaxies, which means that these protons should also be eaten up
by background radiation -- this time the relic microwave radiation of the big.
According
to calculations announced last month by Amelino-Camelia and Tsvi Piran of the
Hebrew University in Jerusalem, the same roughness of space-time needed to
explain the gamma rays from Markarian 501 also solves the cosmic ray problem.
"The remarkable point is that you have these two problems at very
different energy scales and contexts," says Amelino-Camelia. "Yet
with the same equations, we can explain both." Amelino-Camelia admits there's a lot of
guesswork going on. But for the first time, he says, nature might be throwing
us some solid clues to quantum gravity. "And even if the correct
explanation is different, we are finally obtaining data that are relevant to
our understanding of the small-scale structure of space-time," says
Amelino-Camelia. "This really is a turning point."
To
find out if space-time is truly fuzzy in this way, Amelino-Camelia thinks
astronomers should look to gamma-ray bursts. These are bright bursts of gamma
rays that appear unpredictably anywhere in the sky and come from distant,
mysterious sources. If astronomers could catch a very distant and bright burst,
the highest-energy photons may lag slightly. He says present-day detectors
aren't sharp enough to pick up the tiny timing differences necessary. "But
on the space station and other orbiting observatories, we'll acquire this level
of sophistication over the next few years."
If
Amelino-Camelia's speculations hold true, they could lead to a change in our
concept of time as radical as that brought about by relativity at the beginning
of the 20th century. "Special relativity said that time is not
absolute. That was the breakthrough for mankind at that time," he
says. Quantum gravity implies that time
comes in discrete pieces. What's more, like Schrsdinger's proverbial cat, which
is neither dead nor alive until we choose to look at it, time would exist as a
jumble of different possible values. "The concept of 'now' becomes just
a rough approximation," says Amelino-Camelia. Not everyone agrees that Markarian 501's
message is this radical. "That's a rather outré possibility,"
says Sheldon Glashow of Boston University. He believes that other experiments
have made such large departures from smooth space-time look extremely unlikely,
and thinks there's probably a simpler answer to the puzzle -- perhaps that
we've overestimated the distance to the blazar. If it is closer than we think,
energetic gamma rays could make the journey to Earth despite the infrared
background.
Erasing
the Milky Way
Biermann
agrees that something mundane could turn out to be the key. "My gut
feeling is that the solution is something simple that we're just not seeing,"
he says. Along with Vslk, he'd put his money on the latest far-infrared
measurements being wrong. "The measurement of the far-infrared
background is notoriously difficult," says Biermann. He thinks that
improved tricks for erasing the Milky Way from COBE and ISO images to work out
the strength of the far-infrared background might show it to be weaker than we
now think. One way to resolve this
would be to look at more distant blazars. A whole new generation of gamma-ray
telescopes is due to get under way. Scientists from Germany, France and Italy
are building a telescope array in Namibia called HESS (High Energy Stereoscopic
System). The array, with up to 16 telescopes, will be 10 times as sensitive as
HEGRA, and could pick up blazars 30 times as distant as Markarian 501. The first four HESS telescopes should start
operating next year, along with a German telescope called MAGIC (Major
Atmospheric Gamma Imaging Cerenkov Telescope). MAGIC, at the HEGRA site on La
Palma, will gather Cerenkov light using a mirror 17 meters across. Further down
the line, there are plans for an American telescope called VERITAS (Very
Energetic Radiation Imaging Telescope Array System). Sited at the foot of Mount
Hopkins in Arizona, this array will have seven mirrors, each 10.4 meters
across, and start operating sometime in 2004 or later.
If
the new telescopes find that Markarian 501's even more distant cousins are
relentlessly pelting us with 20-tera-electronvolt gamma rays, ordinary physics
will be hard pushed to explain why. "This would deepen the suspicion
that something dramatically new is happening," says Meyer. Whatever
happens, the performance of the Universe's most histrionic galaxies will be
under the spotlight for years to come.
- Hazel Muir, New Scientist, 23rd September 2000
http://www.newscientist.com
Giant
fountains of fast-moving, multimillion-degree gas in the outermost atmosphere of the Sun have revealed an
important clue to a long-standing
mystery -- the location of the heating
mechanism that makes the corona 1,000 times hotter than the Sun's visible surface. Scientists discovered an important clue while observing
immense coils of hot, electrified gas,
known as coronal loops. These fiery,
arching fountains now appear in unprecedented detail with NASA's Transition Region and Coronal
Explorer (TRACE) spacecraft.
