Interstellar visitor
ʻOumuamua
ʻOumuamua is a visitor from another star! In 2017 it flew through our Solar System just once, and it is already on its way out again. It is long and thin like a cigar and gave researchers a big surprise.
Fact file
- Type
- Interstellar visitor
- Diameter of the nucleus
- 0.2 km
- Orbit
- open (hyperbola) – will never return
- Closest point to the Sun
- passed on 9 September 2017
Interesting facts about ʻOumuamua
- ʻOumuamua is the first object proven to have come to us from another star – discovered on 19 October 2017 in Hawaii.
- The name is Hawaiian and means roughly “a messenger from afar arriving first”.
- It is probably long and flat like a cigar or a pancake, and it sped up ever so slightly without any visible tail – a mystery to this day.
Origin
It comes from another planetary system and had probably been travelling between the stars for millions of years before it crossed our Solar System.
Coma and tail
No coma, no tail – even though it came closer to the Sun than Mercury. Perhaps it was pushed along by evaporating hydrogen or nitrogen ice, which cannot be seen.
Exploration
By the time it was discovered, it was already on its way out. Telescopes could observe it for only a few weeks. Today a probe would have a hard job catching up with it.
Connection with Earth
It raced in from space at 26 km/s – so fast that the Sun cannot hold on to it. It will never come back.
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