Arecibo: The Largest Telescope
9.03.1996

The Arecibo radio telescope is currently the largest single-dish telescope in the world. First opening in 1963, this 305 meter (1000 foot) radio telescope resides in a natural valley of Puerto Rico. The Arecibo...

Vega
15.07.1997

Vega is a bright blue star 25 light years away. Vega is the brightest star in the Summer Triangle, a group of stars easily visible summer evenings in the northern hemisphere. The name Vega...

Methane Rain Possible on Titan
2.08.2006

Might it rain cold methane on Saturn's Titan? Recent analyses of measurements taken by the Huygen's probe that landed on Titan in 2005 January indicate that the atmosphere is actually saturated with methane at a height of about 8 kilometers.

Planets Around Sun-Like Stars
31.01.1996

Do many Sun-like stars have planets? Speculation on this point has been ongoing since humanity's realization that other stars existed. Only in the past year, however, have answers and discoveries been realized. The above plot summarizes the four known cases of normal stars having planets.

The Millennium that Defines Universe
1.01.2000

Welcome to the millennial year at the threshold of millennium three. During millennium two, humanity continually redefined its concept of "Universe": first as spheres centered on the Earth, in mid-millennium as the Solar System, a few centuries ago as the Galaxy, and within the last century as the matter emanating from the Big Bang.

Jets from the Necklace Nebula
18.05.2021

What celestial body wears the Necklace Nebula? First, analyses indicate that the Necklace is a planetary nebula, a gas cloud emitted by a star toward the end of its life. Also, what appears to be diamonds in the Necklace are actually bright knots of glowing gas.

APOD: 2024 August 7 Б Milky Way Behind Three Merlons
7.08.2024

To some, they look like battlements, here protecting us against the center of the Milky Way. The Three Merlons, also called the Three Peaks of Lavaredo, stand tall today because they are made of dense dolomite rock which has better resisted erosion than surrounding softer rock.

Spherical Planetary Nebula Abell 39
28.07.2005

Ghostly in appearance, Abell 39 is a remarkably simple, spherical nebula about five light-years across. Well within our own Milky Way galaxy, the cosmic sphere is roughly 7,000 light-years distant toward the constellation Hercules.

Venus: Earth's Sister Planet
15.08.1995

This picture in visible light was taken by the Galileo spacecraft. Venus is very similar to Earth in size and mass - and so is sometimes referred to as Earth's sister planet - but Venus has a quite different climate.

A Quintet of Galaxies
15.11.1995

Five closely grouped galaxies are visible in this image made using the Kitt Peak National Observatory 2.1 meter telescope. The grouping is commonly known as Stephan's Quintet. Four of the galaxies show essentially the same redshift suggesting that they are at the same distance from us.