JUNE08T
SpaceWalk
FOR JUNE 2008
------------------------
John Pazmino
National Space Society
New York City Chapter
Readers went totally gag over the
May 2008 SpaceWalk! So the announcement of the next train stop is controlled by
a FACILITY OPERATED IN OUTER SPACE?!?! Yes, but the M7 model of coach is
peculiar for LIRR and MNR. I don't know about other rails.
The point was that we rely on space operations to such a deep
extent, that it's more and more likely that some simple and trivial aspect of
your daily life is linked to outer space. When the link gets out of joint, like
it did on 26 February 2008 for the GPS grid, your daily routine can suffer
major diversions.
It is really necessary to be aware of the present ongoing
benefits (and malefits!) of outer space in human society to conduct a credible
advocance for space projects. You can not and must not confine to just the
futuristic dreams, as if there is nothing up there for us now.
How to acquire such awareness? Here are two ways. One is, I admit, a bit
much for many space enthusiasts. The other is so trivial I'm amazed that it is
so completely neglected.
First, the hard way. If you got an interest in one or more of a
wide assortment of sciences, you should take in meetings, conferences, seminars
related to that interest. In my own case I attend meetings for astronomy. Many
are really technical and academic, like the 'New trends in astrodynamics' conference
chaired by Dr Edward Belbruno. The 2006
and 2007 meetings were in Princeton University; the one for 2008 is in Italy.
Frankly, many of the presentations at the Princeton events,
both of which I attended -- and gave talks at! -- were, uh, over most of our
heads. Yet, many were glatt spacefaring in as much as a major application of
Belbruno's technique is for spaceprobe trajectories.
On 2008 May 9, I, with a couple chapter and NYSkies members,
took in the 'String theory' conference on Manhattan. This is a really obtuse
event, for most of us. But there was some intriguing application of spacefaring
in one of the papers, which I summarize a little later. A nice touch was that
the conference was free and included lunch! So even if you got nothing at all
for the mind, your stomach was filled.
For the easy way to keep in touch with spacefaring benefits,
there are the magazines in your other interests. Regularly read one or two of
your interest's major periodicals. For me, it's the literature in astronomy.
One which has almost monthly good wood about spacefaring in 'Sky at night',
from England.
This is a complement to the BBC monthly television talk show,
hosted by Sir Patrick Moore. Besides the printed paper content for astronomy,
the zine sports a CD glued to its cover. This disc has enhanced content, like
computer images from the photo gallery section of the magazine and a video of
the 'Sky at night' telly show. It also has extra items, such as an astronomy
software and a narration about the night sky [as seen from England].
I get the issues from the superstores of Barnes & Noble
around Manhattan. It's $8.75 per ish, including the cover CD. This is,
surprisingly, not a stiff price for a magazine. It's hard to see others for
less than $5 and there are lots for up to $15 each. As far as I know, 'Sky at
night' is the world's only astronomy magazine with a computer disc enclosed,
altho computer, music, and art periodicals have such discs. The May 2008 issue
happens to be full of spacefaring gumbo, as I detail here.
Let's look at string theory. I know almost nothing about the
workings and meaning of string theory, a state of affairs that ranks me among
the greatest string theorists of the world. So I won't trouble you with that aspect
of the meeting.
One presentation at the String Theory session would make a spacefarer drool. It discussed the dependence of dark matter studies on spaceprobes! This talk also covered spaceprobe studies of dark energy and accelerating Hubble expansion. I here detail just the dark matter.
This lecture, given by Dr Steve Allen of Stanford University, relates to X-ray emission from galaxy clusters. We met two galaxy clusters in the May 2008 SpaceWalk, the Coma (KOH-ma) and Virgo (VIRR-goh) clusters. In a regular photograph, the cluster consists of scores to hundreds of galaxies bunched within a few diameters of each other. Here's a photo of the Hercules galaxy cluster, about 650 million lightyears away. Every spot with definite texture is a member of this group. The very tiny ones are background galaxies.
By their similar texture, size, and redshifts we know the galaxies belong together and are not just lined up by chance. They are also confirmed as a group by their mutual gravity that induces local motions among them.
Now comes the nasty part.
