Battle Point Astronomical Association

The BPAA Grand Old Fourth prize-winning parade entry overrun by aliens. Click here to see more of BPAA’s Fourth,

September

September 3: 7 p.m. BPAA Board Meeting
September 7: John Rudolph Memorial Planetarium Fund Kiwanis Brunch, Wing Point
September 7: First quarter Moon
September 12: 7 p.m. Members Meeting (subject to cancellation; check bpaa@yahoogrooups.com)
September 13: Uranus at Opposition
September 15: Full Moon
September 20: 7 p.m. Planetarium Show: “Wild Stars:Neutron Stars, Pulsars, Supernovae & Black Holes” and Star Party   
September 21: 5th Anniversary (2003) Galileo, Jupiter Impact
September 22: Autumnal Equinox 8:44 a.m. PDT; Last quarter Moon
September 29: New Moon

October

October 1: 7 p.m. BPAA Board Meeting; NASA’s 50th Birthday (1958)
October 5: John Rudolph Memorial Planetarium Fund Kiwanis Brunch, Wing Point
October 7: First quarter Moon
October 9: Draconids Meteor Shower Peak
October 10: 7 p.m. Members Meeting (subject to cancellation; check bpaa@yahoogroups.com)
October 11: 40th Anniversary (1968), Apollo 7 Launch (1st manned Apollo mission)
October 14: Full Moon
October 21: Orionids Meteor Shower Peak; Last quarter Moon
October 25: 6 p.m. Planetarium Show: “A Tour of the Galaxies” and Star Party
October 28: New Moon

November

November 2: John Rudolph Memorial Planetarium Fund Kiwanis Brunch, Wing Point Daylight-saving time ends
November 3: Taurids Meteor Shower Peak
November 5: 7 p.m. BPAA Board Meeting; First quarter Moon
November 10: Deadline for Winter issue of BPAA Newsletter
November 13: Full Moon
November 14: 7 p.m. Members Meeting (subject to cancellation; check bpaa@yahoogroups.com
November 17: Leonids Meteor Shower Peak
November 19: Last quarter Moon
November 22: 5 p.m. Planetarium Show: “Best of the Southern Hemisphere and Meteor Showers” and Star Party
November 27: New Moon

Diane Colvin, BPAA Events Manager

Summer fnally arrived and we got some long-awaited clear skies. Fall is coming soon, and we can only hope the good weather will persist. The autumn sky holds many rewards for the backyard sky gazer, along with the advantage of those extra evening hours of darkness. In September, perhaps the best bet for clear skies, Venus, Mercury and Mars are within 4 degrees of each other during the frst half of the month. On September 7, the moons Io and Ganymede will cast shadows on Jupiter. On September 19, Venus, Mercury, Mars and Spica will be bunched together low in the west-southwest.

Fall also brings the possibility of some worth-your-while meteor showers. On October 9, the Draconids peak. On October 21, check out the Orionids. The Orionids, along with the Eta Aquarids, occur each year as a result of Earth passing through dust released by Halley's Comet. The point from where the Orionid meteors appear to radiate is located within the constellation Orion. Max this year is predicted at 20 meteors per hour. On November 3, the Taurids peak. The Taurids are a very old meteor stream. On November 17, the Leonids are at their peak, but the moonlight will interfere. You can learn more about meteor showers at the November planetarium show.

False color representation of Jupiter’s Great Red Spot taken with Galileo’simaging system June 26, 1996. Courtesy The Jet Propulsion Laboratory, Pasadena, CA

September 21 is also worth noting. It's the fifth anniversary of the end of the Galileo spacecraft's 14-year odyssey. Talk about getting a bang for your buck. Galileo was truly an over-achiever. These days, when billions of federal dollars are wasted on mostly things destructive, and hardly anything productive, we should all wish for another Galileo. Galileo endured more than four times the cumulative dose of harmful radiation it was designed to withstand. It had an exciting list of discoveries even before it got a glimpse of Jupiter. Once it got to Jupiter, its data was extensive, both on the planet itself and its four largest moons.  

Please note that in September, October and November the planetarium shows and the beginner sessions for our local star parties will begin earlier each month, at 7:00 p.m., 6:00 p.m., and 5:00 p.m. respectively. And remember that any member at any time who is planning to observe can invite others to join in by sending an email to bpaa@yahoogroups.com. To join our email group, send an email with your name to bpaa-owner@yahoogroups.com and we can enroll you. If you want to also have web access to the messages and fles, you can join the Yahoogroups by clicking the register link for new users on http://groups.yahoo.com/ , and requesting to join our group at http://groups.yahoo.com/group/bpaa/ . The system will send us a message, and we'll approve your request after we verify your membership.

