Background radiation (cosmic)—

The radiation left over from the Big Bang explosion at the beginning of the universe. As the universe expanded, the temperature of the fireball cooled to its present level of 2.7 degrees above absolute zero.

Brown Dwarf—

A star-like object that contains less than about 0.08 the mass of the Sun and is thus too small to ignite nuclear fuels and become a normal star. Brown dwarfs emit small amounts of infrared radiation due to the slow release of gravitational energy.

Dark energy—

An as yet unknown form of energy that pervades the universe. Its presence was inferred from the discovery that the expansion of the universe is accelerating, and these observations suggest that about 70 percent of the total density of matter plus energy is in this form. One explanation for dark energy is Einstein’s cosmological constant.

Flat universe—

Cosmological concept that states that the universe will expand forever at a decelerating rate, and will never pass an outer limit.

Gamma-ray bursts—

A sudden burst of gamma rays coming from a source usually in deep space. The burst may last from a fraction of a second to several minutes.

Gravitational microlensing—

Gravitational lensing due to a stellar mass object. This lensing phenomenon is termed “microlensing” because the mass of the lens is so small compared with that of a galaxy.

Microlensing of distant stars by intervening faint stars can reveal planets in orbit around the lensing star.

Interferometry—

The main technique used by astronomers to map sources at high resolution and to measure their positions with high precision.

Kuiper Belt objects (KBOs)—

Icy planetesimals distributed in a roughly circular disk in the outer regions of our solar system, 50 to 100 AU from the Sun.

Redshift—

Radiation from an approaching object is shifted to higher frequencies (to the blue), while radiation from a receding object is shifted to lower frequencies (to the red). A similar effect raises the pitch of an ambulance siren as it approaches. The expansion of the universe makes objects recede so that the light from distant galaxies is redshifted. The redshift is often denoted by z, where z=v/c and v is the velocity and c the speed of light.

AAPB

Astronomy and Astrophysics Planning Board

AASC

NRC Astronomy and Astrophysics Survey Committee

ACAST

Advisory Committee for AST (NSF Astronomical Sciences Division)

ACCORD

AURA Coordinating Council of Observatory Research Directors

ALMA

Atacama Large Millimeter Array

ARISE

Advanced Radio Interferometry between Space and Earth

AST

Advanced Solar Telescope (now called the Advanced Technology Solar Telescope, or ATST); NSF Astronomical Sciences Division

ATM

NSF Division of Atmospheric Sciences

AURA

Associated Universities for Research in Astronomy, Inc.

CAA

NRC Committee on Astronomy and Astrophysics

CARMA

Combined Array for Research in Millimeter-wave Astronomy

CGRO

Compton Gamma-Ray Observatory

COMRAA

Committee on the Organization and Management of Research in Astronomy and Astrophysics

DOE

U.S. Department of Energy

EVLA

Expanded Very Large Array

EXIST

Energetic X-ray Imaging Survey Telescope

FASR

Frequency Agile Solar Radio telescope

GBT

Green Bank Telescope (now named after Senator Robert C. Byrd)

GLAST

Gamma-ray Large Area Space Telescope

GSMT

Giant Segmented Mirror Telescope

HENP

DOE Office of High Energy and Nuclear Physics

HEP

DOE Division of High Energy Physics

HEPAP

High Energy Physics Advisory Panel

HST

Hubble Space Telescope

LIGO

Laser Interferometer Gravitational-Wave Observatory

LISA

Laser Interferometer Space Antenna

LSST

Large-aperture Synoptic Survey Telescope

MPS

NSF Mathematical and Physical Sciences Directorate

MPSAC

MPS Advisory Committee

MRE

NSF Major Research Equipment line

NASA

National Aeronautics and Space Administration

NGST

Next Generation Space Telescope

NOAO

National Optical Astronomy Observatory

NRAO

National Radio Astronomy Observatory

NRC

National Research Council

NRL

Naval Research Laboratory

NSAC

Nuclear Science Advisory Committee

NSF

National Science Foundation

NSO

National Solar Observatory

NVO

National Virtual Observatory

OMA

NSF Office of Multidisciplinary Affairs

OMB

Office of Management and Budget

OPP

NSF Office of Polar Programs

OSS

NASA Office of Space Science

OSTP

Office of Science and Technology Policy

ROTSE

Robotic Optical Transient Search Experiment

SAFIR

Single Aperture Far Infrared observatory

SAGENAP

Science Assessment Group for Experiments in Non-Accelerator Physics

SDO

Solar Dynamics Observatory

SKA

Square Kilometer Array

SPST

South Pole Submillimeter-wave Telescope

SSB

NRC Space Studies Board

SScAC

NASA Space Science Advisory Committee

TPF

Terrestrial Planet Finder

TSIP

NSF Telescope System Instrumentation Program

VERITAS

Very Energetic Radiation Imaging Telescope Array System

VLA

Very Large Array