Tempel 1
What is Tempel 1?
Comets· Nucleus ~6 km. The first comet humanity deliberately hit. In 2005 NASA's Deep Impact fired a 370-kg impactor into the nucleus at 37,000 km/h, blasting out ice and dust, and Stardust returned in 2011 to inspect the crater. See its 5.6-year orbit in the orbit view.
The orbit of Tempel 1 at this moment: https://nowsky.org/solar/orbit?fw=tempel1&sp=10 — replayed live, no login.
Orbit and period
| Nucleus | 7.6 × 4.9 km |
|---|---|
| Period | 5.58 yr |
| Distance | 1.54~4.74 AU |
| Mission | Deep Impact strike 2005, Stardust revisit 2011 |
Figures are representative approximations. Source: compiled from NASA and IAU public data.
Frequently asked
- How long is the orbital period of Tempel 1?
- 5.58 yr.
- How far is Tempel 1 from Earth?
- 1.54~4.74 AU.
- In one line, what is Tempel 1?
- Comets — The first comet humanity deliberately hit.
What the impact revealed — a nucleus fluffier than snow
When Deep Impact's copper impactor struck the nucleus on 4 July 2005, far more dust flew up than expected, and far finer: the plume hid the camera's view for days, and the grains were finer than talcum powder. The nucleus's calculated porosity came out around 75 percent — three-quarters empty space, fluffier than snow, meaning the whole body is a loosely bound heap of dust and ice.
The ejecta contained not only water ice but clays, carbonates and aromatic hydrocarbons. Clays and carbonates form only where liquid water has been, so they are read as evidence that dust was mixed from the hot inner solar system to the cold outskirts as the planets formed. When Stardust returned in 2011 the impact site was a shallow crater 150 m across, and cliffs on the surface had retreated by tens of metres in the six years between.
The comet in depth
Comet Tempel 1 is a Jupiter-family short-period comet discovered in 1867 by German astronomer Ernst Tempel in Marseille. It travels from 1.54 AU, near Mars's orbit, out to 4.74 AU near Jupiter's every 5.58 years; its potato-shaped nucleus measures 7.6 × 4.9 km. Repeated encounters with Jupiter nudge its orbit, and for a time astronomers lost track of it altogether.
On 4 July 2005 NASA's Deep Impact released a 370-kg copper impactor that struck the nucleus at 37,000 km/h — the first experiment to excavate a comet's interior. Far more fine dust, water ice and organic material sprayed out than expected, showing the nucleus to be less a dirty snowball than a fluffy dust pile. In February 2011 the Stardust-NExT spacecraft returned and photographed the crater, roughly 150 m wide, and found the surface visibly changed after a single trip around the Sun.
Track Tempel 1 in the orbit view to see its short ellipse shuttling between Mars and Jupiter. Its next perihelion falls around September 2027, when ground-based observers will check how Deep Impact's scar has evolved.
Related
Figures are representative approximations. Simulated positions use J2000 mean elements.