MIAMI.-Un asteroide de aproximadamente un kilómetro de diámetro pasará este martes lo más «cerca» de la Tierra de lo que lo hará en los próximos dos siglos, pero en principio no supone un riesgo para el planeta pues el paso será a una distancia de 1,9 millones de kilómetros.
A diferencia de la amenaza descrita en la reciente película «Dont Look Up» (No miren arriba), el asteroide 7482 1994 PC1, de más del doble del tamaño del edificio neoyorquino Empire State, «volará con seguridad más allá de nuestro planeta» en la tarde de hoy, según anunció la NASA.
Descubierto en 1994 por los científicos de la NASA, el asteroide se mueve a 47.344 millas por hora (76.192 km/h), de acuerdo al Centro de Estudios de Objetos Cercanos a la Tierra de la NASA, la división de la agencia aeroespacial que rastrea cometas y asteroides que podrían colisionar con el planeta.
Según la NASA, la trayectoria del objeto alcanzó su punto más cercano al planeta a las 4.51 de la tarde de hoy, hora del este de EE.UU. (21.51 GMT) y será el asteroide que más cerca pase del planeta en los próximos 200 años.
Medios especializados destacan que no podrá ser visto desde la Tierra a simple vista, pero sí con un pequeño telescopio.
Could an asteroid hit earth? Why the planet is unlikely to be struck by meteor and how close today’s will pass
A giant asteroid is set to pass Earth on Tuesday at a speed of 43,754 miles per hour.
The asteroid is called (7482) 1994 PC1 and is more than a kilometre long – roughly two-and-a-half-times the height of the Empire State Building.
Its passing is considered “close” to Earth, and as such is classed as a “potentially hazardous asteroid”.
However, there is no need to worry as “close” in space terms does not mean the same as “close” to you and me – the asteroid will pass about 1.93 million km (1.2 million miles) from Earth.
How likely is an asteroid to hit Earth?
Small objects frequently collide with Earth, many of them so tiny no one even notices, as they get burnt up as they enter Earth’s atmosphere.
The larger an object is, the less likely it is to strike.
Researchers have found that asteroids with a 1km diameter strike Earth every 500,000 years on average.
Large collisions – with 5km objects – happen approximately once every 20 million years.
The last known impact of an object of 10km or more in diameter was the Chicxulub asteroid that killed off the dinosaurs 66 million years ago.
The asteroid Bennu – which has a diameter of 525m – is believed to be the most likely to strike Earth. Research published earlier this year gave it a one in 1,750 chance of colliding in the next three centuries.
Late last year Nasa launched its first ever mission that will see a spacecraft deliberately crash into an asteroid.
The Double Asteroid Redirection Test (Dart) mission blasted off from Vandenberg Space Force Base in California in November.
It will test whether striking an asteroid can have enough impact that, in a hypothetical future where an object was headed directly for our planet, this technique could be used to protect us.
It will travel roughly 6.8 million miles on its 10-month journey to Dimorphos.
Dimorphos is a “moonlet” about 160m wide. It orbits a larger asteroid called Didymos. It was chosen due to its proximity to Earth and the ability to measure its movements with a telescope.
The Dart capsule will strike the asteroid at a speed of 15,000mph, which should change its speed by a fraction of a millimetre per second. This would be enough to knock an object heading for Earth off course.
Kelly Fast, of Nasa’s Planetary Defense Coordination Office, said: “Dart will only be changing the period of the orbit of Dimorphos by a tiny amount. And really that’s all that’s needed in the event that an asteroid is discovered well ahead of time.”
What do we know about (7482) 1994 PC1?
The asteroid was discovered on 9 August 1994 by Scottish-Australian astronomer Robert McNaught at the Siding Spring Observatory in Coonabarabran, Australia.
On 17 January 1933 it made its closest known approach to Earth of 1,125,400km (699,300 miles).
It is not predicted to come as close to Earth again until 18 January 2105.
The asteroid belongs to the Apollo asteroid group – the most common group of asteroids we know of.
When it passes Earth on Tuesday it will be travelling at 19.56 kilometres per second.
Nasa’s Asteroid Watch Twitter account posted: “Near-Earth asteroid 1994 PC1 (approximately 1km wide) is very well known and has been studied for decades by our planetary defence experts.
By Alex Finnis