Scientists
are interested in the corona, which appears as a halo of light seen by the unaided eye during a total solar
eclipse, because eruptive events in
this region can disrupt high-technology
systems on Earth. Astronomers also hope to use the solar corona studies to better understand other
stars. "The mysterious energy
source that makes the Sun's atmosphere so
incredibly hot has been an enigma for more than 70 years, and before we discover what it is, we needed to
learn where it is," said Dr.
Markus Aschwanden of the Lockheed-Martin Solar and Astrophysics Laboratory (LMSAL), in Palo Alto, CA. "Locating the source of coronal heating is a key piece of this
puzzle, and we are excited that solar
observatories like TRACE are allowing us to resolve the hidden events occurring in the atmospheres
of stars."
The
new observations reveal the location of the unidentified energy source, showing that most of the
heating occurs low in the corona,
within about 10,000 miles from the Sun's visible surface. The gas fountains form arches, hundreds of
thousands of miles high, capable of
surrounding 30 Earths. As gas emerges from the
solar surface, it's heated and rises, then cools and crashes back to the surface at more than 60 miles per
second. Millions of different-sized
coronal loops comprise the corona, and
a 30-year-old theory assumes the loops are heated evenly throughout their height. The TRACE
observations show that instead, most of
the heating must occur at the base of the loops, near where they emerge from and return to the solar surface. The old theory of uniform heating predicted
that the loops would be substantially
hotter at their tops because gas at the top of
the loops is thinner, and does not radiate heat away as efficiently as the dense gas near the
bottom. If the loop were heated evenly
over its entire height, the top, which can't lose heat as well, would become hotter than the rest. Earlier, less-
detailed observations of the coronal loops could not confirm nor invalidate the uniform heating theory
because they could not reveal that the
loop tops were really about the same temperature as the bases. However,
the high-resolution TRACE pictures show that, just as a thick piece of rope consists of many thin
fibers, what was thought to be one
coronal loop is actually a bundle of thin, individual loops. Although some thin loops in the bundle are hotter
than other spirals, precise
measurements by TRACE show that, over its
height, each separate, thin loop varies much less than the uniform heating theory predicts. "Since a loop loses heat most
rapidly from its bases, most of the
heat must also be going in at the bases for the loop to be at a uniform temperature," said Dr.
Karel Schrijver, a member of the
research team, also of LMSAL. "If this were not so, the
lower parts would have been much cooler
than the tops, which do not lose heat
as quickly."
TRACE,
launched in April 1998, is training its powerful telescope on the "transition region" of the
Sun's atmosphere, a dynamic region
between the relatively cool surface and lower atmosphere regions of the Sun, about 10,000 degrees
Fahrenheit, and the extremely hot upper
atmosphere, which burns up to 3 million
degrees Fahrenheit.
For
images and more information on the Internet, visit: http://www.gsfc.nasa.gov/GSFC/SpaceSci/sunearth/tracecl.htm
Researchers
using the testbed interferometer at Palomar Observatory have achieved the
best-ever distance measurement to a type of star known as a Cepheid variable.
The new results improve the "cosmic yardstick" used to infer the size
and age of the universe. A group of
astronomers from Caltech, JPL, and the Infrared Processing and Analysis Center
announced that the distance to the star Zeta Geminorum in the Gemini
constellation is 1,100 light years. The degree of accuracy in the measurement
is about 13 percent, meaning that the star could be as close as 960 or as far
away as 1,240 light-years. This
represents an improvement of a factor of three over previous measurements. The improvement is due to the use of the
Palomar Testbed Interferometer, of which JPL engineer Mark Colavita is the
principal investigator and codesigner.
"This
has been a bit of a Holy Grail in the field," says Benjamin Lane, a
graduate student in Caltech's planetary science program and the lead author of
the study. "The measurement of accurate distances to Cepheids is widely
considered to be a principal limitation in determining the Hubble constant."
Cepheid
variables for several decades have been an important link in the chain of
measurements that allow astronomers to estimate the distances to the farthest
objects in the universe -- and ultimately, the overall size and expansion rate
of the universe itself. Cepheid
variables are stars that have very predictable relationships between their
absolute brightness and the frequency with which they brighten up. A Cepheid is
useful for measuring distances because, if it is known how bright the star
really is, then it is a simple task to measure how bright it appears on Earth
and then calculate the distance. A good
analogy is a light bulb shining at an unknown distance. If we are certain that
only 100-watt light bulbs brighten once a day, and we observe that the light
indeed brightens once daily, then we can calculate its distance by measuring
the brightness of the light reaching us and comparing it to the known absolute
brightness of a 100-watt light bulb.
