Planets and Stars under the Magnifying Glass

Hazi, A U

关键词: GLASS;    MILKY WAY;    NIGHT SKY;    NONLUMINOUS MATTER;    PLANETS;    SOLAR SYSTEM;    SOUTHERN HEMISPHERE;    STARS;    SUN;    TELESCOPES;    UNIVERSE;    WAVELENGTHS;   

DOI  :  10.2172/907853
RP-ID  :  UCRL-TR-228150
PID  :  OSTI ID: 907853
Others  :  TRN: US200721%%552

学科分类：社会科学、人文和艺术（综合）

美国|英语

来源: SciTech Connect

【 摘 要 】

Looking out to the vastness of the night sky, stargazers often ponder questions about the universe, many wondering if planets like ours can be found somewhere out there. But teasing out the details in astronomical data that point to a possible Earth-like planet is exceedingly difficult. To find an extrasolar planet--a planet that circles a star other than the Sun--astrophysicists have in the past searched for Doppler shifts, changes in the wavelength emitted by an object because of its motion. When an astronomical object moves toward an observer on Earth, the light it emits becomes higher in frequency and shifts to the blue end of the spectrum. When the object moves away from the observer, its light becomes lower in frequency and shifts to the red end. By measuring these changes in wavelength, astrophysicists can precisely calculate how quickly objects are moving toward or away from Earth. When a giant planet orbits a star, the planet's gravitational pull on the star produces a small (meters-per-second) back-and-forth Doppler shift in the star's light. Using the Doppler-shift technique, astrophysicists have identified 179 planets within the Milky Way galaxy. However, most of these are giant gas planets, similar in size to Jupiter and Saturn, and they orbit parent stars that are much closer to them than the Sun is to Earth. Planets similar in size to Earth have also been found, but they, too, are so close to their suns that they would be much hotter than Earth and too hot for life to exist. In 2005, an international collaboration of astronomers working with telescope networks throughout the Southern Hemisphere uncovered clues to a small, rocky or icy planet similar to Earth. The new planet, designated ogLE-2005-BLg-290-Lb, is the farthest planet from our solar system detected to date. The discovery was made by the Probing Lensing Anomalies network (PLAnET) using microlensing--a technique developed nearly two decades ago by Livermore astrophysicists as part of the Massively Compact Halo object (MACHo) Project, which searched for evidence of dark matter.