A black hole forms when gravity overcomes all other known forces. It then collapses to an infinitesimally small size. Although there is some physical size associated with a black hole, it is difficult to say what that size actually is. So, formally, a black hole has no size.
In fact, a black hole has only three physical principles: mass, spin, and electric charge. Only one of these, mass, can be measured confidently. The orbit of a star can be used to determine how much mass is inside its orbit. Scientists prove the existence of a black hole by showing that there is a lot of mass inside a small volume, as determined by the radii of the orbits of neighboring stars.
To measure the mass of the black hole at the center of the Milky Way Galaxy, scientists needed to be able to see the stars as close as possible to the center of the Galaxy. By tracking specific stars orbiting the proposed black hole from 1995 through 2006, Dr. Andrea Ghez provided evidence which established the existence of Sgr A*, a supermassive black hole at the Galactic Center. Dr. Ghez and her team have now established that Sgr A* has a mass 4 million times the mass of the Sun.
“Earth’s atmosphere has air currents similar to those that you see rising from a boiling pot of water or as steam rising from hot pavement at midday. These air currents are constantly rolling, disturbing the incoming light from stars. Keck Observatory has perfected a system for compensating for atmospheric turbulence, by measuring incoming starlight thousands of times per second to correct for distortions. I have watched as the Adaptive Optics system at Keck Observatory has evolved over the past 10 years, and it is truly a miracle how well this system works.” Dr. Mike Liu, Chair of the Keck Observatory Adaptive Optics (AO) Working Group and Professor of Astronomy at the University of Hawai`i
With its Laser Guide Star Adaptive Optics (LGSAO) system, Keck Observatory has firmly positioned itself as the world leader in adaptive optics astronomy. The Observatory leadership is committed to an ambitious new technology program designed to maintain Keck’s leadership role in adaptive optics for years to come. The Observatory will install a robust new laser on the Keck I Telescope before the end of 2008, and plans for a revolutionary Next Generation Adaptive Optics system, consisting of multiple laser beams, are in the design phase.
“Having Laser Guide Star Adaptive Optics on both telescopes strongly enhances the discovery potential of our observatory,” says Keck Observatory Director Taft Armandroff. “Not only does the new laser provide an additional resource on the Keck I Telescope, but it also allows for significant improvements in performance and technological innovation,” explains Armandroff.
The Keck I laser was funded in part by a grant from the National Science Foundation, and it will provide a low-power pinpoint of light that can be projected 90 kilometers up into the Earth’s atmosphere to create an artificial bright star, called a laser guide star. Keck astronomers use this laser guide star to take measurements high enough up in the atmosphere to compensate for distortions, and these measurements provide the basis for their adaptive optics corrections. The Keck I laser will improve upon the existing Keck II laser, which has been in operation since 1999, in several ways. Among its advantages, the new laser will be:
The Keck I laser will double the existing LGSAO capacity of the Observatory making this highly sought after technology more available. Additional funding is being sought from private philanthropy to pay for the installation and commissioning of the new Keck I LGSAO facility. Click the learn more to continue reading about this major technical innovation in ground-based astronomy.
What is the value of a night observing on the Keck Telescopes? Dr. Paul Butler, an astronomer at the Carnegie Institution of Washington in Washington, D.C, admits that he recently turned down an invitation to the White House in order to spend the night observing at Keck Observatory. Time on the Keck Telescopes is highly prized, and the process to earn half a night, a full night, or a few nights of Keck Telescope time is extremely competitive.
The University of California and the California Institute of Technology, Keck’s partner institutions, are each allocated roughly one-third of the available nights. The remaining one-third of the nights is divided amongst NASA, the University of Hawai`i (the land manager of the Mauna Kea Science Reserve), the Observatory Director, internal engineering and maintenance, and the National Optical Astronomy Observatory’s (NOAO) Telescope System Instrumentation Program (TSIP). Through TSIP, NOAO investments in new instrumentation for Keck Observatory are traded for a specified number of observing nights. The pool of potential observers is clearly much larger than the time available.
