Friday, August 31, 2007

Use the lights in the sky ...

Essential aids for timekeeping and navigation. Insert lots of AI devices to track celestial objects and keep habitat on track.

--Unique vantage points.
--Earth views from different perspectives
---assist Terran and Lunar observations via pointers and parallax measurements.


Sidebar: Dark Side of Moon Ideal for Observatories..

(Note extract from "Entering Space, Creating a Spacefaring Civilization", wonderful book by Robert Zubrin. Slight changes to reflect my readability, no intent to change content. Content belongs to Mr. Zubrin, misteakes belong to me. Jim O)

Moon's dark side would be a superb vantage point for astronomical observatories. It has no obscuring atmosphere, and it rotates only once every 28 days; thus, a scope could collect 28 times more light from a distant object as possible on Terra (400 times that of Low Earth Orbit, LEO, satellites such as the famous Hubble space borne telescope). Moon is seismically inactive and provides a rock steady platform for mounting telescopes. This steadiness anables optical arrays of scopes to focus on a single object and coordinate signals via computer (interferometry). For extreme resolution, distances between component scopes must be accurate within a micrometer (impossible in the seismic active Terra, even less possible on a LEO satellite). Recall the telescopic resolution is proportional to its diameter; thus, an array of scopes has theoretical resolution many times that of a single scope (only one component of the overall array). The dark side of the moon gives a potential diameter of 1,700 kms (many thousand times better than Hubble satellite which has yielded many breath taking images with incredible resolution.)

While impressive, the above capabilities are really the tip of the iceberg. In additon to optical, airless lunar surface would enable other spectrums: cosmic-ray, gamma-ray, x-ray, and ultraviolet. Luna's permanently shadowed craters provide constant low temperatures for continual infrared observations. Shielded from Earth’s multitude of Radio Frequency (RF) transmissions, dark side of Moon enables radio telescope observations. Lack of ionosphere further enhances this RF capability.

Perhaps some of these benefits would also be on asteroids transformed to habitats.





Stars - excellent nav aids, definition of beacon.

Sidebar: Whether God created these beacons to guide the human race or God created the human race to take advantage of his beacons, I'll gladly leave such theological arguments to the theologicians. Trying to fathom God's intent is much harder then an ant trying to understand the thought processes of a human, and why we continually try to do this is a mystery to me.

Stars are like lighthouses, they not only provide an excellent target, but they also might help travelers avoid hazards. What hazards?? Let's speculate.

How do interstellar travelers avoid gravitational fields of enroute stars?
Once humans start performing interstellar travel, avoiding enroute stars will not be a problem for many years for following reasons:
1. Initial trips will by necessity be to adjacent stellar systems; thus, there won't be any "enroute stars" because the destination star is the closest one in that direction.
2. Even when our interstellar capabilities enable trips past "enroute stars", stars produce so much light in the visible and other spectrums, that interstellar habitats ("migrators") will easily notice them and avoid them. As a matter of fact, such enroute stars would be welcome navigational beacons.
3. As a matter, the best enroute beacon will be the destination star.
----Direction (confirmed by departure star)
----Sizing
----Neighboring stars and other celestial objects will provide many Lines of Positions (LOPs) to confirm position on interstellar "track" from dept to dest.

Thus, we should be able to avoid stars that we can see, what about interstellar objects that we can't see???
1. Black holes would be invisible til too late to avoid. The only reason that we can detect them now is due to their effects on nearby stars and star matter. Interstellar travelers could only detect it if it obstructed known star.
2. Brown dwarfs emitt low levels of radiation and would be hard to detect.
3. Rogue planets/planetoids/planetisimals emitt no light and could be detected only by reflected radiation.


A thoughtful man once hypothesized that the universe must be finite, because if there were an infinity of stars then Earth would never know the darkness that we call "night". An infinity of stars would mean that every spot on Earth would have a source of visible light (one or more stars) at its zenith and ensure a continual source of light to evey point on Earth's surface. Of course, we do indeed experience night as part of our daily cycle; so, the quantity of stars is finite, and the Universe has limits.

