South Pole Telescope (SPT) — America’s New Planet X Tracker

Yowusa.com
Jacco van der Worp
Foreword by Marshall Masters

…Continued

The Internet is currently abuzz with interest for what is fondly called Planet X.  Whether Planet X is nothing but wild speculation or the subject of serious investigation, if you know what to look for, chances are you will find it.  The debate about whether it exists at all or not continues to rage.  Yet, most scientists in need of research funding will stay clear of going against accepted theory; when asked, they will proclaim the official dogma: "There is no such celestial body.  If there were, we would have observed it by now.  We have not; therefore, it cannot be there (Quod erat demonstrandum -- which was to be proven)."

Coming from the mouths of reputable astronomers, this usually kills any debate before it even starts.  Or perhaps it does not quite kill it totally; in spite of vehement denial by almost everybody connected to the astronomical society, the Planet X debate simply refuses to die off.  Better yet (or worse, depending on your point of view), it grows stronger almost day by day.

Thanks to the continuing stream of mission and project announcements that, on the surface, seem to defy logic altogether, this debate lives on.  We will look at one of these seemingly logic-defying projects in this article. 

We see a strong indication that something is afoot indeed, something quite big.

A Telescope on Antarctica

The above title should have raised at least your eyebrows if you keep up with the news and know a bit about international politics.  But it is true; a telescope, a rather large one at that, is under construction on Antarctica, which is the South Pole continent.  Most people would not want to be found dead on that barren, frigid world, and chances are you would end up frozen to death if you go there.  The continent is a cold and lifeless hell; it is no place for any human activity, for sure.

Nevertheless, the University of Chicago, together with those of Berkeley, Case Western Reserve and Illinois, and the Smithsonian Astrophysical Society are working on a project to build a telescope on Antarctica, at a stone’s throw from the geographical southernmost tip of the world.

Airborne Composites
Latest news, March 2006

This month Airborne Composites, The Netherlands, will complete the manufacturing of the Back up Structure for the South Pole Telescope (SPT) at their Ypenburg, The Hague premises.  Early 2005, Airborne was selected as contractor for the delivery of this 10 meter diameter carbon fiber dish by General Dynamics VertexRSI in San Jose, USA.

Each component is designed so that it can be broken into parts that will fit in an LC-130 aircraft, which can carry about 11 metric tons and has a maximum cargo bay width of 3 meters.  The installation window on the South Pole is only 2 months due to the severe weather conditions.  The SPT is planned to be ready for operation in 2007.

The ready-to-assemble parts are being built right now in places around the world and will soon be flown to Antarctica to be assembled on-site.

Moving South or Into Space

The project website states they want to look at Cosmic Microwave Background Radiation, in order to help determine the structure and age of the universe and to confirm whether the expansion of the universe is actually accelerating.

South Pole Telescope

A new 10 meter diameter telescope is being constructed for deployment at the NSF South Pole research station.  The telescope is designed for conducting large-area millimeter and sub-millimeter wave surveys of faint, low contrast emission, as required to map primary and secondary anisotropies in the cosmic microwave background.

Remarkable progress has been made in the characterization of the cosmic microwave background radiation (CMB) over the last several years.  It was nearly 30 years after the initial discovery of the CMB by Penzias and Wilson in 1965 before small differences in its intensity were measured by COBE and its spectrum was shown to be a blackbody to high precision.

Yet, this statement does not explain why the telescope needs to be in such a remote, inhospitable location as near the South Pole. 

Central Siberia offers equally dark night skies and a stable atmosphere too; it has almost equally cold winters, and it is much more easily accessible from the US and Europe, the origins of the construction parts of the telescope and the places the crews come from. 

When you take a look at the total cost in terms of money and effort of transport, construction and maintenance of a telescope on the South Pole, putting a similar telescope into a space orbit could well be cheaper than placing it on the South Pole.  One cannot help but think there is an additional reason to build it on Antarctica.  The US Senate must have found at least one, because funding for the construction and operation, while the process is anything but cheap, quietly passed the vote in both the Senate and the House of Representatives.

Most of the extra cost the operating crew will encounter on Antarctica will result from the extreme weather conditions there.  No matter how quiet and cold the weather may get, the atmosphere always shows some degree of activity, due to turbulence, density variation or pollution. 

