Tycho Brahe Measures the Sky
30.05.1999

Tycho Brahe was the most meticulous astronomical observer of his time. Brahe, who lived between 1546 and 1601, set out to solve the day's most pressing astronomical problem: to determine whether the Earth or the Sun was at the center of the Solar System.

Tycho Brahe Measures the Sky
7.01.2001

Tycho Brahe was the most meticulous astronomical observer of his time. Brahe, who lived between 1546 and 1601, set out to solve the day's most pressing astronomical problem: to determine whether the Earth or the Sun was at the center of the Solar System.

HD 10180: Richest Yet Planetary System Discovered
25.08.2010

Do other rich planetary systems exist? Our Solar System has the most planets of any known star, most probably because it is so hard to detect planets around other stars. Sensitive measurements, though, have...

The X-ray Timing Explorer
3.01.1996

Launched Saturday on a Delta rocket, the X-ray Timing Explorer (XTE) will watch the sky for rapid changes in X-rays. XTE carries three separate X-ray telescopes. The Proportional Counter Array (PCA) and the High Energy X-ray Timing Experiment (HEXTE) will provide the best timing information in the widest X-ray energy range yet available.

APOD: 2025 April 15 Б Planetary Nebula NGC 1514 from Webb
15.04.2025

What happens when a star runs out of nuclear fuel? For stars like our Sun, the center condenses into a white dwarf while the outer atmosphere is expelled into space to appear as a planetary nebula.

Worlds of a Distant Sun: 47 Ursae Majoris b
1.07.1996

Within the last few years, observational astronomy has given humanity evidence of the existence of worlds beyond the solar system. Indeed, solar-type stars are now inferred to harbor planets of approximately Jupiter mass - some residing in temperature zones which could conceivably support liquid water and therefore life!

A Dangerous Summer on HD 80606b
4.02.2009

On the distant planet HD 80606b, summers might be dangerous. Hypothetic life forms floating in HD 080606b's atmosphere or lurking on one of its (presently hypothetical) moons might fear the 1,500 Kelvin summer heat, which is hot enough not only to melt lead but also nickel.

HH 222: The Waterfall Nebula
24.10.2011

What created the Waterfall Nebula? No one knows. The structure seen in the region of NGC 1999 in the Great Orion Molecular Cloud complex is one of the more mysterious structures yet found on the sky. Designated HH-222, the elongated gaseous stream stretches about ten light years and emits an unusual array of colors.

A Close Encounter Of The Stellar Kind
11.12.1999

The unassuming star centered in this sky view will one day be our next door stellar neighbor. The faint 9th magnitude red dwarf, currently 63 light-years away in the constellation Ophiucus, was recently discovered to be approaching our Solar System.

A Close Encounter of the Stellar Kind
26.06.1997

The unassuming star centered in this sky view will one day be our next door stellar neighbor. The faint 9th magnitude red dwarf currently 63 light-years away in the constellation Ophiucus was recently discovered to be on a course toward our Solar System.