Comets are often described as “dirty snowballs,” lumps of ice, dust, and rocky material. Though many comets are rather small, a number of truly gigantic comets have turned up that offer quite a bit of insight into the early Solar System.
Comet Bernardinelli-Bernstein: Giant of Records
In 2014, astronomers Pedro Bernardinelli and Gary Bernstein made a discovery in archival images from the Dark Energy Survey of an enormous object. Now designated Comet C/2014 UN271 (Bernardinelli-Bernstein), this comet hosts an estimated diameter of its nucleus of about 80 miles (129 kilometres), making it the largest comet nucleus yet detected.
The comet’s mass is estimated to be around 500 trillion tons, which is about 100,000 times greater than that of a typical comet. Currently, Bernardinelli-Bernstein is approaching the Sun and will reach its closest point, or perihelion, in 2031. However, it will remain at a distance just outside Saturn’s orbit, making it unlikely to be visible to the naked eye.
Comet Hale-Bopp: The Great Comet of 1997
Indeed, besides Bernardinelli-Bernstein, one of the most renowned large comets is the so-called Comet Hale-Bopp, provisionally designated as C/1995 O1. Hale-Bopp was discovered in 1995 and then widely seen by naked-eye observers in 1997. The estimated diameter of its nucleus is about 37 miles (60 kilometres), one of the largest cometary nuclei known at that time.
Hale-Bopp’s brightness and long period of visibility provided astronomers with a wealth of data, enhancing our understanding of cometary composition and behaviour.
Comet Swift-Tuttle: A Potential Hazard
The famous Comet Swift-Tuttle, 109P/Swift-Tuttle, was discovered in 1862 and has a nucleus about 16 miles (26 kilometres) in diameter. It is not the largest, but it has been regarded as important because of its orbit, which brings it close to Earth’s orbit. As a consequence, it has been one of the favourite targets of speculation concerning its possibilities as a future impact hazard.
Its most recent perihelion was in 1992, and it will not approach Earth again until the year 2126. It is considered a potentially hazardous asteroid, but current calculations show no possibility of collision.
The Significance of Large Comets
Such studies and discoveries, like that of Bernardinelli-Bernstein and Hale-Bopp, are significant in many ways:
- Insights into the Early Solar System: Comets are considered to be the remnants of the early Solar System. Investigation into their composition may yield important clues to materials that were present at their formation.
- Understanding Cometary Activity: Large comets offer opportunities to observe cometary activity, such as outgassing and tail formation, over extended periods and at greater distances from the Sun.
- Assessing Potential Threats: Identifying and tracking large comets helps assess potential impact threats to Earth and develop possible mitigation strategies.
Future Observations and Missions
With the advances in technology, there is a likelihood that astronomers are still going to find large comets. This would be so because future missions and observatories will enhance capabilities for the investigation and detection of such faraway objects among which Vera C. Rubin Observatory comes forward.
For example, it is the future mission of the European Space Agency, Comet Interceptor, planned to be launched in 2029, reaching a long-period comet or, alternatively, another interstellar object, adding a bit more information about these real ancient travellers in space.
Conclusion
This should highlight that great comets, like Bernardinelli-Bernstein, show how remarkably dynamic and variant our solar system really is. In such huge bodies, from simple human curiosity to the actual study, high levels of interpretation concerning the constitution and evolution of the solar system are informed through study.
In fact, while the techniques for observation get progressively better, an array of such celestial giants may be found, and a number of these secrets unravel.