The Apollo-class Phaethon asteroid – which has its origins in the famous Geminids meteor shower – has been baffling astronomers this week.
Phaethon asteroid mystery
An Apollo-class asteroid is a space rock which orbits our Sun and could, at some point in its trajectory, intercept Earth’s orbit and cause all sorts of chaos for us.
In fact, the asteroid’s moniker testifies to this, as it was named after the Phaëthon, son of the sun god Helios in Greek mythology. It’s also known as 3200 Phaethon or 1983 TB.
Watch: How dangerous is Phaethon?
Phaethon passes by our Sun closer than any other known asteroid. At a distance of 20.9 million km, it’s less than half of Mercury’s perihelial distance.
Space rock speeds up
The giantic 6 km-space rock is making headlines after scientists noticed the speed of its rotation accelerating drastically.
Planetary scientist Sean Marshall said the model’s predictions did not match the data “due to the fact that Pheathon’s rotation period changed slightly at some point”.
Marshall says a possible explanation “would be related to cometary activity at the time when it was closest to the Sun”.
Mysterious blue space rock
Phaethon has baffled scientists for decades. It has peculiar characterists, such as it’s orbit resembling that of a comet, not an asteroid.
It has therefore been dubbed as the ‘rock comet’. NASA also observed the asteroid’s rapid brightening and dust tail in 2009, and again in 2012.
Scientists believe the Sun’s heat and radiation – which increases significatly the closer Phaethon gets to the sun – causes fractures similar to mudcracks in a dry lake bed.
Scientists also realised in 2018 that Phaethon was blue in colour – an extremely rare occurance as most asteroids are red or grey.
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Asteroid flyby in 2028
In order to understand Phaethon better – and by extension, the threat it poses to Earth – Japanese space agency JAXA is planning a flyby within the next six years.
JAXA’s DESTINY+ probe (Demonstration and Experiment of Space Technology for INterplanetary voYage with Phaethon fLyby and dUst Science) will launch in 2024 and reach the asteroid by 2028.
The probe will be equipped with a Dust Analyser from the German Aerospace Center, as well as a Telescopic Camera (TCAP) and Multiband Camera (MCAP).
Near-Earth-Objects (NEOs) zip past Earth all the time.
NASA monitors more than 29 000 NEOs which pass within 48 million kilometres of Earth’s orbit. Out of those, only 15 000 are classed as Apollo-classed asteroids.
Keep in mind: a “small” asteroid measuring 35 metres could easily level an entire town or city. However, the size of the asteroid is not the most reliable factor.
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