All these factors influence an image obtained with the telescope and degrade the image, but it is possible to compensate for this degradation by using optical techniques.  A simple example is to take five pictures of a steady object in a noisy environment and average the pictures out.  The noise is random and will cancel out to nearly zero.  This will increase the signal to noise ratio of the resulting image, which leaves the image with much better contrast and quality.

In this particular case, a new technique will be employed called adaptive optics.  Adaptive optics will be used to compensate for the atmospheric disturbances to the image obtained from a ground-based telescope.  The adaptive optics for this telescope have been developed in a $20 million project that started at the end of the 1990’s, a project in which 27 partner institutions have joined.  A major role in this development went to the University of Chicago. 

University of Chicago, 12 August, 1999
University will play major role
in Adaptive Optics Center

The University will play a key role as one of UCSC’s 27 partner institutions through the Chicago Adaptive Optics System Laboratory, which will be led by Edward Kibblewhite, Professor in Astronomy & Astrophysics, and in related Midwestern education and outreach through the Space Explorers Program, led by Randall Landsberg, Director of Education and Outreach for the University’s Center for Astrophysical Research in Antarctica.

Adaptive optics will enable ground-based telescopes to resolve objects 10 times smaller than is possible today, Kibblewhite said.  Earth’s atmosphere distorts light from stars and galaxies in much the same way shimmering heat from a road distorts distant objects.  This distortion has limited the resolution attained by astronomers for the last 300 years.

But adaptive optics techniques can remove the effect, permitting astronomers to observe everything from the weather on Neptune to exploding stars at the most distant reaches of the universe.  The technique has more earthly applications as well.

Kibblewhite began developing such a laser in 1989 with $4.8 million in NSF grants.  He plans to install the laser next year on the 3.5-meter telescope at Apache Point Observatory in New Mexico.  The system would give the telescope the same resolution in infrared wavelengths as the Hubble Space Telescope, he said.

As part of the Center for Adaptive Optics, Kibblewhite will attempt to develop a versatile laser for use by any observatory.  He also will attempt to develop the mathematical techniques needed to use adaptive optics on visible-light telescopes and for wider fields of view.

The last few sentences certainly raised some eyebrows.  Development of the adaptive optics technique centers on both the infrared and the visible light wavelength range.  These are interesting ranges of observation if you are looking for something specific.

The need for these adaptive optical techniques in the meantime does increase the cost of using this telescope considerably; again, the question of why governments are putting the telescope on Antarctica rather than into orbit jumps up into our faces.

A Race against Time

We must consider the limits placed on human activity on Antarctica as well.  The white continent must remain as pristine as possible; international treaty only allows small-scale scientific research at the "bottom of the world.”  A larger telescope, especially with dozens of building, maintenance and operating crew members stationed there on a semi-permanent basis to assemble and run it, will more or less upset the ecology and break the treaty.  The strangest aspect to all of this has to be the short amount of time from the start of this project until expected completion.

The construction of the telescope started in November 2004.  This telescope is planned to be in operation in 2007.  It has to be delivered in parts and sections by a fleet of C-130 cargo aircraft and assembled on-site with only approximately a two-month per year window of opportunity in the harsh weather to safely construct and install all of the components.  What is the hurry with this project?  What is so compelling in the sky above the South Pole that anyone would need to rush to see it?  Why this murderous schedule of a total of six months of construction to assemble a fairly large telescope?  Is there a deeper goal to this project?

A closer look at the project web page might shed some light on that.  The South Pole Telescope construction started in November of 2004.  Its goal, as stated above, is to observe space in the sub-millimeter range.  At first, it doesn't look like anything spectacular, but taking a closer look, it appears that this will be an infrared telescope mainly.

Infrared Astronomy

Infrared Astronomy is the discipline of astronomy studying the skies for wavelengths that range from 1 micron (one millionth of a meter) to 1 millimeter (one thousandth of a meter).  The shortest wavelength in the infrared band is just beyond visible light.  Red laser light from a ruby laser has a wavelength of 694.3 nanometers or 0.69 micron.  From 1 micron to just above 1 micron is called near-infrared; the 10-100+ micron range is called far infrared.  Humans can't see infrared radiation, but we can feel it.