The Observatory strives to ensure that the process of allocating time maximizes the scientific productivity of the world’s largest telescopes. The telescope schedules are produced twice a year through a careful series of steps overseen by Keck’s Observing Support Coordinator, Barbara Schaefer. The telescope schedules are not computer-generated, but rather finely tweaked by hand, by Schaefer. It is fair to say that the Observatory’s scheduling system works, since the scientific output of Keck Observatory is unparalleled in the world today. Read more about the process the Observatory uses to allocate time on the Keck Telescopes, as explained by Keck’s scheduling guru Barbara Schaefer, by clicking the Learn More button.
Profile of Dr. Jerry Nelson
“As long as I can recall I have loved looking at the heavens and pondering the enormity of the universe.” - Jerry Nelson, principal designer of the Keck Telescopes and professor of astronomy at the University of California (UC) at Santa Cruz
As a young man, Jerry Nelson had an affinity for math and science. Nelson studied physics as an undergraduate at Caltech, where he dabbled in astronomy. Richard Feynman taught the freshman and sophomore physics class at Caltech during Nelson’s undergraduate career. “Feynman’s dynamic style and approach to physics excited me,” says Nelson. “As a result of his class, I realized that I could understand physics at a very tangible physical level, not just in terms of mathematics.” Nelson also worked with Gerry Neugebauer and Bob Leighton as an undergraduate and was deeply impressed by the cleverness these mentors employed in designing and building apparatus, and also by their critical attention to details. He went on to graduate school in Physics at UC Berkeley.
After graduating, Nelson worked in astrophysics as a research fellow at Lawrence Berkeley National Laboratory (LBNL). His work was heavily oriented towards unusual instrumentation and electronics. In early 1977 a group of UC astronomers formed a committee to explore the possibilities for future telescopes for UC. Because of his instrumentation experience Nelson was asked to join this group. “This was the opportunity of a lifetime. Of course, I said yes,” he recalls. The group considered various possibilities, ranging from a new 3-meter telescope at a darker site (UC had a 3-meter telescope on Mount Hamilton above San Jose, but it was suffering from increasing light pollution), to a larger telescope like others that had recently been built.
After some discussion, Nelson committed to think about the possibilities of building a larger telescope. Some months later he suggested that a 10-meter telescope was possible and that it should be a segmented mirror telescope in order to make it technically practical. This was the beginning of the story of the Keck Telescopes. Nelson shares his thoughts on the challenges of designing the Keck Telescopes in this short video clip (requires Flash player).
Click the Learn More button below to read more about Jerry Nelson’s pivotal role in designing the Keck Telescopes.
“One of the Advancement Office’s first priorities was to begin building an identity for Keck that was visually appealing and representative of the uniqueness of the twin 10-meter telescopes. We retained Creative Communications, a local design firm in Waikoloa, to design our Keck Observatory logo in mid-2005. The hexagons represent the number of segments on the primary mirrors as well as its design.”
-Debbie Goodwin, Director of Advancement, W. M. Keck Observatory
Most non-profits depend on diverse sources of revenue to support their mission. The Keck Boutique is a way for the Observatory to bring attention to its prominence in world astronomy - and simultaneously contribute to the organization’s purpose. The Boutique offers a distinctive line of gifts and apparel, including logo-wear caps, beanies, golf gadgets, wine glasses, coffee mugs, canvas bags, postcards, Frisbee discs, letter openers, polo shirts, t-shirts, sweatshirts, women’s shirts, and youth t-shirts. Non-logo items include the “What’s Up in the Universe?” DVD, a Keck Telescope model kit (be forewarned that this is a very challenging activity for even the most technical or engineering minded), and the Keck Star Globe.
“Most everyone who gets an insider’s glimpse of the Observatory ends up purchasing a KeckWear souvenir,” Goodwin explains.“We hope our merchandise inspires people to get more involved in this amazing era of discoveries about our universe,” she says.
Larry Bryan, a regular attendee at Keck Observatory public lectures, graciously volunteered his time and expertise to create an online store of Keck merchandise. Preview items in the Observatory’s virtual store and purchase items by calling 808.881.3854. The Headquarters Store is located in the Advancement Office, and it is open Monday through Friday from 9 am to 4 pm.
KeckWear will be taking its first cosmic journey this March, when astronauts Rick Linnehan and Japan Aerospace Exploration Agency’s Takao Doi will be wearing KeckWear short sleeve polo shirts during Space Shuttle Mission STS-123, scheduled to launch on March 13, 2008. Be on the lookout for photos of KeckWear in space in an upcoming issue of Cosmic Matters.