Press Release

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

By SpaceRef Editor
February 21, 2002
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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, 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

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

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.


Dr. Guenther Eichhorn

Harvard-Smithsonian Center for Astrophysics

Phone: 617-495-7260

David A. Aguilar, Director of Public Affairs

Harvard-Smithsonian Center for Astrophysics

Phone: 617-495-7462 Fax: 617-495-7468

SpaceRef staff editor.