Little White Streak: One Man’s Introduction to Planet Hunting

Siddharth Mehrotra
4 min readOct 24, 2020


A few years ago, in the effort to discover whether we on Earth are truly alone in the galaxy, NASA recently launched the Transiting Exoplanet Survey Satellite (TESS): a probe intended to measure the light of nearby stars, and detect the miniscule variations in that light, which might indicate the ‘transit’ of planets across the disc, and so reveal whether each star has planets at all, and of what size and number. So many pictures are taken, in the course of these findings, the research team offers them to hundreds of volunteers, whose business is to examine every photograph taken by the probe, in search of the tell-tale interruptions in the brightness of each star. The pictures deemed to show such clues, are thereafter examined again by experts, to confirm or deny the volunteers’ opinions, and ascertain the size and orbit of these newly-discovered worlds. Over the last 2 years, dozens of new planets are found by this method, and counting.

Working with the findings of the TESS, even as a volunteer, is enough to inspire the same thoughts and feelings, and for much the same reasons, as those of the late, great Carl Sagan’s famous ‘Pale Blue Dot’ speech, reproduced below:

“Look again at that dot. That’s here. That’s home. That’s us. On it everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives. The aggregate of our joy and suffering, thousands of confident religions, ideologies, and economic doctrines, every hunter and forager, every hero and coward, every creator and destroyer of civilization, every king and peasant, every young couple in love, every mother and father, hopeful child, inventor and explorer, every teacher of morals, every corrupt politician, every “superstar,” every “supreme leader,” every saint and sinner in the history of our species lived there — on a mote of dust suspended in a sunbeam.

The Earth is a very small stage in a vast cosmic arena. Think of the rivers of blood spilled by all those generals and emperors so that, in glory and triumph, they could become the momentary masters of a fraction of a dot. Think of the endless cruelties visited by the inhabitants of one corner of this pixel on the scarcely distinguishable inhabitants of some other corner, how frequent their misunderstandings, how eager they are to kill one another, how fervent their hatreds.

Our posturings, our imagined self-importance, the delusion that we have some privileged position in the Universe, are challenged by this point of pale light. Our planet is a lonely speck in the great enveloping cosmic dark. In our obscurity, in all this vastness, there is no hint that help will come from elsewhere to save us from ourselves.

The Earth is the only world known so far to harbor life. There is nowhere else, at least in the near future, to which our species could migrate. Visit, yes. Settle, not yet. Like it or not, for the moment the Earth is where we make our stand.

It has been said that astronomy is a humbling and character-building experience. There is perhaps no better demonstration of the folly of human conceits than this distant image of our tiny world. To me, it underscores our responsibility to deal more kindly with one another, and to preserve and cherish the pale blue dot, the only home we’ve ever known”.
— Carl Sagan, Pale Blue Dot, 1994
Copyright © 1994 by Carl Sagan, Copyright © 2006 by Democritus Properties, LLC.

Every astronomer and technician on the TESS project, and every participant therein down to the lowliest volunteer, sooner or later must think the same: must wonder, at the countless comings and goings, the endless comedies and tragedies, the heroisms and villainies, the joys and sorrows, the lifelong efforts which seem so important to the natives of each scarcely-visible planet, and yet prove ephemeral in the end, all added up to one single tiny streak on a photographic plate; to a little irregularity, no more than the blink of an eye, in the light of their star. One must wonder, at the sight of all the striving of billions of years’ worth of trillions of living creatures, and all the accidents they suffer, all amounting, indeed, to no more than a moment in the sun. This brief, bright moment represents the entire history of their world, from start to finish, as far as it can be seen by others; and we, too, are no more than a similar blink in their instruments, whatever those might be. If they are watching us (and it is unlikely that none of them are), we, too, are no more than a fly’s shadow across a lantern; a skipped beat in the music of the spheres.

It is a humbling thought: horrifying to some, and awe-inspiring to others. In that awe-inspiration, one finds the true motive and spring of all science; and in that horror, the spring and motive of all reforms in religion. For in admiring the magnitude, the symmetry, the beauty and the vastness of space and all it contains, we become curious and feel a sense of bold adventure, a gentle desire to discover still greater splendors, and sing their praises all our lives; and in our shock at the waste of our own lifetimes, and countless others before and alongside us, on any number of dead ends and useless victories, we become desperate and feel a sense of urgency, a fierce desire to discover another, better use for ourselves, and live by it to the end of our days. In that sense the astronomical endeavor, and the Exoplanet Survey in particular, is as much a universal enterprise psychologically as physically, and all the more, therefore, a source of wonder.