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24 February 2017 Editorial

 

24 FEBRUARY 2017 

Life elsewhere

UPDATED: FEBRUARY 24, 2017 00:24 IST

The quest to find life outside the solar system got a big boost with the discovery of seven Earth-size extra-solar planets, or exoplanets, orbiting a dwarf star about 40 light years away. Unlike earlier discoveries of exoplanets, all seven planets could possibly have liquid water — a key to life as we know it on Earth — with three planets having the greatest chance. This is by far the largest collection of Earth-like planets in the habitable ‘Goldilocks’ zone of a starneither too close nor too far from a star, which raises the possibility of liquid water being present on the surface. Only Earth has liquid water in the solar system. Less than a year after scientists announced the discovery of three planets orbiting the dwarf star, the team found four more through intense searches using several ground-based telescopes, including a 20-day continuous monitoring using the U.S. National Aeronautics and Space Administration’s Spitzer Space Telescope. Since the dwarf star is much cooler than the Sun, the dimming of light each time a planet passes or transits before the star could be easily recorded from Earth unlike in cases when planets transit a Sun-like bright star. Since the initial discovery of three planets was made using the Chile-based Transiting Planets and Planetesimals Small Telescope, the exoplanet system is called TRAPPIST-1. Unlike in the case of our solar system, the planets have apparently formed far away from the star and gradually migrated towards it; they share a similar formation history with the Galilean moons, which migrated towards Jupiter after formation. Another major difference in comparison with the solar system is the tight packing of the seven planets around the star. The closest planet in the TRAPPIST-1 system takes just 1.5 days to complete an orbit and the farthest one takes 20 days; the orbital period of the planets is also similar to the Galilean moons.

With a fair possibility of liquid water being present on at least three planets, the focus is now on deciphering the climate and chemical composition of their atmosphere. As a first measure, scientists are keen to know if the planets are Earth-like, by ruling out the presence of hydrogen gas enveloping them. Mass estimates already suggest that the inner six planets might have a rocky composition, while the one with a low density may have a volatile composition due to the presence of an ice layer or atmosphere. The composition of the atmosphere can be identified by measuring the wavelength characteristics of light. Since the TRAPPIST-1 system is close by and the star is cool enough, it would be easier to decipher the various critical features of the planets. If there is life on these planets, we would know this in about 10 years. The search for extraterrestrial life has just become more focussed.

Goldilocks Zone

 

  •   Our planet occupies what scientists sometimes call the Goldilocks zone. Its distance from our star means it is neither too hot, nor too cold to support liquid water - thought to be a key ingredient for life.
  •  Astronomers are searching for rocky planets like ours in the Goldilocks zones of other stars.


 

 

Campus chill

A very uneasy calm was restored to the Delhi University’s North campus, with anxiety still gripping colleges and hostels after two days of violence. Trouble started on Tuesday when members of the Akhil Bharatiya Vidyarthi Parishad, the student organisation linked to the BJP, stormed Ramjas College to disrupt a seminar titled “Cultures of Protest” organised by its English department and the literary society. They focussed attention on the participation of Umar Khalid, a student leader from Jawaharlal Nehru University (JNU) who had been controversially booked for sedition last year in a particularly fraught ideological stand-off between the establishment and the left-leaning JNU. They forced the cancellation of not just his session at Ramjas College but also what remained of the two-day event. A day later, as a protest against the incident was organised on the DU campus, ABVP members again arrived at the gates of Ramjas College to prevent students from participating in the march. In no time, clashes erupted, with students of the college alleging violence by the ABVP members and a hands-off response from the Delhi Police. Student politics in DU has often been edgy, but this week’s events mark a dark and worrying turn. Fearing trouble, many students associated with the anti-ABVP protest who live around the campus left to stay elsewhere. Students are mobilising to demand that the first information report make a distinction between those who disrupted the seminar and those rallying in its defence. But the most grave consequence is the message that is being sent out about the possibility of free debate.

Umar Khalid was to have spoken in a session on “Unveiling the state: Regions in conflict — the war in Adivasi areas”, reportedly based on his research on Bastar. It was part of a programme cleared by the college authorities. If they are so quickly intimidated into cancelling the seminar, if the police do not rally sufficiently to protect debate on the campus, the signal goes out that students and faculty are on their own in defending the right to free debate. The Ramjas College incident also comes a year after the events at JNU when the ABVP led the Sangh’s charge against what they deemed to be “anti-national”. Then too an impression was created that the police were too easily led to heed the ABVP’s agenda; the reverberations of that episode are still being felt. Universities are arenas for intellectual evolution, they are meant to be spaces where discussion and debate push boundaries, where students learn not only the art of provocation but also the argumentative skills to defend and oppose such provocation. Certainly, there are necessary curbs such as a bar on speech that incites violence and hate. But when a students’ organisation uses violence to have a seminar cancelled, and when the authorities succumb so easily, Indian academia stands diminished.

 

 

 

 

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