Of course, modern science now accepts the "Big Bang" theory of creation to would put the age of the Universe at 15 billion years (give or take), and the diameter of a spherical Universe could be about 30 billion light years (assuming expansion from some "central point" at the speed of light).

Granting these limits of the Universe, there are still sufficient stars to light up the Earth at night. In our galaxy, Milky Way, there are at least 100 billion stars. There are 100 billion galaxies which probably average 100 billion stars each which gives us 10**22 stars, again more then sufficient to light up every square inch on Earth. Yet, we still experience a lack of light at night, how come??
1. Distance.
2. Dark Matter.
3. Singularities. At last, we come to a hazard to our interstellar habitats. Stephen Hawking hypothesisized that black holes (i.e., singularities) are spread out throughout space. As a matter, he hypothesized an average of one singularity per cubic light year. What are the chances of a singularity being close to an interstellar track between Sol and possible stellar destinations, enough for concern??

If light comes to us from a star, there is not a black hole directly between us and that star, because a black hole would have absorbed the light. Thus, if we see a star, we can proceed directly to it and not have to worry about black holes. Thus, stars make great lighthouses.

That's why traveling directly to a stellar destination is so important. If there was a singularity near that route of flight, light from the target star would show some anomalies.If we travel directly to our stellar destination (i.e., beacons), we'll likely avoid these black holes because a black hole directly between us and a star would absorb all the light and hide the star from us. Since we observe the light, the singularity must not be near.

Is there a black hole near the Solar System? If there was, how would we know? To discuss this further, let's Google: "Astronomy Nemesis" for hundreds of hits. Two are paraphrased below.Star Perturbations and Nemesis Theory .....physicist, Richard A. Muller, and others have postulated a stellar object, Nemesis, with a highly elliptical Solar orbit well beyond the Oort cloud. This object is theorized to pass through a portion of the Oort cloud approximately every 26 million years; thus, bombarding the inner solar system with comets. Although the theory has many proponents, no direct proof of the existence of Nemesis has been found.

DEATH STAR THEORY refers to Earth's periodic mass extinctions which may be caused by a cloud of comets (from the Oort cloud) every 26 million years. Some people have hypothesized a not yet discovered dark star or perhaps a planet (prenamed: Nemesis) orbiting in the outer reaches of our solar system.

My thots: I recall reading that historical astronomers have hypothesized on a very large object orbiting beyond Neptune based on observed perturbations of Neptune in its orbit. Searching for this object, Percival Lowell discovered, Pluto, now considered to be a large Kuiper Belt object, but certainly not large enough to have perturbed Neptune's orbit. Perhaps Nemesis caused these perturbations. Perhaps continuing perturbations might help us find Nemesis.Much effort have gone into searching for Nemesis, but of course there's a lot of sky to look at, and a dark object (very large planet, brown dwarf, black hole) would not radiate very much to help us find it. As a matter of fact, it could be detected by an absence of light. For example if a well established star temporarily vanished, this would be a clue that Nemesis passed in front of it. Unfortunately, such a sighting would likely be considered "noise" or an observational anomaly. Of course, since we have no idea where or when to look for such phenomena which would likely be ignored as "nondata"; chances of observing this are very slim.

Let's assume the Good Lord favored us with such a sighting, and some astute graduate student decided to follow up on it. We would then want to find a second sighting to establish a trend to predict subsequent sightings. After several observations of stars vanishing then reappearing, then an orbit could be calculated and much more data collected.

What a great SciFi story! A ship accelerates at g for 300 days, attains .866c, and cruises for a year toward a destination star. Then, the destination star dissappears! Well, stars can explode, but they can't just dissappear with no accompanying phenomena; thus, we're sure the star is still there but something has interposed itself between us and the star. Since that object is not radiating anything for our sensors to analyze, IT MUST BE A BLACK HOLE!!!

For the rest of the story, wait a couple of years while someone writes the book.

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