The gravity needed to move the galaxies around as we observe them
to do is much, much greater than the mass of the visible matter of the galaxies. This was first surmised in, believe it or not, the late 1930s. At that time study of galaxies was still young, with galaxies being recognized as such only a decade earlier. We assumed that larger telescopes, better instruments, fancier analysis will remove the discrepancy. They didn't.
By the 1960s, the excess gravity was still with us and became known as the 'missing mass' problem. The only way we know to generate gravity was by physical matter, a la Newton's theory. The new larger telescopes and more sensitive photography and imaging of the 1960s and 1970s revealed faint extensions of the cluster's galaxies. The extra mass in these regions was no way close to making the excess gravity.
So far, all observations were made from the ground, where all the observatories were until the 1960s. Astronomy use of outer space was only just beginning. One of the pressures to exploit the space environment in astronomy was to get rid of the absorbing distorting effects of Earth's atmosphere.
By the 1970s we were fielding satellites to examine parts of the electromagnetic spectrum not 'seen' before. Some of our theories and hypotheses about celestial radiation included wavelengths beyond what made it thru the air. Until we got above the air we could not test these ideas. One section newly opened for view was the X-ray zone.
X-rays are a region of the spectrum in the kilo-electron-volt energy band, of much shorter wavelength than ultraviolet. One way to produce X-rays is by heated gas, like that between and around the galaxies in a galaxy cluster. In fact, this gas, hydrogen with a splash of helium, was discovered by X-ray satellites. The heating is caused by the internal gravity of the cluster compressing the gas into a sphere around the cluster's core of galaxies. Here is an example with the Coma cluster. It's a composite of X-ray distribution from the ambient hydrogen, reddish, and the optical galaxies, bluish, in the middle. See how, despite the irregular deployment of the galaxies, the gas is more or less rounded?
Dr Allen explained that this gas was never processed in stars or other astrophysics method. It is representative of the cosmic material at the cluster's distance from us. It envelops the cluster far beyond the compass of the group of galaxies in the middle.
A wonderful feature of this gas is that it is an 'ideal gas' whose properties and behavior can be studied with simple gaso- dynamics. For the very large clusters, the influence of the core galaxies is small, leaving for us a clean relaxed sphere of hydrogen.
By modeling the gas and matching the results against the X-ray images from, in Allen's case, the ROSAT and Chandra satellites, the mass, density, and linear dimensions can be figured out. It turns out that the gas has 5 to 6 times the mass of the galaxies. Since we believe we now captured all of the 'luminous' material in the galaxy cluster, we can compute the gravity regime of the cluster from it.
By 'luminous' we mean that the material is detectable is any wavelength of radiation, not just optical light. A better term may be 'radious' and the gas has a 'radiosity'. All luminous matter consists of atoms, which produce radiation by well-understood physics. Atoms are baryons. That's why you may hear of 'baryonic matter'. It sounds so scientific when all it means is 'stuff made of heavy things'.
When we factor in all the gas plus the galaxies, we still find a deficit of mass to generate the observed gravity agitating the galaxies. There must be associated with the cluster an ADDITIONAL 4 to 5 times more mass. This is 'dark matter'.
Another way to get at the complete gravity and mass of the cluster is to look for lensing of remote targets. Radiation is deflected by mass, as Einstein predicted and Eddington found in the solar eclipse of 1918. The deviation is minuscule but recognizable in the curde images of far off targets behind the cluster. Here isan example of lensing by a cluster named CL2204+1654, which stands some 5 billion lightyears away. The bluish arcs centering on the cluster's own galaxies is the image of a far more distant galaxy.
The images are optically terrible. At first they ere taken to be disorganized material near the cluster. By studying their spectrometry and photmetry, it was realized that they are parts of a single original stream of light that was distorted by the Einstein effect. Even in this miserable image, you can guess that the far away fellow may be a spiral galaxy.
The mass to create these images includes all gravity sources, not just the luminous matter. Subtracting the luminous matter, the galaxies and unconsildated gas, leaves the dark matter.
No one knows WHAT this dark matter consists of. It could be regular atoms which for some reason aren't radiating in any part of the spectrum. Or atoms radiating too weakly for us to detect as yet. Or it could be some new substance we now know nothing about.
