Asteroid Hunt!

This may save the Earth one day!

 

Artist’s impression of an asteroid impact resulting in the extinction of 

dinosaurs on earth 65 million years ago

 

Why do Asteroids matter

The dinosaurs that once inhabited the earth became suddenly extinct about 65 million years ago, most probably due to the impact of a giant asteroid. If such a rare natural event were to occur today, it could produce the same effect as the simultaneous triggering of all the nuclear arsenal stockpiled by all the superpowers in the world, wiping out most of humanity on the already fragile planet. It is a sobering thought that the same nuclear arsenal can possibly be used on such a rogue asteroid to divert it from its catastrophic collision course and save the earth from an impact. However, this would require the ability to detect such an existential threat far in advance and initiate the necessary war-like measures, collectively against a common enemy instead of against each other. This can be achieved only through an extensive and systematic scientific study of the asteroids and other such extraterrestrial objects. Luckily, such studies are already under way and I feel privileged to describe a typical case study involving my long-time acquaintance and associate Ms Ilavenil T (see picture below), a science educator and amateur astronomer, who is part of the K-12 Learning Solutions team of Excel Technologies, Mysore, India, with an MPhil degree in Theoretical Physics.

What are Asteroids

Students learn briefly about stars and the solar system in their high school classes. For the majority, it is through a short chapter that describes the Sun, the Moon, stars and planets. Asteroids, if they are mentioned, are just “small rocky bodies that orbit the Sun between the orbits of Jupiter and Mars.”

In reality, asteroids are intriguing objects that are also found in a number of clusters other than in just the “Main Belt” between Jupiter and Mars (see drawing below). They contain the secrets of the early solar system, interact with each other often enough to improve our knowledge of gravitational perturbation among the objects of the solar system, and some of them at least are also known to be made up of rare minerals. Near-Earth Asteroids (see the map below), which cross the orbit of the Earth, have the capability of unleashing huge destruction on the Earth if they get close enough for a possible impact, something that is known to have occurred disturbingly frequently during the long history of life on our planet. To forestall such an eventuality, it is imperative that we discover them and map their orbits accurately, as early as possible. More importantly, we need to keep a constant surveillance on them, especially to see if any of them head towards the Earth as a result of gravitational perturbations produced by any of the large objects of the solar system, like Jupiter for example.

The main asteroid belt between Mars and Jupiter.
Ceres and Vesta are two of the largest asteroids within this belt.

Near-Earth Asteroids in 2013

The asteroids (also called minor planets), as also meteoroids and comets, are the remnants of the formation of the solar system about 4.5 billion years ago. At least 1.3 million of them are known, and together their mass is less than that of the Moon.  However, millions more are yet to be discovered and catalogued, most of them are very small and in highly irregular orbits.  These form the focus of attention under several asteroid search campaigns involving not only professionals but also amateurs and students.  For the students, it is a learning-by-doing opportunity to work with the professionals and teachers.

Asteroids are irregular rocky objects of widely varying sizes, from as small as a few metres across to as large as Vesta whose size is about 530 km across. Four of them – Vesta, Ceres, Pallas and Juno – together constitute about 75% of the total mass. Their pictures are shown below:

Asteroid Search Campaigns

The International Astronomical Search Collaboration (IASC) runs asteroid search campaigns for school students. The home page of IASC is at http://iasc.cosmosearch.org. They provide software and access to photographs from the PanSTARRS* telescopes in Hawaii (see picture below). It is a unique opportunity for students to access real data and contribute to the corpus of human knowledge.

[*The Panoramic Survey Telescope & Rapid Response System (Pan-STARRS or PS1) is a wide-field imaging facility developed at the University of Hawaii's Institute for Astronomy for a variety of scientific studies from the nearby to the very distant Universe]

 

Ilavenil’s involvement

Ilavenil’s involvement in the asteroid search campaigns started in 2017. A colleague of hers had come across an application for an asteroid search campaign conducted by ‘Global Astronomy Month’, and she guided some of the students of Excel Public School in taking part in it.

After guiding the students a few times, she had the opportunity to meet Dr Patrick Miller, the director of IASC in the ‘Global Hands-on Universe’ conference in Haute-Provence Observatory, France, in 2019. When she returned to India, ‘Hands-on Universe India’ was starting off their asteroid search campaigns, and she began helping them out too. This led to her helping more people, and being approached by groups from different parts of India.

