Planetary Defense Conference 2019 has started yesterday. For those who are not sure what that is - every two years, asteroid experts from across the globe come together to pretend an asteroid impact is imminent. During these week-long impact scenarios, participants don’t know how the situation will evolve from one day to the next but must make plans based on the daily updates they are given. Very fascinating exercise to see how such a scenario could play out and ESA is covering it live this year...
This year’s asteroid – "2019 PDC"
The scene has been set for this year’s hypothetical impact scenario. Although realistic, it is completely fictional and does NOT describe an actual asteroid impact.
— An asteroid was discovered on 26 March 2019 and has been given the name “2019 PDC” by the IAU’s Minor Planet Center.
— Initial calculations suggest the orbit of 2019 PDC will bring it within 7.5 million km of Earth’s orbit. (Or, within 0.05 AU of Earth’s orbit. One AU is the mean distance between the Sun and Earth, equal to 149 597 870.7 km).— 2019 PDC is travelling in an eccentric orbit, extending 2.94 AU at its farthest point from the Sun (in the middle of the main asteroid belt), and 0.94 AU at its closest. It completes one full orbit around the Sun every 971 days (2.66 years). See its orbit in more detail here.
— The day after 2019 PDC is discovered, ESA and NASA’s impact monitoring systems identify several future dates when the asteroid could hit Earth. Both systems agree that the asteroid is most likely to strike on 29 April 2027 – more than eight years away – with a very low probability of impact of about 1 in 50 000.
— When it was first detected, asteroid 2019 PDC was about 57 million km from Earth, equal to 0.38 Astronomical Units. It was travelling about 14 km/s, and slowly getting brighter.
— As observations continue, the likelihood of an impact in 2027 increases. Three weeks after the discovery, after observations were paused during the full Moon (and reduced visibility), the chance of impact has risen to 0.4% – that’s a chance of 1 in 250.— Very little is known about the asteroid’s physical properties. From its brightness, experts determine that the asteroid’s mean size could be anywhere from 100-300 meters.
— Asteroid #2019PDC continued to approach Earth for more than a month after discovery, reaching its closest point on 13 May. Unfortunately, the asteroid was too far away to be detected, and it is not expected to pass close to Earth until 2027 – the year of impact.
— Astronomers continued to monitor the asteroid for a month after its initial detection, which provided them with more information about the object’s trajectory, and have now discovered that the chance of impact is rapidly increasing. By 29 April 2019, (the first day of the Planetary Defence Conference), the probability of impact has risen to 1 in 100.
Day 1:
Asteroid impact chance 1 in 100.
Day 2:
Four months after asteroid 2019 PDC is detected, observations now show the chance of Earth impact has increased to 1 in 10.
All the live updates here on ESA's twitter... https://twitter.com/esaoperations
Or the website: https://blogs.esa.int/rocketscience/2019/04/25/hypothetical_impact/