The range of suggestions for dark matter is wide. You may read about dense clouds of neutrinos to weakly interacting massive particles, the so-called WIMPs. The former have infinitesimal mass but could heap up in fantastically immense quantities. Neutrinos also interact with ordinary matter almost not at all. The latter are a made up object with attributes to make them invisible and massive.
This whole discussion by Steve Allen hangs completely on the ability to observe, monitor, study X-ray radiation from bases in outer space. Celestial X-rays cannot be studied from the ground at the bottom of the atmosphere because they are blocked. Allen banked mostly off of Chandra data because of the probe's wide spectral range and detailed images. Other X-ray satellites, like ROSAT and XMM-Newton, supplement Chandra's work.
You may not have heard much about XMM-Newton. It's an ESA project, often missed out of American spacefaring news. 'Sky at night', from England, suffers no such hang-ups about foreign projects. It gives even-handed press to both American and overseas space efforts.
Another point is that Chandra and XMM-Newton do NOT compete against each other. They work together as a team. Their instruments are a bit different, the better to confirm each other's observations.
Chandra is one of NASA's Great Observatory missions, along with
Hubble, Spitzer, and Compton. Its pictures are just as awesome as Hubble's and grace many a spacefarer's walls. Because they are captured in an invisible spectral zone, the images cannot depict the targets as we would see them by eye
They are given interpretative or representative colors, like those on maps or graphs. The choice of colors is up to the astronomer who collected the picture, as best suits his project. Hence, it is tough to compare separate pictures by their colorations. A blue region in one picture may have a very different significance from a blue region in another. It's like forcing a correlation into a blue section of one geographic map with that in a map from some other author. Or imposing a meaning if the other map has no blue color in it.
As I noted, some of these meetings can be pretty scholarly, even if balanced on a string. I can understand if you may feel skittish about going to one, in spite of a free lunch.
I do include such meetings in my NYC Events column, posted each month at www.nyskies.org, because a lot of my readers can and do appreciate the dialog at these events. These folk are campus and home astronomers, engineers, techicians, or otherwise trained or skilled in the sciences.
OK, let's sit down for some reading and key pecking. Peel off the CD from the May 2008 'Sky at night'. It's attached by thin bands of sticky goo in the lower left corner of the cover, shown here. Pull slowly and carefully. If the disc case is cracked, like from rough handling at the bookstore, you may replace it with a good one later. The CD has many items that will nourish your spacefaring hunger for a few weeks, until the next issue comes out.
First, there's a photo gallery of Mars. The pictures, taken from orbiting and roving Mars space-probes, show changes on the planet. These are caused by weathering, outgassing, landslides, ice layering, and so on. Most pictures have two scenes to show the alteration over time. Some change occur within seconds; others, many years.
The pictures are ordinary computer files. There's a button on screen for you to save the pictures, which you may use in your own space promotion lectures. The detail is amazing. One picture of a Mars rover, taken from orbit, has features to the centimeter size!
If you like building models, the disc has masters for making the Spitzer infrared space telescope. Print them on stiff paper, better in color, then cut apart the pieces. Follow the accompanying instruction to fold and glue the model together into a realistic solid Spitzer satellite. Show it off at a chapter meeting, yes?
One target for a possible human base on the Moon is Shackleton crater, where there may be frozen water for visitors to live off of. The crater parapets are almost always in sunlight to supply electric to power the base. Sit back and watch a CD's animation flight over the crater. Be careful. It's the blackest of black of darkness inside. The Sun never gets into the cavity to melt or sublime the water.
If you want to track the Moon and learn some of its selenography (there's no 'geography' on the Moon), install Lunar Calculator from the CD. Set your home location (New York for us in and near the City) and time-zone. There after, you can see what the Moon is doing, her phase, location in the sky, surface features. The display factors in the wobbles and wiggles of the Moon. A crater near one edge tonight may be farther into the disc a week later or displaced round to the far side.
Where is Shackleton? It's so close to the lunar edge that it can be shifted over to the far side. The scene here was captured on July 2nd, when the tilt of the Moon brang Shackleton into view, within the blue oval, right on the very 'top' -- the south pole -- of the Moon.
If you got a limited view of the sky from a window, Lunar Calculator can figure out when the Moon is within that view! What crater is that flat broad one? Slide the cursor over it to get a readout about it. Need a telescopic view? Zoom in for the fine structure overlaid directly from the Celentine satellite maps.
