David Aguilar
(617) 495-7462

Christine Pulliam
(617) 495-7463


CfA Press Release
 Release No.: 02-05
For Immediate Release: February 21, 2002

Physicists Gain Online Research Tool That Will Save Thousands of Hours Yearly

Cambridge, MA - In 1939, an article titled "The Mechanism of Nuclear Fission" opened the doors of knowledge that would lead to the atomic bomb. In 1948, "The Origin of Chemical Elements" revealed how the opposite physical process, nuclear fusion, powers stars. Until now, there has been no easy way to find these and other seminal scientific papers that laid the foundations of modern physics. But now, physicists and astronomers alike can have quick, free access to the knowledge of the past 100 years of physics research.

That access is available through the NASA Astrophysics Data System or ADS (online at http://adswww.harvard.edu/), the largest non-commercial database of scientific abstracts and articles in the world. Since its debut in 1993, the ADS has grown in popularity so much that it now draws more than 50,000 users per month, 10,000 of whom use the ADS at least 10 times per month.

"With the new physics material we've added to the ADS, the usefulness of this database for both physicists and astronomers has been substantially increased," said Dr. Guenther Eichhorn, ADS Project Scientist. "We will be working to advertise the new capabilities of the ADS in the physics community, where researchers have previously had to rely on expensive commercial services to access past articles."

The Astrophysics Data System

The ADS provides two key resources to researchers searching for previously published works. The first is an abstract database, which now holds more than 2.8 million abstracts from more than 200 journals.

As its second resource, the ADS includes the full text of many articles in the form of scanned pages. More than 1.8 million pages from some 250,000 articles occupy 400 gigabytes of memory in this database. Approximately 5,000 additional pages are added every week.

The ADS covers all major and most minor astronomical journals back to volume 1, the first issue published. This includes articles printed as far back as 1827. More than 95% of the astronomical literature from 1975 or later is included in the ADS. Placing these materials online provides an enormous time saver to the research community. "We estimate that the ADS saves researchers more than 800,000 hours per year that they would otherwise spend in the library painstakingly copying page after page of journal articles," stated Eichhorn. "That's the equivalent of 400 full-time employees."

Physics Is Added

The latest additions to the ADS database are the fruit of a collaboration between the ADS and the American Physical Society, which publishes nearly a dozen physics journals. In this agreement, the society provided the ADS with more than 300,000 abstracts from nine journals, including Physical Review A through E and Physical Review Letters. The ADS also received comprehensive lists of references from those journals. In addition, the ADS now links to the society's database of online articles, making another large set of scanned articles directly accessible to ADS users. Access to these APS articles is available to members of institutions with a subscription to APS journals and on a per-article purchase basis to others.

In return, the American Physical Society will link to the ADS astronomy records from their reference lists. This will allow physics researchers to easily access detailed information for astronomy or astrophysics articles referenced from the society's physics publications.

The Future of the ADS

Eichhorn and the ADS team foresee a future of continued growth and increasing access to their extensive database. A high priority for the coming years is improving the ability of third-world nations to access the ADS.

Already, 10 mirror sites are operating worldwide in nations as diverse as Brazil, China and India. This speeds access to the ADS information for researchers in other countries.

However, many developing countries still lack easy internet access. For these countries, the ADS team is working to design portable, self-contained systems that can store the full ADS database.

"All of the abstracts in the ADS already can fit onto a typical laptop computer," said Eichhorn. "However, the scanned articles require much more space."

With the steadily increasing storage space available on computer hard disks, Eichhorn believes that a stand-alone PC system can be developed within the next year that will be able to store lower-resolution scans of all the articles in the ADS.

"A lot of people would benefit greatly from a system like this," he added.

Eichhorn will travel to a United Nations workshop in Argentina this September to present the ADS plans for expanding third-world access.

Headquartered in Cambridge, Massachusetts, the Harvard-Smithsonian Center for Astrophysics (CfA) is a joint collaboration between the Smithsonian Astrophysical Observatory and the Harvard College Observatory. CfA scientists organized into seven research divisions study the origin, evolution, and ultimate fate of the universe.

For more information, contact:

David A. Aguilar
Director of Public Affairs
Harvard-Smithsonian Center for Astrophysics

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