Harry Colvin

It is nice for a change to not complain about the weather or lack of clear skies for viewing. After a terrible winter and a cold, wet, and cloudy spring, June and July came along with some of the longest streaks of clear nights I can remember. Email messages from the Clear Sky Clock about an impending clear sky became routine. Many of us had forgotten what a clear sky looked like and found it necessary to re-learn the constellations before beginning our search for our favorite Messier and NGC objects. Suffcient sleep for the daytime routine was in short supply.

The BPAA has had a very successful summer and since I last wrote a President’s Message we have received a $50,000 challenge grant from the Seattle Foundation Birkenfeld Trust. Under the terms of the grant we have until next March to raise matching funds in the amount of $50,000 from other sources. Therefore, plans are underway to launchfund raising events in the fall. It will be essential that all BPAA members pitch in and help in any way they can to raise the needed funds.

Russell M. Heglund, BPAA Secretary and Parade Organizer, brandishing our “Funniest Float”award.

The Grand Old Fourth of July 2008 celebration was one to be remembered. Personally, I don’t care much for the Fourth. I hate the freworks because they scare my cat, not to mention that they cause fres and injuries. But this year the Fourth was quite something, even for a cynic like me. BPAA outdid itself with the help of a few alien friends who agreed to ride in the back of a 1980 BPAA pick-up truck and imbibe tropical drinks complete with teeny paper umbrellas. Even the parade judges were amused. BPAA won a trophy for the funniest entry. While this was going on the aliens were also soliciting new BPAA members at the BPAA booth by agreeing to go home with any new member. I guess kids and adults liked the deal and by the time our booth closed we had over ten new memberships.  For the more serious citizens we had planetarium shows in the afternoon. There are still a few aliens hanging out at the Observatory; we need to fnd homes for them.

The BPAA continues to serve our community by conducting planetarium shows and educational programs. I want to mention two that in my view were special this summer. The frst was our planetarium presentation at the Muscular Dystrophy camp for kids. We then supported Relay For Life, a cancer fundraising event. Special thanks to those of you who made these events happen.
I missed going to one of the major regional star parties this year for the frst time in over 10 years. My vision has deteriorated to the point where I can no longer see much through an eyepiece making it diffcult to align my telescope equipment. My problem will be corrected with surgery this fall. Meanwhile I will read about BPAA’s summer star party adventures in the Newsletter.

Mike Browning, BPAA Vice President & Archives Manager

In early July, the Seattle Foundation announced it has awarded the BPAA a challenge grant for $50,000 from the C. Keith Birkenfeld Memorial Trust. This lead position in the capital campaign allows the BPAA to kick off capital raising with a qualifed endorsement of our plans.

Over the coming months, the BPAA Capital Committee will be reaching out to membership and the community to complete the frst phase of fund raising for a total of $100,000. The funds will be used to provide improved facility accommodations and a remote robotic telescope. 

The robotic telescope capability has generated growing enthusiasm—it will allow 24/7 access through the Internet for everything from hands-on youth discovery labs to self-driven astrophotography. This activity builds on the successful history of the BPAA in providing unique and engaging programs to members and community.

Part of what has made the fund raising successful to date is a growing tradition of volunteerism. If you would like to volunteer to participate in the BPAA Capital committee or history and archival work, please contact vicepresident@bpastro.org and we will be sure to take advantage of your time and talents. If you would like to arrange for a gift for the BPAA, please contact the email above or call 206-861-1630 and you will be contacted promptly to ensure that you receive the non-proft tax deduction information.

Stephen Ruhl, BPAA Education Offcer

On July 21st, I made my second annual pilgrimage with the BPAA planetarium and dome to the Muscular Dystrophy Association’s Miracle Camp next to Horseshoe Lake Park, south of Port Orchard. MDA assists kids with various issues and provides them a good safe place to have fun for a couple of days. Many of these kids are wheelchair-bound and their disabilities inhibit them from many normal childhood activities. This camp allows them to escape and just enjoy themselves for a few days. The campground has a western theme with corrals, horses and a western town setup for all of the dorms. The camp is driven completely by volunteers and each camper has an aide to assist them with their needs.

