Morung Express Feature
In a discovery considered one of most significant on space exploration in recent times, the National Aeronautics and Space Administration (NASA) announced last week that its Spitzer Space Telescope has revealed the first known system of seven Earth-size planets around a single star.
“Three of these planets are firmly located in the habitable zone, the area around the parent star where a rocky planet is most likely to have liquid water,” NASA said in a statement.
The seven planets of TRAPPIST-1 are all Earth-sized and terrestrial, according to research published in 2017 in the journal Nature.
TRAPPIST-1 is an ultra-cool dwarf star in the constellation Aquarius, located about 40 light-years (235 trillion miles) from Earth. Because they are located outside of our solar system, these planets are scientifically known as exoplanets, NASA said.
The seven planets of TRAPPIST-1 are all Earth-sized and terrestrial. “They are likely all tidally locked, meaning the same face of the planet is always pointed at the star, as the same side of our moon is always pointed at Earth. This creates a perpetual night side and perpetual day side on each planet,” it said.
"The seven wonders of TRAPPIST-1 are the first Earth-size planets that have been found orbiting this kind of star," said Michael Gillon, lead author of the paper and the principal investigator of the TRAPPIST exoplanet survey at the University of Liege, Belgium.
For now, NASA has named them TRAPPIST-1b, c,d,e,f,g, and h. All of these seven planets could have liquid water – key to life as we know it – under the right atmospheric conditions, but the chances are highest with the three in the habitable zone, NASA said.
The system has been revealed through observations from NASA's Spitzer Space Telescope and the ground-based TRAPPIST (Transiting Planets and Planetesimals Small Telescope) telescope, as well as other ground-based observatories and sets a new record for greatest number of habitable-zone planets found around a single star outside our solar system.
The new results were published February 14 in the journal Nature, and announced at a news briefing at NASA Headquarters in Washington.
NASA invites names
While the NASA discovery of new exoplanets is creating a stirs among the scientific community and layman alike, it posting calling for their names on its Twitter account are generating humorous as well as well-meaning suggestions from the Twitterati .
For now NASA has temporarily named them - b, c, d, e, f, g and h- but it created a hash tag #7Namesfor7NewPlanets generating lot of buzz from online users and trended widely.
Some suggestion includes naming after Seven Dwarfs from a popular fairy tale to popular characters from Harry Potter to Star Trek series (Spock, McCoy, Scotty, Chekov, Sulu, Uhura) to writer like Asimov, Clarke, Wells, Orwell, Herbert, Bradbury, Verne; or naming them after movies.
Some even suggested the seven days of a week or the names of seven Kardashian sisters. It also assumed political colour when one user suggested their names as as "Far from Trump"- 1, 2, 3, 4, 5, 6 & 7.
The BBC reported that the exercise was mainly done to generate interest among the masses and creates awareness about space exploration.
According to NASA, the International Astronomical Union, which has the international authority for the naming of celestial objects, have started the process of adopting proper names for exoplanets.
Frequently asked question:
What is an exoplanet?
An exoplanet is a planet outside our solar system, usually orbiting another star. They are also sometimes called "extrasolar planets", "extra-" implying that they are outside of our solar system.
What are exoplanets made of?
The exoplanets for which astronomers are able to measure both their sizes (diameters) and masses, have densities that are suggestive of compositions ranging from very rocky (like Earth and Venus) to very gas-rich (like Jupiter and Saturn). Exoplanets are made up of elements similar to that of the planets in our solar system, but their mix of those elements may differ. Some planets may be dominated by water or ice, while others are dominated by iron or carbon.
How many exoplanets are there?
To date, more than 3,400 exoplanets have been discovered and considered "confirmed." However, there are over 2,000 other "candidate" exoplanet detections that require further observations in order to say for sure whether or not the exoplanet is real. Since the first exoplanets were discovered in the early 1990s, the number of known exoplanets has doubled approximately every 27 months.
What is the closest exoplanet?
Proxima Centauri b, which is about four light-years away. Its mass is consistent with it being slightly larger than Earth. Proxima Centauri b orbits in the "habitable zone" of its star, which means it could have liquid water on its surface– if it has an atmosphere which could support it. Its parent star, Proxima Centauri, is a dim red dwarf star that gives off about 600 times less light than our sun. Proxima Centauri is the closest star to the Earth after our sun, but it is still about 9,000 times further than planet Neptune.
How do we find exoplanets?
Most exoplanets are found through indirect methods: measuring the dimming of a star that happens to have a planet pass in front of it, or monitoring the spectrum of a star for the tell-tale signs of a planet pulling on its star and causing its light to subtly Doppler shift. NASA’s Kepler Space Telescope finds thousands of planets by observing “transits,” the slight dimming of light from a star when its tiny planet passes between it and our telescopes. Other methods include gravitational lensing, the “wobble method,” and direct imaging.
How many telescopes
are looking for exoplanets?
There are telescopes in space, on the ground, and even in the air that are being used to hunt exoplanets. NASA has three telescopes in space currently studying exoplanets– one observatory dedicated to discovering exoplanets (Kepler telescope), and two powerful, general-purpose observatories that conduct a wide range of astronomical observations, including exoplanet science (Hubble Space Telescope, Spitzer Space Telescope).
How do exoplanets get their names?
Exoplanet names can look long and complicated at first, especially in comparison to names like Venus and Mars. But they have a logic behind them that is important to scientists cataloging thousands of planets. Astronomers differentiate between the alphanumeric "designations" and alphabetical "proper names." All stars and exoplanets have designations, but very few have proper names. In recent years, the International Astronomical Union, the international authority for the naming of celestial objects, has started the process of adopting proper names for exoplanets. The first batch of named exoplanets came from a contest open to the public, and included about 15 stars and 20 exoplanets. From the contest, the first giant exoplanet discovered in 1995 (51 Peg b) was named "Dimidium" and its host star (51 Peg) "Helvetios."
(Source: With inputs from NASA Website)