"Zeta
Geminorum is known to grow larger and smaller," says Lane. "We
already knew this because we can see the Doppler effect." In other
words, astronomers can measure a slight difference in light coming from the
star because the surface of the star moves toward us and away from us as the
star expands and contracts.
In
the study, the researchers couple this information with new data collected with
the Palomar Testbed Interferometer. The interferometer combines the images from
two 16-inch telescope mirrors in such a way that images are as sharp as they
would be if the telescope mirror were 360 feet in diameter. Data from the interferometer showed that
Zeta Geminorum went through a change in angular size of about five
hundred-millionths of a degree during its 10-day cycle. "That's roughly the size of a
basketball on the moon, as seen from Earth," says Colavita.
From
previous Doppler measurements, the researchers already knew that the change in
the star's diameter was about 4.2 million kilometers. By combining that
information with the newly measured change in angular size, they were able to
deduce the distance to the Cepheid.
The direct measurement of distance to Zeta Geminorum shows that the
basic technique works, Lane says. "As a graduate student, it has been
exciting to be at the leading edge of this field."
The
Palomar Testbed Interferometer was designed and built by a team of researchers
from the JPL in Pasadena, led by Colavita and Michael Shao. The interferometer
is located at the Palomar Observatory near the historic 200-inch Hale
Telescope. The device is intended as an engineering testbed for the
interferometer that will soon link the 10-meter Keck Telescopes atop Mauna Kea
in Hawaii. The Keck Interferometer has
been funded to find and study extrasolar planets. The Navy and the NSF are also
funding the development of interferometers for astrometry and stellar
astronomy.
"The
current precision is a significant improvement over the previous
determinations, but we expect to achieve distance measurements at the level of
a few percent in the near future," says Shri Kulkarni, a professor of
astronomy and planetary science at Caltech.
Spanish
and German astronomers report their discovery of isolated giant planets
undergoing formation. Researchers
coordinated by Professor Rafael Rebolo (IAC/CSIC), have discovered in the Orion
region three giant planets and another fifteen bodies, whose planet status
could be confirmed once analyses are completed. The planets detected are reported to have masses between 5 and 15
times the mass of Jupiter, the largest planet in the Solar System. The results include unprecedented images and
spectra of bodies whose planetary masses are not associated to a given
star. The super-Jupiters examined roam freely in Orion's Sigma cluster, a
very active star formation region located at approximately 1000 light years from
Earth. The age of these extraordinarily
young planets is expected to be less than five million years.
Images
of these solitary planets have been obtained in the visible range with the
2.5-m Isaac Newton Telescope, at La Palma, and in the infra-red, with the 3.5-m
telescope at Calar Alto Observatory (Almeria, Spain). The combination of these data has allowed identification of a
large concentration of very dim, exceedingly red objects, in a small region
surrounding Orion's stellar system known as Sigma Orionis. These features are characteristic of giant
planets currently undergoing a
formation process. Subsequently, the spectra obtained with the
world's largest telescope - the 10-m Keck telescope on Mauna Kea
Observatory confirmed these findings.
Although
the existence of Jupiter-like bodies orbiting stars has been known since 1995,
images of these giants have not been obtained to date, essentially because they
are as much as one thousand million times fainter than the stars they are orbiting. The
contraction process affecting these newly detected planets is in full swing -
which means that their size is diminishing due to gravity - and they irradiate
about ten thousand times more energy than is to be expected once they reach the
size of Jupiter, i.e. when they become more stable. To capitalize fully on this circumstance, researches began
exploring in 1998, surveying the Orion region, renowned for hosting huge
numbers of young stars, in the search for giant planets. The new results show, for the very first
time, images and spectra of bodies showing planetary masses which oddly enough
are not linked to any of the surrounding stars. These so-called super-Jupiters float freely within a star
cluster, but at distances sufficiently large to allow them to avoid the
gravitational attraction of other stars.
Of the eighteen candidates detected so far, three have been scrutinized
using spectroscopic techniques and have been confirmed as gaseous objects with
surface temperatures in the range 1,500 degrees Celsius, as expected for
planets slightly less massive than
Jupiter undergoing very early
evolutionary phases.
In
the words of Prof Rebolo, "this discovery is a challenge for current theories. In fact, a definitive explanation is still
lacking. These bodies appear to be far
too numerous and young to have formed in protoplanetary disks and later ejected
as a result of the collisions between stars present in the disks. A more plausible hypothesis is that they
emerged directly from the fragmentation and collapse of clouds of dust, a
process that may well occur in a few million
years time".
