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By Cheryl Kahla

Content Strategist


Potentially hazardous Asteroid 2015 FF to zip past Earth at 27x the speed of sound

Asteroid 2015 FF is roughly the size of a blue whale, or two school buses lined up.


A potentially hazardous asteroid named 2015 FF will be zipping past Earth today at 33 000 kilometres per hour (km/h) – roughly 27 times the speed of sound.

For context: The speed of sound at sea level is approximately 1 225 km/h. Granted, this is on Earth with gravity and all that, and assuming air temperatures are 15 degrees Celsius.

But still. That’s pretty fast, no?

Asteroid 2015 FF

Our friendly (or not so) space visitor measures between 13 and 28 metres.

Going at speeds of 33 000km/h, it will pass by Earth shortly after 10am SA time, at 4.3 million kilometres which is eight times the distance between the Earth and the Moon.

So we’re safe, for now. That said, Asteroid 2015 FF has an absolute magnitude (H) of 26.6, which means it definitely has NASA’s attention.

WATCH: Asteroid live stream

What is a ‘potentially hazardous’ asteroid

A potentially hazardous object (PHO) is a near-Earth object (NEO) which is large enough to cause regional damage if it were to hit Earth.

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.

Instead, scientists at Nasa and the Jet Propulsion Lab use the more practical measure of absolute magnitude (H).

Near-Earth-Objects

Near-Earth-Objects (NEO) zip past Earth all the time. In fact, another three will pass by our region of the universe over the weekend.

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.

An Apollo-class asteroid orbits our Sun and could potentially, at some point in its trajectory, intercept Earth’s orbit.

A busy ‘asteroid week’

Between now and 29 August, nine other asteroids of similar absolute magnitudes will be passing by Earth, none of which really poses a threat until it somehow changes course.

Asteroid 2022 OT1 measures 59 metres (roughly double the size of 2015 FF) and will pass by Earth tomorrow; it has an absolute magnitude of 25.

Meanwhile, 2022 OA4 will pass by on 14 August; also measuring bigger than that of today’s visitor, with an absolute magnitude of 26.

2022 PJ1 and 2022 PW will both pass by on the 16th, and the largest rock this month, 2019 AV13, will swing by our region of space on 20 August, measuring a whopping 230m in diameter.

ALSO WATCH: James Webb Space Telescope hunts for first stars and habitable worlds

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