How to interpret news stories on asteroid close approaches
Asteroids are a topline and evergreen topic for SEO because of the tremendous interest it generates. News sites often publish any nonsense to grab eyeballs instead of using the interest among readers as an opportunity to for authentic communication on the topic.
News sites often report on close approaches by asteroids, which are typically based on tables published by NASA’s Center for Near Earth Object Studies. There are however some careless news sites or those who depend on machine generated content, that do not care about the designations of the asteroids, and accurate values or dates about their close approaches. The news channels can also swap out real asteroids for fake close approaches, and when a whole bunch of careless sites copy from each other, these stories end up showing on platforms such as Google News.
Memes showing disappointment when asteroid strike does not happen. (Image Credit: News9).
NASA has never issued an alert for a threatening asteroid. The threat of potential impacts are represented on two scales, the Torino Scale for communicating the impact risk more broadly and the Palermo Scale for communicating the impact risk about scientists studying asteroids. Some objects such as 2013 TV135, 2011 AG5 and Apophis briefly had Torino scale values of more than 0, but are now back at 0, on a scale of 10. The Palermo Scale indicates significant risk after the value of 2, with Bennu having a value of -1.59 for a 2182 impact, which is one of the highest impact risks on the scale. NASA is closely monitoring the asteroid, but no large asteroid is expected to impact the Earth for the next few centuries at least.
How are asteroids named?
Asteroids are given a provisional designation based on the year they were initially spotted, followed by an alphanumeric string for that year. Once the asteroids are confirmed, the discoverer gets to name them, a tradition followed since the discovery of the first asteroid 1 Ceres discovered by the Italian astronomer Giuseppe Piazzi on 1 January 1801. A recently assigned name after an outreach activity was 164207 Cardea. News sites can entirely make up these designations, or fudge the dates and orbital parameters according to their convenience, so it is important to be wary and skeptical.
Asteroids are numbered and named in the order of their discovery. (Image Credit: NASA).
Most of the asteroids in the Solar System occupy the main belt between Mars and Jupiter, but there are populations of asteroids distributed throughout the Solar System. The Earth orbits the Sun at 1 Astronomical Unit (AU). Asteroids that approach within 1.3 AU of the Sun are considered near Earth objects (NEOs). A subset of these are Potentially Hazardous Asteroids (PHAs) that can cause significant regional damage if they impact the Earth. Most of the close approaches are by groups of asteroids called Atens, Apollos, Amors, Atiras and Arjunas, which have orbital parameters that make them frequent visitors of the Earth. These close approaches are frequent, and there are dozens every month. There is no cause for alarm because of these close approaches.
How to check for close approaches?
Readers interested in looking up the close approaches themselves can do so on the CNEOS website. NASA’s Eyes on Asteroids website allows you to track individual asteroids in a realtime plot of the Solar System. The timing and object selection can be manipulated to see visual representations of future encounters, such as the close approach by Apophis on 13 April 2029. ESA’s Near Earth Object Coordination Center also tracks close approaches. The ESA also maintains an impact risk list, and so does NASA. NASA also publishes tables of newly discovered Near Earth Objects, which are subsequently analysed by the Scout programme.
There may be fewer asteroids than suggested by previous estimates. (Image Credit: NASA).
Only recently, humans have developed the capabilities of predicting certain impactors before they strike the planet. These are small asteroids that are spotted a few hours or at best days before they impact the Earth, which mostly involves burning up in the atmosphere of the Earth. All the spacefaring nations around the world are investing in the infrastructure necessary to spot more Near Earth Objects, and better characterise their orbits. Astronomers hope to discover 90 per cent of all NEOs larger than 140 metres wide in the Solar System by the end of the decade. We have discovered less than 40 per cent of this population, which can potentially cause regional devastation on striking the planet.