The portable dome and the scene inside.

Last year, the BPAA was asked to put on a star party for the campers. After talking to the camp director, Leslie Boback, since many campers were wheelchair bound and most telescopes are not ADAcompliant, we decided a planetarium show was more appropriate. So I carted the planetarium down and did six shows to lots of enthusiastic kids. The planetarium was a real hit and some of the kids wanted to see it over and over again.

This year, they were more organized and I only did fve shows. But the results were the same. While most of the kids do not require wheelchairs, the planetariumallows us to show the wonders of the night sky to wheelchair-bound kids. We lift the side of the dome up and the kids drive themselves in. Then we wait for the dome to re-infate.

The kids themselves are wildly enthusiastic, moreso than the kids at our usual school shows. They want to see more and more and it is actually hard to get them to leave so we can get the next group in the dome.  The kids really appreciate the effort that all of the volunteers make for them and it shows. I’ll be there next year also.

Russell M. and Jody Heglund

The annual Bainbridge Island Bluegrass Festival was held Saturday, July 26th from noon until 8:00 p.m. Since they set up the music stage against the north wall of the BPAA Observatory, and the festival sale booths and honey-buckets were just outside of the Observatory main door, it seemed a good place and time to set up a BPAA information table. We put the table in front of the main door, fanked by a Dobsonian telescope and a refractor telescope. We trained the refractor on the park water tower, where an osprey family was raising young ones. Jody helped small kids look with our small step-ladder and answered questions.  It was very popular, especially after they announced the osprey viewing at band breaks. Scores of people came by. We passed out fyers, newsletters, and invited all to our Planetarium Show and Star Party that same night!

photos courtesy Sue Hylen

Nels Johansen and Malcolm Saunders spent some days repairing pesky leaks and rotten spots on the Ritchie Observatory dome.

photo by Paul Below

Paul Below and Russell M. Heglund

Mt. Bachelor Star Party, August 6–10: The frst day we had beautiful skies and no wind. We could see the Milky Way from horizon-to-horizon. There were a couple more clear nights, but cold—long-john weather— & windy—we had to anchor Dave Warman’s tent with chunks of basalt.

There were four talks this year. The frst was an engaging talk by Dave Powell on some Great Telescopes, or more specifcally, the wealthy and sometimes eccentric people who funded them. He described three of the great telescopes of history, and how they came to be, along with a biography of the person who supplied the funds.

The second talk was by Tony Leavitt, who is with NASA. He focused on the exploration of the Solar System and recent NASA missions. There were some technical diffculties setting up the talk. A number of current or recent missions were covered, but the talk’s disorganization made it the least memorable.

A composite view of the upper parking lot, where most people were set up, and BPAA’s digs just across from the lodge, including Russell and Jody Heglund’s 1984 VW van, shade tent, and telescope pad and Dave & Ann Warman’s tent. There were two large Dobsonian telescopes (on the right, half way down the parking lot) at the Star Party. One was a 20-inch diameter, completely hand controlled. The other was a 26-inch diameter monster, with motor drives and computer controls. Broken Top Mountain is just visible to the north of us. The lot is at about 6500 ft. elevation. Mt. Bachelor is about 9000 ft. at the top.

The third talk was on imaging by David Haworth. He described various setups that he uses to capture excellent images from his backyard, contrasting the different technologies and providing practical advice. He also covered the differences between shooting images for research and manipulating images to produce a beautiful result. He did some imaging at Mt. Bachelor and shared those as well.

The fourth and fnal talk was by Mel Bartels. Titled “where are they?,” it was an overview of various SETI activities in the past as well as speculation on why we have not yet detected intelligent life in our galaxy. The audience participated in a thought-provoking discusssion.

Stephen Ruhl

Globular Cluster M13

I have been interested in photography since childhood. Whenever a new experience enters my life, I document it via pictures. This interest expanded into an avocation. It was with deep regret this past year, I gave up all of my darkroom ways for digital photography.

My avocation for astronomy is almost as long. With my frst real telescope, an 8-inch Cave on a German equatorial mount, I made many attempts at astrophotography, with mixed to mediocre results. I tried a lot of different things, off-axis manual guiders, separate manual guide scopes, Kodak 103 flms, gas-hypered flms, various darkroom techniques. I built a CCD camera to boot. I came to appreciate the efforts of Edwin Hubble, stuck up in the prime focus cage (about 1/3 the size of a phone booth) manually guiding the Mt. Wilson 100-inch scope all night to measure the luminosity of  variable stars in Andromeda so he could determine the galaxy’s distance.

