Pulsar
Hulse–Taylor Binary (PSR B1913+16)
The first evidence for gravitational waves — 1993 Nobel Prize
The first double neutron star, found by Hulse and Taylor with Arecibo in 1974: a 59 ms pulsar orbits an unseen neutron star every 7.75 hours on an orbit slightly larger than the Sun's diameter. The orbit shrinks by 3.5 m a year, exactly as general relativity's prediction of gravitational waves requires; they will merge in ~300 million years.
| Type | Pulsar |
|---|---|
| Constellation | Aquila |
| Period | 59.03 ms |
| Orbital period | 7.75 hours |
| Eccentricity | 0,617 |
| Masses | 1,440 + 1,389 M☉ |
| Periastron advance | 4.2°/year |
| Orbital decay | 3.5 m/year |
| Merger | in ~300 million years |
| Distance | ~5 kpc (uncertain) |
| Discovery | 1974, Hulse & Taylor (Arecibo) |
| Right ascension (J2000) | 19h 15m 28.1s |
| Declination (J2000) | +16° 06′ 27″ |
In the sky
Visible from the whole Northern Hemisphere and south to latitude 74° S. North of latitude 74° N it never sets. It stands highest at midnight in July, the best time to observe it.
Through a telescope from Earth
Light's journey
The light you see tonight set out 17 thousand years ago. At that time Homo sapiens was spreading out of Africa; there was no farming yet. At the speed of Voyager 1, the fastest craft leaving the Solar System (16.9 km per second), the trip would take 304 million years.