As 2017 comes to an end we look back at the amazing discoveries that have taken place this year. From strange exoplanetary systems to colliding neutron stars, space had a great deal to show us. Thus we start our first post in the annual Cosmic Rewind series to take look at all the breakthroughs, events and achievments that took place in the space field in 2017.
1. ISRO sets a world record
The Indian Space Research Organization or ISRO made headlines in February of 2017 when it made the world record for sending the largest number of space satellites (104) into orbit on a single rocket from Sriharikota. Out of the 104, 3 satellites were Indian while 101 of these satellites were foreign from countries like Isreal, Kazakhstan, Netherlands, United Arab Emirates and the USA.
The mission broke the previously held record of Russia of sending 37 satellites on one rocket by a whopping 67!! The mission was conducted using the Polar Satellite Launch Vehicle or PSLV which is shown below.
This achievment showed the capablities of India in the field of space exploration, to the world and promised many more contributions by the agency in the future.
2. The TRAPPIST-1 planetary system
Again in February of 2017, a few days after ISRO’s feat, the discovery of seven planets around a red dwarf star called TRAPPIST-1 hit headlines. The excitement among the space community was due to the fact that all the seven planets were rocky in nature, which means they all had a solid surface. Moreover, three of them were deemed to be habitable as they lied in the habitable zone of their host star.
TRAPPIST-1 is a red dwarf star that lies 39.6 light years away in the constellation of Aquarius. As any red dwarf star, TRAPPIST-1 is subject to a lot of flaring activity which can expose the potential life on the 3 habitable planets to high levels of radiation. Thus this means a bad news for life.
However it is still an interesting prospect that there could be 3 habitable planets with life on it in a relativly nearby star system. This discovery shatters the long held notion that Earth is special and rare.
Here is an artist’s impression of the appearances of each of the TRAPPIST-1 exoplanets. TRAPPIST-1d, e, f are the habitable planets.
3. Potential life on Enceladus
While scientists were finding life outside the Solar System, the Cassini probe made an important and exciting discovery of hydrogen on Enceladus in April of 2017. Enceladus, a moon of Saturn was long known to contain a subsurface ocean of liquid water. Although presence of life is not yet confirmed, the discovery of hydrogen plumes by Cassini marked the discovery of the final ingredient of life on the Saturnian moon.
Although Enceladus had a water ocean beneath its icy surface, an energy source for life was unknown until the discovery of molecular hydrogen. Molecular hydrogen plays an important role in providing energy for life processes in harsh environments. Geysers on Enceladus’ surface spew out the content beneath the ice and Cassini flew through them and found molecular hydrogen. This is shown in artist’s rendition below.
However, the discovery of the key ingredient of life does not mean the discovery of life itself. Future missions to Enceladus which inculde ideas like drilling though the ice might answer the question.
4. The Great American Eclipse of 2017
As far as eclipses go, 2017 had a great deal to show us. On August 21, 2017 a total solar eclipse was visible from the US and was dubbed the Great American Eclipse. It was one of the most viewed, photographed, televised and discussed event in a generation. The path of totality ran from the middle of the North Pacific Ocean and across 14 American states from West to East giving, millions a chance to see the spectacle. The event ended over 300 miles from Cape Verde.
This was the first total solar eclipse in America since World War 1.
The above image shows the corona or the atmosphere of the Sun which was visible during the event. The corona is normally not visible due to the extreme brightness of the Sun.
5. Cassini’s Grand Finale
As the year moved by the arrival of September, something sad happened in the space community. NASA’s Cassini spacecraft we talked about earlier was running out of fuel and hence coud’nt be used much longer. Moreover there were tantalizing evidences that life might exist on Enceladus, one of Saturn’s moons. Thus there was a risk that the probe might crash into the moon and contaminate it with Earth bacteria.
Thus to prevent such a thing from happening, NASA decided to take the plunge and send the probe crashing into Saturn’s atmosphere. What was so heartbreaking about this was that Cassini had studied Saturn for 13 years following its arrival on the planet on July 1, 2004.
It was launched on October 15, 1997 making a total of 20 years in space. It had taught us a lot about the Saturnian system which included the existence of Titan’s methane atmosphere, hexagonal storms at Saturn’s north pole, hydrogen plumes on Enceladus and so on. Now, it was time to say goodbye.
The probe kept on transmitting information until the very last minute before it was torn apart by Saturn’s atmosphere. On the bright side, we still have terabytes of unanalyzed data from Cassini waiting to be studied. Who knows what new discoveries that might bring?
The kilonova explosion which was detected on August of 2017 was undoubtedly the biggest breakthrough in astrophysics that occured in 2017. However the results of the observation were only released in October.
To brief up a bit a kilonova is an explosion that occurs with the merger of two neutron stars. In August the Laser Interferometry Gravitaional wave Observatory or LIGO detected gravitational waves for the 5th time. But the speciality of this detection was due to the fact that unlike other detections, the source of gravitational waves was due to the merger of two neutron stars (unlike the collision of two black holes) 130 million light years away.
This event was further observed by over 100 instruments over 70 telescopes with a collaboration of 3500 astronomers making it the first cosmic event to be observed in gravitational waves as well as optical wavelengths. The Fermi satellite also observed gamma rays coming from the direction of the event.
The detection brought with it, answers to several questions which were considered mysteries. For example, it showed us the origin of heavier elements like gold or platinum which coud’nt be generated by fusion processes in stars. It also explained the origin of gamma ray bursts and confirmed Einstein’s Theory of Relativity yet again. Further insights into cosmology and nuclear physics were also made by this detection.
7. Arrival of the interstellar messenger
October was 2017’s hub for exciting space discoveries. Within a week of the announcement of the kilonova, an object was discovered which had come from outer space. Enter Oumuamua. On October 19, 2017 Robert Werrick discovered an object which did not appear to originate in the Solar System. Given below is an artist’s impression of Oumuamua.
Orignally designated as 1I/2017 U1, this object came from above the plane of the Solar System and is now on its way out never to return. What was so interesting about this discovery was that now scientists could study the working of other star systems without actually having to go there. Moreover this object was elongated like a cigar which was unusual for an asteroid or comet.
Unfortunately Oumuamua is on its way out of the Solar System at an incredibly high speed of 26 km/s. Even humanity’s fastest probe, New Horizons and Voyager travel at a mere 17 km/s. However, proposed mission concepts like laser driven sails and nano craft do seem promising.
8. Closer to Earth 2.0?
And last but not the least as the year comes to an end, our search for the second Earth drew more promising results. We have Ross 128b an exoplanet just 11 light years away which could harbour alien life!!
The discovery of Proxima b, last year gave the same promise of life but later observations showed it was subject to lot of radiation from its parent star aka Proxima Centauri. However Ross 128b orbits a relatively calm star like our Sun called Ross 128. Moreover, the planet lies in the star’s habitable zone and could have liquid water on its surface.
This is an artist’s impression of Ross 128b, an Earth like world which might harbour life and liquid water.
This discovery is a major step to find the elusive Earth 2.0. On a side note, scientists discovered strange radio signals coming from the direction of Ross 128. However these signals can also have a natural explanation and are not a strong sign of alien life. Who knows, perhaps a strange slimy creature might be exiting the pool of water and breathing fresh air on Ross 128b as you read!!
With that 2017 comes to an end, and marks the beginning of the New Year 2018 with many more promises of breakthroughs and achievements in the field of astronomy, astrophysics and science!! Lets hope man’s desire to understand this place we call the Universe is fulfilled in the years to come.
Happy New Year!!