When I built my current 14 inch telescope, astrophotography was in the back of my mind. While az/alt mounts do have photographic limitations,  I found that I was still able to get reasonable photographs from them. The ‘scope saw frst light about a year ago. Over the course of the past year, it has evolved from a simple push-pull Dob, to a powered goto, to autoguided astrophoto telescope.

None of this is rocket science. It is basically just reading and doing research and then connecting the dots.

The construction of a Dobsonian telescope is well documented. My ‘scope is based on the work Doug Tanaka is doing building a 20-inch for BPAA. This is largely based on the book The Dobsonian Telescope: A Practical Manual for Building Large Aperture Telescopes, by Kriege and Berry. The mirror was purchased on eBay, some of the components were built from scratch, and some are from commercial sources.

The goto portion of the ‘scope is based on off-the-shelf components from Sidereal Technology, the same components that drive the Richie Telescope. I made minor modifcations to the base ‘scope. I replaced the original ground board and added an altitude wheel. A couple of ¼” aluminum plates hold the SiTech servo motors and gear reducers. The only other additions required were timing belts and pulleys. The SiTech Web site shows many installation examples and part sources. Tailoring them to the needs of a specifc ‘scope is a reasonable task. A neat little addition was adding a bluetooth serial adapter from the controller to the laptop controlling the telescope. Wireless is cool.

Globular Cluster M56

The next step to astrophotography involves confguring the telescope for autoguiding. I strongly recommend autoguiding. If you have a perfect equatorial mount with no periodic error and your atmosphere does not refract light or your photos are real short (< 15 sec), you might get away without, but do not go into astrophotography and not expect to need auto-guiding. It will not work.

Autoguiding allows for precise tracking for photographs. This technology requires a combination of components working together, including:
1. The telescope controller. The SiTech supports two versions of autoguiding, the industry standard hardware autoguiding ST-4 (requires the purchase of additional hardware) or a software version of autoguiding based on the ASCOM (Astronomy Common Object Model).

2. A guide telescope and guide camera. For the guide scope, I picked up 500mm f5.6 Celestron from eBay and an Orion Autoguider camera. Almost anything can fll these functions. A guide ‘scope that has the aperture of a decent fnder ‘scope is suffcient. Many people use web cams for guide cameras.

Dumbbell Nebula M27

3. Software to drive the camera and send ASCOM commands. Here the choice is easy: PHD Guiding. (PHD stands for Push Here Dummy). The software starts guiding by sending some commands and calibrating the movement. It resolves movements down to the sub-pixel by resolving normal distribution of star light across the sensor, doing basic statistics and tracking where the camera should be. This software works very well, and best of all, it is free.

So we attach the guide scope to the main telescope, plug in the USB cable, fre up PHD, and we are off and tracking.The next thing to consider is your camera. This is a huge topic: you need to balance your resources against what you are trying to do. I settled on a Canon DSLR largely because it can do double duty as a regular camera.However, DSLRs have major issues. They are not sensitive in the IR portion of the spectrum (you can have yours modifed but it is not cheap), they are not as sensitive to low light levels, and since they are not cooled, there will be noise issues.

Globular Cluster M92

A special-purpose astronomical CCD camera is a lovely thing. You can buy some huge, cooled detectors, with very low dark current and so on, but you will need to refnance your house. This is one of those spots where a hobby will take as much money as you are willing to give it. Did I say that these things can be expensive? Also, they are evolving so rapidly that your expensive toy becomes obsolete in six months.

Another huge topic for the future is image processing. Most pictures are composites of multiple pictures that are digitally enhanced to bring out detail, using the available photons to create an image that can display what is physically there, but your eye cannot resolve.

Read and research. Check out Shoestring Astronomy, Stark Labs (PHD) and Richard Berry. Checkproduct specifcations from the manufacturer and other sources. Read some Internet bulletin boards. There are all sorts of mundane details that may infuence your choice of equipment. For example, I chose Canon over Nikon because of their superior RAW fle technology. (DSLR use RAW fles store data without compression or data loss.)

You will need to know some detail about different digital photographic encodings.  JPEG is not used because it compresses, and loses, a lot of information. The standard is FITS (Flexible Image Transport System), developed by NASA. It can store image data in a variety of ways: 8-bit, 16-bit, 32-bit, foating point, and in multiple dimensions.

