Venus on the Horizon

1999-06-19

Venus can appear as a brilliant evening star. Besides the sun and moon, Venus is the brightest object visible in Earth's sky. Because it is closer to the sun than Earth, Venus never strays far from the sun in its apparent position and is seen ...

Tharsis Volcanos

1999-06-18

Ice crystal clouds float above the immense Tharsis volcanos of Mars in this recently released picture from NASA's Mars Global Surveyor spacecraft. Olympus Mons at the upper left is 340 miles across and almost 15 miles high - the largest volcano ...

NGC 4565: Needle Galaxy

1999-06-17 William McLaughlin

Presenting a sleek needle-like profile the magnificent spiral galaxy NGC 4565 is viewed edge-on from planet Earth. Its core of stars bulges from the centre of a thin disk of spiral arms and dust. The core appears to be cut sharply by dust lanes ...

Sprite Fireworks

1999-06-16

Sometimes lightning occurs out near space. One such lightning type is the recently documented red sprite lightning, which has only been photographed and studied on Earth over the last few years. The origins of all types of lightning remains ...

The Sun Oscillates

1999-06-15

Our Sun is in a continual state of oscillation. Large patches of the Sun vibrate in and out, back and forth, even as the Sun rotates. One mode of Solar oscillation is depicted graphically above, with blue indicating outward motion, and red ...

N159 and the Papillon Nebula

1999-06-14

In a search for massive stars, the Hubble Space Telescope has peered into yet another spectacular region of star formation. This nebula, known as N159, spans over 150 light-years and is located in the neighboring Large Magellanic Cloud galaxy, ...

Zodiacal Light

1999-06-13 AAO

Sometimes the sky itself seems to glow. Usually, this means you are seeing a cloud reflecting sunlight or moonlight. If the glow appears as a faint band of light running across the whole sky, you are probably seeing the combined light from the ...

Venus: Just Passing By

1999-06-12

Venus, the second closest planet to the Sun, is a popular way-point for spacecraft headed for the gas giant planets in the outer reaches of the solar system. Why visit Venus first? Using a " gravity assist " maneuver, spacecraft can swing by ...

AB Aurigae: How To Make Planets

1999-06-11

This enhanced Hubble Space Telescope image shows in remarkable detail the inner portion of the disk of dust and gas surrounding the star AB Aurigae. Knots of material, visible here for the first time, may well represent an early stage of a ...

Mj?lnir: Impact Crater

1999-06-10

The stark surface of Earth's moon is pocked with large craters, records of a history of fierce bombardment by the solar system's formative debris. It may be difficult to imagine, but nearby planet Earth itself has endured a similar cosmic ...