Globular cluster
Pal 4
Globular cluster
A globular cluster of hundreds of thousands of old stars orbiting in the Galaxy’s halo: among the oldest objects of the Milky Way, about 12 billion years old. Its metal abundance is 3.9 % of the Sun’s. Distance, brightness and structure come from the Harris catalogue.
| Type | Globular cluster |
|---|---|
| Constellation | Ursa Major |
| Distance | 108,700 pc (354.5 thousand ly) |
| Metallicity [Fe/H] | -1.41 |
| Half-light radius | 16.1 pc |
| Central concentration (c) | 0.93 |
| Radial velocity | 74.5 km/s |
| Source | Harris 1996 (2010) |
| Right ascension (J2000) | 11h 29m 16.8s |
| Declination (J2000) | +28° 58′ 25″ |
In the sky
Visible from the whole Northern Hemisphere and south to latitude 61° S. North of latitude 61° N it never sets. It stands highest at midnight in March, the best time to observe it.
Through a telescope from Earth
Light's journey
The light you see tonight set out 355 thousand years ago. At that time our ancestors were using stone tools; Homo sapiens did not exist yet. At the speed of Voyager 1, the fastest craft leaving the Solar System (16.9 km per second), the trip would take 6.3 billion years.