In 2022, she was given an opportunity to be a regional trainer for India, which she happily accepted with the permission and encouragement of her employers, Excelsoft Technologies. Here is what she does as a trainer:

Ilavenil’s work ranges from answering a simple query on email such as how to input a name in the proper format to teaching the whole process. Often, she is asked to do a workshop for a single team, or several teams at once. She takes them through the process of installation, loading images, analysis, generating reports and submitting them to the Minor Planet Centre that operates at the Smithsonian Astrophysical Observatory, Harvard University.

Students enrolled in the program receive datasets with images like the following:

Each dataset has 4 images, taken seconds apart. Most of the dots in the images are stars. The software allows them to ‘blink’ the images one after the other. When this is done, the stars which are in the same position in all the images remain static, while any non-stationary body shows up as a dot moving in a straight line.

This was the same process used by Clyde Tombaugh to discover Pluto, then considered to be a planet, in 1930. Of course, back then he was working with a mechanically operated blink comparator, a device where large glass photographic plates were physically moved with a lever. This technique was so efficient that it led to the discovery of many minor planets and to the creation of the Minor Planet Centre in 1947. Advances in software have made this technique vastly more accessible and a lot less laborious. Thanks to the modifications done to the Astrometrica software by Dr Miller and his team, the process of marking these objects and generating the reports is incredibly simple. However, the concentration and perseverance needed to spot a moving object is still the same. 

The blink comparator used to discover Pluto

After the first couple of campaigns, Ilavenil realised that the students did not fully understand what they were looking at and this led to some disinterest and lack of perspective. The picture below is just an illustrative example of a student’s question when even the brightest stars in the image are of magnitude 19! 

From then on, she started including a little astronomy in her sessions to bring necessary context to the students. The inputs included the celestial coordinates, magnitudes and the magnification that is produced by a typical 1.8m telescope.

Once a campaign is over, a list of discoveries is published by IASC. Ilavenil usually acts as the point of contact when student teams participate in the search for the first time. So, when the list of discoveries shows any students’ names, she calls the concerned students to inform them. She has done this so many times that she can’t recall all of them, but the joy and excitement are unforgettable.

The achievements

Once students submit their reports, their discoveries are confirmed through multiple tiers – preliminary discoveries which are the first observations of a moving object, confirmed by automated systems, provisional discoveries that are published once a part of the orbit has been traced by multiple observations of the same moving object, and then a confirmation once the whole orbit has been observed. Typically, the whole process takes place over a period of four to six years. Preliminary discoveries are published within weeks of completion of a campaign, provisional discoveries after approximately a year thereafter. Confirmation of an asteroid discovery takes approximately three to five more years.

So far, she has guided students to (at least) 460 preliminary discoveries and 30 provisional discoveries.

One student team she guided has also been credited with observing a ‘faint provisional’ which is an asteroid that was too faint for the automated system to spot at the initial stages..

Since 2022, Ilavenil has been working with Mr Amoghavarsha, Project Coordinator for COSMOS-Mysuru project, which is a precursor to the state-of-the-art digital planetarium coming up in Mysore, scheduled for completion next year under the leadership of the Indian Institute of Astrophysics, Bangalore. Under the COSMOS banner, students have taken part in four campaigns so far and a fifth is in progress.

Very recently, Ilavenil and a teammate were credited with the provisional discoveries of two asteroids. These have been given the labels 2022 QO73 and 2022 QO258. Their tentative orbits as seen in the JPL Small Body Database are shown in the graphics below. 

It would be nice to have these two asteroids (see certificates of appreciation appended below) confirmed and listed in the Minor Planet Centre (Harvard). However, the number of students she has guided is what she considers as a greater achievement. She is working on making the search more accessible by developing a procedure to do it on a computer with Linux OS, and on the logistics of taking the search to rural students.

Postscript

Carrie Nugent (see picture below) is a specialist in the study of near-Earth objects, including asteroids that pose a potential threat to the planet. She was part of the Near-Earth Object Camera asteroid hunting teams. For this, Nugent was awarded the NASA Group Achievement Award. She believes asteroid impact is the only natural disaster that we can prevent. How can this be done in practice? An exciting and successful small-scale trial has already been conducted by space scientists. More about this and other possible efforts in a future blog article. 

The asteroid 8801 Nugent was named after Carrie Nugent. I hope Ilavenil will soon have one named after her in just reward for her own asteroid hunting activities.

Carrie Nugent is also a famous science communicator. I would like to sign off on a positive note with the following reassuring words from her: 

“An asteroid impact is a preventable natural disaster. It's in part preventable because we have the technology, and it's in part preventable because it's predictable.”

These could as well be the words of Ilavenil!