An Updated Very Long Baseline Array (of Linked Radio Telescopes) Is Back in the News — Farthest Distance Yet Calculated with Reportedly Only a 9 Percent Error

© 2011 Peter Free

 

24 February 2011

 

 

Improvements increase the reach of one of science’s slightly older toys

 

The Very Long Baseline Array is a group of 10 radio telescopes scattered across 8,611 kilometers (5,351 miles) from the St. Croix (U.S. Virgin Islands) to Mauna Kea, Hawaii.

 

The in-between locations include Hancock, New Hampshire; North Liberty, Iowa; Fort Davis, Texas; Los Alamos and Pie Town, New Mexico; Kitt Peak, Arizona; Brewster, Washington; and Owens Valley, California.

 

The Array’s super-cooled telescopes receive longer than infrared long-wavelength light.  It began operation in 1993.  New receivers and a supercomputer were installed in 2010.

 

The VLBA provides the greatest ability to see fine detail, called resolving power, of any telescope in the world. It can produce images hundreds of times more detailed than those from the Hubble Space Telescope . . . .

 

With improvements now nearing completion, the VLBA will be as much as 5,000 times more powerful as a scientific tool than the original VLBA of 1993.

 

© Public Information Office, Super-Sharp Radio 'Eye' Remeasuring the Universe, National Radio Astronomy Observatory (19 February 2011) (italics added)

 

 

But — how does one quantify the comparative “power of a scientific tool,” or loosely sling the phrase, “hundreds of times more detailed,” around, without losing a bit of semantic credibility?

 

I suspect the National Radio Astronomy Observatory’s public information office got carried away with its excitement.

 

 

The VLBA did something pretty impressive

 

New measurements with the VLBA have placed a galaxy called NGC 6264 at a distance of 450 million light-years from Earth, with an uncertainty of no more than 9 percent. This is the farthest distance ever directly measured, surpassing a measurement of 160 million light-years to another galaxy in 2009.

 

© Public Information Office, Super-Sharp Radio 'Eye' Remeasuring the Universe, National Radio Astronomy Observatory (19 February 2011)

 

That light began traveling toward us roughly when the Ordovician geologic period was ending.

 

Under the circumstances, a 9 percent error range is notably small.  But I have doubts about how accurate that estimate of error can be, given the fact that the Array is pushing into unknown territory in establishing the distance in the first place.  It is pretty hard to be sure about distance, until you’ve at least figuratively paced it off with inarguable means.

 

 

Closer to home — the VLBA is also used to measure changes in the Earth’s crust

 

Using quasars’ positions as set, the Array can track fractions of an inch changes in the positions of its telescopes relative to each other.  That precision is helpful in seismology, geology, and assessing Global Positioning System accuracy.

 

 

The moral? — Updating old tools sometimes works, but budget cuts may threaten staying up to date

 

In science, a lot of interesting happenings don’t make it into mainstream consciousness.

 

That forecasts difficult times for scientific endeavors under government budget cuts.