All in all, I get a good deal of satisfaction taking decent pictures of what I am seeing (actually more than I can see.)

I took the images accompanying the article over the summer from my driveway. The site has horizon issues and in addition to the street light at the end of the block, all of my neighbors insist on leaving their porch lights on all night (like some one is going to come and visit you at 3 a.m.). The processing makes it possible to see things that under typical suburban conditions would otherwise be invisible.

Image courtesy History of Science Collections, University of Oklahoma Libraries

Anna Edmonds
How did the constellations get their names? The Big Dipper and the Little Dipper are obvious; they look something like ladles. But does Aquila look like an eagle?  And where did the star names come from? 

Deneb in Cygnus means "the hen's tail" which makes sense because it's in the tail of the swan. But then Vega in Lyra means "the falling eagle."  What is an eagle doing falling in a harp?
There are four minor autumn constellations between Cygnus, Aquila, and Pegasus.  They include from north to south, Vulpecula, the Fox; Delphinus, the Dolphin; Sagitta, the Arrow; and Equuleus, the Foal.  Two of them, Sagitta and Delphinus, have some resemblance to their names; the other two don't.  None of them has a star brighter than magnitude 3.5.

Of these four, Equuleus is the second smallest of all the constellations. (Crux, the Southern Cross, is smallest.) It lies on a level with Aquila and sinks below the western horizon shortly after that constellation does in early December. Its Latin name means "the little horse."  It is listed in Ptolemy's 2nd century BC catalogue of stars. Equuleus contains some interesting double stars such as ? Equ and ? Equ. In mythology Equuleus was the foal of Pegasus that Mercury gave to Castor. Later Equuleus became a master musician. What instrument do you think a horse would play

Vulpecula is located just under the eastern wing of Cygnus. The constellation enjoys the distinction of including M 27, the impressive Dumbbell Nebula, listed by Charles Messier in 1764. (You can see Steve Ruhl's photo of it on page 6.) It also contains the star cluster called the Coathanger or Brocchi's Cluster.  Except for the constellations in the southern hemisphere, Vulpecula is the newest constellation to be identifed. It originally was named Vulpecula cum Anser, "the little fox with the goose," by the Polish astronomer Hevelius in 1690. Being so recent, it lacks a Greek myth. Its goose has long since fed, except that one of the stars in the fox's jaws still sometimes keeps the name Anser. Would that be the bird's tail feather?  The frst identifed pulsar, PSR 1919+21, is in Vulpecula.

Incidentally, the names of constellations and their boundaries varied from country to country until 1933 when the International Astronomical Union got an agreement that divided the sky into 88 specifed constellations; that agreement also established their boundaries according to meridians and parallels.

Sagitta includes the loose globular cluster M 71 near d Sge, and U Sagittae, which is an eclipsing variable star.  Sagitta in mythology is variously identifed as the arrow that Hercules aimed at the eagle which was eating at Prometheus, or the one that Apollo used to get rid of the Cyclops, or it might be Cupid's.

Delphinus has been identifed as a constellation since ancient times.  It is supposed to be the dolphin that helped Poseidon, the god of the sea, woo the nymph Amphitrite who then became his wife and the queen of the sea.  In thanks, Poseidon awarded the dolphin a place in the sky. (To be clear, one of Jupiter's moons is also named "Poseidon," and the god himself is also known as Neptune.) The name Delphinus is also associated with a number of stories of dolphins that have befriended people, and with several statues of children gleefully riding dolphins.

An early 19th century Italian astronomer, Niccolo Cacciatore, has fgured in a bit of a puzzle involving Delphinus.  He worked at the Palermo Observatory in Sicily under its frst director, Guiseppi Piazzi, when Piazzi was publishing his defnitive list of stars in 1814.  (For this Piazzi was awarded the prize of the French Academy of Sciences.) Cacciatore is thought to be the man who gave the two brightest stars of Delphinus the curious names Svalocin and Rotanev.

Not much is known from the records about Cacciatore except that he succeeded Piazzi as the Observatory director in 1817. But those names raise some questions about what sort of a fellow he was. Like all well-educated 19th century westerners, Cacciatore must have been fuent in Latin, so he would have known the Latinized version of his name, Nicolaus Venator.  And, like all professional astronomers, he would have observed the retrograde movements of the planets.  Perhaps he spent his childhood summers swimming and fshing in the sea? Palermo is situated on the coast of the Tyrrhenian Sea where there is even still a concentrated diversity of porpoises, dolphins and whales. Many 19th century astronomers questioned the meaning of those names, but it took forty years before the British amateur astronomer, Thomas Webb, realized that Cacciatore had worked retrograde into his star names by spelling his Latin name backwards. Could this have been his thanks to some dolphins he had played with?

