Planetary Defense Mission: February 2021
On February 21, Unistellar citizen astronomers can take part in a rare and daring challenge: to observe infamous Near-Earth Asteroid (NEA) 99942 Apophis! Will it destroy spacecraft and satellites, or make catastrophic, direct contact with Earth? Citizen astronomers can benefit from the decentralized Unistellar network to help expand our knowledge of this Potentially Hazardous Asteroid (PHA), which will fly between Earth and our Moon in 2029 — close enough to destroy communications satellites.
Apophis is one of the most important near-Earth asteroids to observe, due to its 340-meter size combined with upcoming flybys in 2029, 2036 and 2068. In 2029, Apophis will pass only 19,794 miles (31,860 kilometers) from our planet’s surface, even closer than large communication satellites. And in 2068, the chance of Apophis hitting the Earth is 1 in 150,000… odds that don’t seem in our favor, when you consider that its impact could destroy metropolitan areas.
This is why your observations of Apophis are so critical — they will help nail down uncertainty in its orbit and position. While you are aiding in our understanding of Apophis, you are also helping defend our planet!
You are invited to participate in a rare opportunity to observe Apophis with your eVscope!
On February 21, at approximately 11:50 PM Central Time, Apophis will occult (pass in front of) a star, visible from a path sweeping across the United States. This prediction was sent to us by our colleagues at the Observatoire de Paris — this is a truly international project involving researchers around the world. Unlike most consumer telescopes, the eVscope has enough power and precision to document this rare event and help astronomers expand our knowledge about this NEA.
Quick Facts about asteroid Apophis:
- Belongs to the subgroup of near-Earth asteroids (NEAs) known as Aten asteroids, that cross Earth’s orbit and bring them in close proximity to Earth
- Many Aten asteroids are classified as potentially hazardous asteroids
- Diameter: about 340 meters (1,116 feet)
- Discovery: June 19, 2004
- Has a very low probability of impact (1 in 150,000) in 2068
In order to observe this occultation of Apophis, you will have to be located along (or within traveling distance of) the path as seen in the image below:
If you’re not located along this exact path and want to observe this occultation, you will have to travel to see it. Consider a weekend trip to observe this special occultation! You can find the path of the occultation on our website. The path of the occultation is very accurate, with an uncertainty of only 7 km. Please note, however, that this path may change slightly, and we will update our website accordingly.
“One of the main mysteries about Apophis is how its orbit changes when the asteroid is illuminated by the Sun. This effect, called ‘Yarkovsky,’ is very difficult to simulate, so a direct observation of an occultation will give us an extremely accurate estimate of the position of the asteroid, typically 400 m,” said Franck Marchis, senior astronomer at the SETI Institute and Chief Scientific Officer at Unistellar.
“Additionally, if a citizen astronomer succeeds in detecting this occultation, it will be the smallest asteroid ever detected by occultation, so that could be another trophy to add to our wall of success, but it will also show that we can do this kind of measurement reliably for future Near Earth Asteroids.”
“With the demise of the Arecibo telescope, it has become more difficult to accurately measure the position of asteroids during a flyby. Measuring asteroids’ occultations through the Unistellar network could be the best way to learn about their whereabouts in the future.”
Interested in detecting Apophis with your eVscope? Check out our blog post with detailed instructions.