NASA knows that with the launch of a new generation of telescopes, this number will increase significantly. We need the help of detailed astronomical theory and reliable software to observe the orbits of many celestial bodies at the same time and to detect the possibility of collisions with the Earth in a timely manner. NASA has been using the Sentry software, developed by Jet Power Laboratory (JPL) in 2002, for the past two decades.

Javier Rowe Vincent, head of the Sentry software project, said: “Sentry’s first generation is very powerful and has been in operation for about 20 years. It uses very good mathematical algorithms.

Wisense said the recently upgraded Sentry-II (Sentry-II) is more robust and everything can be calculated faster.Near-Earth asteroidMore importantly, it includes astronomical components not considered by first-generation software, and the calculation results are more accurate – it can accurately estimate the probability of an impact of only a few tens of millions.

Sentry II considers two new astronomical components. One, the effect of the Sun’s heat on the orbits of the asteroids; Another is the effect of Earth’s gravity on these celestial bodies when the asteroid is very close to Earth.

The first element is also called the Yarkovsky effect (Yarkovsky effect). Asteroids can rotate like normal planets. During rotation they change day and night. As the heated side enters at night and begins to cool, the infrared energy it emits creates a small thrust on the asteroid. Scientists call this the Yalkovsky effect. It has little or no effect on the asteroid’s orbit for a short time, but in a matter of decades or hundreds of years, the impact will have accumulated considerably.

Another improvement on the Sentry Generation algorithm is how the asteroid’s gravity will deflect it as it passes close to the Earth. In this case, the scientists found that changes in the asteroid’s orbit would be of great uncertainty, with Sentry Generation software requiring manual intervention and adjustment at this time. The second generation of sentry uses a new algorithm that can also make accurate predictions in this situation.

With the opening of NASA’s New NEO Surveyor and the Chilean Vera, Rubin Observatory (Vera C. Rubin Observatory), Vicens said that a small proportion of all asteroids near Earth are affected by specific factors mentioned above. The number of asteroids that we need to evaluate quickly will increase significantly. We must be prepared. “

The research was published in The Astronomical Journal on December 1. ⁇

Editor-in-Charge: Ye Ziwei