Jupiter in a Cassini image taken 29 December 2000. The surface visible here is the cloudtops in an atmosphere of (mostly) hydrogen and helium. Most of Jupiter’s volume is liquid hydrogen. (Credit: NASA, JPL, Space Science Institute)

Ted S. Frost

Earth’s early history 4.5 to 3.5 billion years ago is diffcult to reconstruct, since practically all geological evidence has long since been obliterated. Nevertheless, recent computer simulations and geochemical discoveries have revised Jupiter’s role in Earth’s formation and life’s creation.

Jupiter has traditionally been considered Earth’s guardian. Its massive presence at 5.2 Astronomical Units (AUs) from the sun was seen as a giant shield defecting incoming comets and asteroids from Earth. Recent studies¹, however, conclude Jupiter’s existence might actually have increased chances of Earth being hit by extraterrestrial missiles. According to these studies, Jupiter’s existence is now considered the main cause of Earth’s Late Heavy Bombardment, the period some 3.9 billion years ago when Earth was subjected to intense pummeling from comets and asteroids.

Earth has always had uninvited ‘visits’ by extraterrestrial objects, but the Late Heavy Bombardment was particularly nasty. Planetary scientists have wondered why this extraordinary event occurred 700 million years after the solar system had formed, and why it was so brief. Its peak is estimated to have lasted less than 100 million years, with precipitous drop-offs before and after. According to recent computer simulation analyses², the Late Heavy Bombardment was caused by reorientation of the orbits of the giant planets circling outside the inner planets. The most infuential player was Jupiter, whose mass is 2½ times that of all the other planets combined. According to these analyses, planets in our solar system evolved relatively quickly some 4.6 billion years ago out of a revolving disk of solar nebula dust and gas. The four rocky inner planets—Mercury, Venus, Earth, and Mars—were within a few AU’s from the Sun. Beyond Mars was the asteroid belt, orbiting debris prevented from accreting into a ffth inner planet by the overwhelming gravitational infuence of the gas giant Jupiter.

Beyond Jupiter, but within 15 AU’s, were the gas giant Saturn and the two ice giants Uranus and Neptune. Beyond them were thousands of planetesimals made of material that hadn’t been able to coalesce into full-fedged planets, rocky objects large enough that their own gravity held them together.

Migration of planets within a developing solar system is accepted, but imperfectly understood. Initially, migrations are believed to be caused by competing gravitational torques from surrounding disks of orbiting gas clouds. After heat and stellar winds dissipate a solar system’s gas clouds, planet migration is thought to involve exchange of angular momentums between passing accreted objects.

As the planets in our solar system matured, planetesimals that wandered too close to one of the growing outer giants would be caught in its web of gravity and fung aside. For every action there is an opposite and equal reaction. Tossing a planetesimal aside gravitationally causes the tosser to be nudged the opposite direction. Jupiter was too huge to be greatly affected by this phenomenon, but Saturn, less than a third the size, began slowly spiraling outward.

Initially, Saturn’s orbital period was less than one half of Jupiter’s. But after 700 million years of planetesimal clearing, the migrating orbits of Saturn and Jupiter reached a resonance point whereby their orbital periods (OP) achieved a 1:2 integer resonance ratio³. That is, OPs/OPj = 2, causing Saturn and Jupiter to be in lockstep and their orbits to become eccentric. This transition caused, as Hal Levison of the Southwest Research Institute puts it, "all hell to break loose."

The transitional event destabilized the orbits of the four outer giant planets resulting in close encounters and pushing Uranus and Neptune outward into their present orbits at 19 and 30 AUs. Orbits of the outer planetesimals were violently destabilized, most being scattered hither and thither. In addition, the transition strongly perturbed the asteroid belt, driving many into orbits with eccentricities and inclinations large enough to intersect the inner planets. Hence, the Late Heavy Bombardment, whose consequences can be seen today in the form of the large dark basins on the Moon, as well as impact craters on Mars and the Caloris basin on Mercury. 