However, the fragmentation
scenario poses difficulties from the theoretical point of view when attempting
to explain the formation of bodies with masses so close to Jupiter's, and hence
a definitive explanation for their existence is still pending.
The objects detected in Orion will cool down
progressively - according to Víctor Sánchez Béjar, a PhD student and team
member at the IAC - and in a few hundred million years will reach surface
temperatures in the range 0 to 100 degrees centigrade. They will never develop rocky regions and
temperatures will continue to drop until they fall in the range of Jupiter's.
It
is still premature to affirm how many of these giant planets may be present in
the Galaxy. However, if the
statistics inferred for
Orion were representative of the
entire Milky Way, hundreds of millions of isolated super-Jupiters would be
found populating interstellar
space. According to the researchers involved in the study, there are indications that they
could be as numerous as solar-type
stars. In the Sun's neighborhood
(i.e. in a radius of 20 light years)
there could be 30 or 40 such objects.
Their discovery is clearly a challenge for current technologies.
3D
ANIMATED MOVIES - ftp://ftp.ll.iac.es/outlong/lcc
http://www.iac.es/gabinete/noticias/2000/oct051.htm
Astronomers
using the NSF's Very Long Baseline Array (VLBA) of radio telescopes have
discovered a cloud of gas apparently being struck by a jet of ultrafast
particles powered by the energy of a supermassive black hole at the core of a
galaxy 450 million light-years away. A
collision between the jet of subatomic particles and the gas cloud caused
flickering of radio waves at a particular location in the jet during a 16-month
series of VLBA observations.
"This
cloud, about 25 light-years away from the black hole, represents a 'missing
link' that will help us understand the complex regions around the central black
holes in active galaxies," said Jose-Luis Gomez, the team leader.
The
researchers produced a "movie" of changes in the galaxy's jet over
the 16-month observing period. "This
movie is the result of perhaps the most complete monitoring of such a jet ever
done," said Gomez. Active
galaxies come in a variety of types, including Seyfert galaxies, radio
galaxies, and quasars. All are believed
to harbor a giant black hole at the center.
Black holes are concentrations of matter so dense that, within a certain
distance, not even light can escape the gravitational pull. In active galaxies, material drawn toward
the black hole is thought to form a disk of material that tightly orbits the
black hole. Such an "accretion
disk" is believed responsible for generating jets of material that,
drawing on the black hole's gravitational energy, are boosted to speeds nearly
equal to that of light.
In
the past, astronomers have found evidence for dense clouds of gas near the
accretion disk that are presumed to be moving rapidly. Farther from the black hole, other, less
dense gas clouds show evidence of less-rapid motion. "We're not sure whether these clouds are moving away from
the black hole, toward it, or in some random manner," said Gomez. "The gas cloud we have found in
3C120 is isolated and intermediate in distance from the central black hole. With further study, we think we can
determine just which way it is moving, and thus help answer the question of
just how these gas clouds in the central regions of active galaxies are
behaving."
In
their study using the VLBA, the astronomers were able to track the motions of
concentrations, or "blobs" of material in the jets spewn out from the
core of 3C120. At a distance of about
25 light-years from the presumed location of the central black hole, they noted
that some of the blobs seemed to turn on and then off over the course of a few
months. They interpreted this as
evidence of a collision of the jet particles with the gas cloud. Other evidence showed that the shock of the
collision affected the magnetic field of the blob. They also saw evidence that the "nozzle" of the jet may
change its direction slightly, changing the place where the jet strikes the gas
cloud.
The
VLBA is a continent-wide radio-telescope system, with one telescope on Hawaii,
another on St. Croix in the Caribbean, and eight others in the continental
United States. Part of the National
Radio Astronomy Observatory, the VLBA offers the highest resolving power, or
ability to see fine detail, of any telescope available.
DON’T
FORGET !
Set
up your telescope in your yard and give folks a real “treat” on Halloween
night!
FROM THE EDITOR'S TERMINAL
The Stargazer is your newsletter
and therefore it should be a cooperative project. Ads, announcements, suggestions, and literary works should be
received by the editor before the 1st of the month of publication, for example,
material for May's newsletter should be received May 1st. If you wish to contribute an article or
suggestions to The Stargazer please contact Mark Folkerts by telephone (425)
486-9733 or by mail (18925 - 67th Ave SE, Snohomish, WA 98296), or
co-editor Bill O’Neil, at (425) 337-6873.