You examined a certain crater last night with a telescope. When will that crater again have the same lighting for a second look? A button press sets the display to that date and hour.
The edition on the CD has a few curtailed features, yet is good enough for almost any purpose you have. For an unrestricted program, the author asks a small donation.
You like movies? After seeing 'In the shadow of the Moon', 'Sputnik mania', 'When we left Earth', what's next? Try 'Sputnik's children' or 'Return to the Moon' on the CD. In 'Sputnik's children' Sir Patrick narrates about designing and building satellites, with a walk thru a satellite fabrication lab and simulations of satellite paths in the sky.
'Return to the Moon' is the complete hour-long Sky at Night show from March 2008. Sir Patrick catches the February lunar eclipse and jumps off to various topics about the Moon. He touches on European space missions and a peek at the NASA human flights of the future.
I suggest you copy this file from the CD to your hard disc, a much faster fetch & read device than the CD drive. On my rig the show plays for about 15 minutes, then sputters. A work-around when the movie coughs is to note where the progress bead sits and then quit the video player, like QuickTime. Restart the 'film', slide the bead to its previous position, play the movie from there.
Apart from refreshing your basic astronomy of the Moon, you'll learn about some really good and rational plans for lunar exploration. Did you know that the instruments in the Beagle-2, that got smashed on Mars, are being remade to place into lunar landers?
Maybe you're itching to fly a space mission? If you lack the moolah for a ride to ISS, plausibly so with our slugging and sagging economy, sit in the commander's seat on the Space Shuttle. The Space Shuttle Mission 2007 simulation on the CD doesn't play just yet, You have to purchase it, with a pleasant discount, and get an activation code. Install it anyway and exit. Then, from its directory on your hard disc, read the quick-start book for details. It gives a thoro description of the program, to better inform you for a purchase.
This software needs a muscle computer of at least Windows XP strength. It bombs out on my elderly Win2K box. The book explains the system requirements, with special notes for low-horsepower laptops.
While waiting for the two programs to install, flip thru the magazine. You got a discourse about the Phoenix mission to Mars and a tour of the Moon thru a full lunation cycle. The May issue has a mite more spacefaring in it than usual. Each month has some, all fun to muck around with and sweeten the $8.75 damage. Remember the videos of astronaut interviews we saw at our April meeting? They came from previous issues of 'Sky at night'.
I remind that the two examples here, the 'String theory' meeting and the 'Sky at night' magazine, are those convenient to me as the astronomer. There are parallel opportunities in fields like geology, archaeology, wildlife and resources studies, natural disasters, geopolitics, meteorology and climatologic, boating, and navigation, land management, urban planning. That's only a few off of the top of my head at the instant. You'll be surprised at how pervasively these endeavors rely on space operations for their day-to-day function.
Well, we spent a big piece of time indoors. It's time to get on our monthly SpaceWalk thru the panorama chart. It's for 2008 June 20, the summer solstice, at 21h EDST. We're looking west, with zenith near top center. You may see fewer stars than plotted if the air is the typical New York summer one full of heat, humidity and haze.
About 1/3 up in the west are the planets Mars and Saturn, flanking Regulus (REH-guh-lus). Saturn is creeping east, away from Regulus. Mars is plodding east to pass Regulus and then catch up to Saturn. Mars reaches Regulus on July 2nd and kisses Saturn on July 10th. Until then, keep on eye on these three every couple days.
Mars is small in the telescope and getting a little dim. With Phoenix safely landed on his north pole and -- so far -- functioning well, you'll have lots of chances to point out mars in the sky to your friends. As summer rools by Mars will slowly fade and drift into twilight, becoming harder to pick out.
Saturn's rings are closing slowly. Since we first saw him earlier this year, they are definitely less tilted, obstructing less of the planet's globe. Cassini continues its explorations, with a two-year extension of its mission. It's hard to believe that the probe was circulating around Saturn for FOUR YEARS! It does seem like last month that we sat in the Hayden Planetarium for a live show of Cassini dropping the Huygens lander onto Titan.