With such a catastrophic pummeling 3.9 billion years ago, what about life on Earth? There is strong microfossil and isotopic evidence that prokaryotic life existed on Earth by at least 3.5 billion years ago. There is also good geochemical evidence that 4.2 billion years ago Earth was relatively cool with liquid water and continents.⁴ Presumably, Earth’s environment was conducive to life around the time of the Late Heavy Bombardment. If life did or could have existed at that time, what happened?

One would think a steady rain of meteorites would be devastating, but some scientists are beginning to think it was just the opposite. Instead of being a destroyer of life, they suspect the Late Heavy Bombardment actually helped make life possible by bringing organic materials and essential chemicals to Earth. Matthew Pasek, of the University of Arizona and NASA Astrobiology Institute, has theorized that the key element phosphorus was delivered to Earth by iron meteorites impacting Earth during the Late Heavy Bombardment.⁵

Life’s primary essential chemical elements are carbon, nitrogen, oxygen, hydrogen, sulfur, calcium, and phosphorus. Of the seven, phosphorus is by far the hardest for life to come by on Earth. Such phosphorus as does exist on Earth is primarily locked up in mineral forms such as apatite that are basically inaccessible to living organisms. But all life-forms use a molecule called ATP (adenosine triphosphate) for an internal energy source. The three interconnected phosphorus atoms in the ATP molecule have unstable covalent bonds, easily broken to produce small packets of energy for the organism. Without ATP, life as we know it would not exist. Without phosphorus, ATP would not exist. Phosphorus also plays a role in DNA, RNA, and cell membranes. But, geochemically speaking, on Earth, phosphorus is not available for organic uses. So how did life acquire it?

Pasek and his team suggest that the reduced forms of phosphorus used by living organisms was delivered extraterrestrially by iron meteorites. Metallic meteorites hitting Earth are largely iron cores of broken up planetesimals and contain abundant amounts of a mineral called schreibersite, an iron-nickel-phosphorus compound, (Fe,Ni)₃P, that is rare on Earth. 
Upon impact and exposure to UV light and water, much of a meteorite’s schreibersite phosphorus converts to reduced forms. All that was needed for biologically useful phosphorus to be delivered to Earth was something to break up cosmic debris and herd it towards the inner planets. That appears to have been Jupiter.⁶  Assuming our solar system’s geochemistry is typical, this suggests an appropriately placed planet the size of Jupiter might be necessary for life. If so, existence of liquid water might not be the only thing astrobiologists should emphasize when searching for extraterrestrial life.

Footnotes:

1. J. Horner, European Planetary Science Congress in Potsdam, 2007.
   
2. R. Malhotra, "Dynamical Cause of the Late Heavy Bombardment," Lunar and Planetary Science XXXVII, 2007.
   
3. R. Gomes et al, "Origin of the Cataclysmic Late Bombardment Period of the Terrestrial Planets," Nature 435; 466-469, 5/26/05.
   
4. M. Menneken et al, "Hadean Diamonds in Zircon from Jack Hills, Western Australia," Nature 446, 8/23/07, and J. Valley et al, "A Cool Early Earth," Geology 30, 2002.
   
5. M. Pasek, "Rethinking Early Earth Phosphorus Geochemistry," Proceedings of the National Academy of Sciences, vol. 105, 1/22/08.
   
6. J. Bailey, "The Inner Solar System Cataclysm, the Origin of Life, and the Return to the Moon," Proceedings of the 6th Australian Space Science Conference, 2006.

BATTLE POINT ASTRONOMICAL ASSOCIATION
P.O. Box 10914, Bainbridge Island, WA 98110
http://www.bpastro.org/
Ritchie Observatory, Battle Point Park
(206)842-9152

Officers
Harry Colvin, President
(206)842-6617, hcolvin1@comcast.net

Mike Browning, Vice President
(206)861-1630, bjjm@qwest.net

Russell M. Heglund, Secretary
(206)842-8758, rmheglund@yahoo.com

Frank Schroer, Treasurer
(206)842-1974, frank@schroer.net

Nels Johansen, Facilities Officer
(206)842-7968

Stephen Ruhl, Education Officer
(206)855-7883, education@bpastro.org

Malcolm Saunders, Chief Astronomer
(206)780-1905, astronomer@bpastro.org

Edward M. (Mac) Gardiner
President Emeritus/Founder
(206)842-3717, macg@bainbridge.net

Ed Ritchie, Chief Astronomer/Founder 1993-1997

John H. Rudolph, Facility Director/Founder 1993-2003