I labeled a couple items near the Big Dipper. I waited until now to point them out because the Dipper is lower in the sky and a lot more comfortable and convenient to examine. When high overhead, it was a literal pain in the neck to bend back and look straight up.
The Hubble Deep field, 'HDF', remains a must-see, even tho other, better, deep space pictures were taken. No, you will not see any of the thousands of galaxies in the HDF image. When you explain the work of Hubble, in light of the delayed Shuttle flight to repair it, point to this spot as you show the drop-dead photo of those galaxies.
There's an other planetary star, pi-2 Ursae Majoris.(PIGH-2 URR-sigh ma-JAW-riss). It was announced in 2007 with these specs:
~See Table to the left~
Finding pi-2 is a bit tricky. I labeled stars that sit between it and the Dipper bowl as [A], [B], [C] on both the panorama and a detail chart. These are not the real names of the stars. The detail chart has their Bayer designations if you know the Greek alphabet.
Make SURE you hold the detail map so that the bowl stars line up with the stars in the sky. It should be rotated so the lower-left to upper-right diagonal is about horizontal. Miss this step and you will get very, very lost in space.
Step from Dubhe (DUH-bee) to star [A], confirm it by seeing star [B], move farther on to star [C]. Check each star by matching faint stras near them on both map and sky.
From star [C[ drift northeast a bit to a close group of so-so stars, labeled with the Greek letter pi on the map. Pi-2 is the southern of the group, closer to [C].
If you get dizzy, stop. take a breath and try again. Don't rush or run ahead among the stars. Step from star to star and get your bearings at each.
The next feature is a challenge, but it's feasible from the City.
It does take some patience and effort, so please be relaxed and calm. It also requires a really dark clear night. Test the night by looking inside the Dipper's bowl with your binoculars. Do you see all or most of the stars plotted on the detail chart? If not, you probably will have to pass up on the challenge for that night.
Sharpen the focus of your binoculars by inpsecting the stars in the Dipper area. Let the eyes relax; do not squint and stare. Adjust the binoculars only with the focus knob. Also, sit in a comfortable chair padded with pillows.
Keep nearby lamps off of your face by moving into shade or setting up jerry-rigged 'light breaks'.
We're hunting for two galaxies, M81 and M82, northwest of the Big Dipper's bowl. Their location is marked '81/82/ on the detail chart. The circle of sky within your glass about spans the distance between the front, west, stars in the bowl, Dubhe and Merak (MEH-rakk).
Run along the diagonal withn the bowl that ends on Dubhe. This is the more horizontal of the two possible diagonals. Continue on this line about its own length beoynd Dubhe. Take careful notice of star patterns aong the way and match them with the map. Chances ar pretty certain you'll come to star [D] without spotting anything special. At [D], stop and swim around it a bit.
Among the dimmest of the stars near [D] there may be one or two, that are a bit 'out of focus'. On some occasions you may see only one such misty dot.
You're looking at a pair of galacies 12 million light years away. That's to say, what we learn today about these two targets occurred 12,000,000 years ago, long before humans separated into a distinct species on Earth! The fellow to the north, to the right in the sky, is M82. The southern one, to the left, is M81. If you got an astronomy textbook or stargazing book, look up a picture of this pair.
What you see in the sky is nothing so snazzy as the observatory photograph. Never the less, you ARE seeing some very remote places in the cosmos thru a glass probably made for Yankee Stadium or Belmont.
M81 is a spiral galaxy much like our Milky Way and is a mite brighter and easier to discern. If you do see only one spot up there, it's M81 with M82 being too dim on the instant night. M82 is the 'exploding' galaxy in upheavel and disarray..
Ask yur telescope friend to show you these galaxies. They'll be a lot brighter in his instrument and may show definite tilt and shaps. Even so, you're seeing only the bright nuclear, part of the galaxies. It does require a large observatory telescope to capture their texture in a photograph.
Porrima (PO-rih-ma) is still with us in the evening sky of summer. Your astronomy friend is likely checking it from time to time to see when its two stars edge far enough apart to show up separately. For small scopes they are too close and blend into a single stellar dot. If you fail to get a clean view of Porrima as two discrete stars this year in evening, you will surely catch them next year. There after, the pair parts farther and farther until by end of the decade they are an easy target for just about any small telescope.
New York
Space Society
Chapter of the National Space Society