Category The Universe, Exploring the Universe, Solar System, The Moon, Space, Space Travel

On October 18, 2019, NASA astronauts Christina Koch and Jessica Meir created history by completing the first-ever all-female spacewalk. The astronauts stepped outside the International Space Station and replaced a battery discharge unit that failed to activate after new lithium-ion batteries were installed on the station’s exterior structure. The historic moment was originally supposed to occur in March that year, but the event was postponed due to lack of spacesuits for women. Still, the first all-woman spacewalk is a milestone worth celebrating as the agency looks forward to putting the first woman on the Moon by 2024 with its Artemis lunar exploration programme.

Today marks Koch’s fourth spacewalk and Meir’s first spacewalk. Koch led the EVA and can be identified by the red stripes on her spacesuit and life support backpack. Meir arrived at the space station in September, and both Koch and Meir joined NASA’s astronaut corps in 2013. Their astronaut class, nicknamed the “Eight Balls,” had the highest percentage of women of any group of astronaut candidates to date.

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Scientist released the first-ever image of a black hole, captured by the Event Horizon Telescope, a network of eight linked telescopes on April 10, 2019. This could safely be called the biggest scientific feat of the decade. Before this, every image of a black hole we saw online or in print was an illustration. This image is a direct proof of the existence of black holes. The fuzzy doughnut-shaped ring of gas and dust traces the outline of a supermassive black hole at the heart of the Messier 87 galaxy, 55 million light years from Earth. With a mass 6.5 billion times that of the Sun; it is a humongous black hole.

Black holes are regions in space, where the gravity is so immense that even light cannot escape from their grasp. The boundary around the mouth of the black hole beyond which nothing can escape is called event horizon. It traps everything that comes to this point.

Black holes are formed when giant stars explode at the end of their life-cycle. This explosion is called a supernova. When a star collapse under its own weight, it results in the concentration of a huge amount of mass densely packed in an incredibly small area. Think of a star ten times more massive than the Sun squeezed into a sphere approximately the diameter of Bengaluru. The region is so dense that it warps the fabric of space and time.

Black holes can grow huge as they continue to attract light, dust and gas around them. They can even absorb other stars.

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On November 15, 2018 NASA, officially bid farewell to its iconic planet hunter, the Kepler Space Telescope, as it ran of fuel. Peering into deep space, the observatory discovered as many as 2,662 exoplanets in just nine years. The Kepler Space Telescope was launched in 2009 to find out how many earth-sized planets are there in the habitable zones of other stars in the Milky-way. Kepler hunted planets in a surprisingly straightforward manner. By fixating on a specific area of the sky in the constellation Cygnus, Kepler was able to continuously monitor the varying brightnesses of roughly 150,000 stars.

Although Kepler is now retired, its successor, the Transiting Exoplanet Survey Satellite (TESS) has already begun operation. Launched on April 18, 2018, TESS carries forward Kepler’s planet-hunting legacy by searching for exoplanets around nearly 200,000 of the brightest and nearest stars to Earth.

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On August 12, 2018, NASA’s Parker Solar Probe was launched with the mission of repeatedly probing and making observations of the outer corona of the Sun. On October 29, 2018, the spacecraft became the closest ever artificial object to the Sun. Its trajectory includes seven Venus flybys over nearly seven years to gradually shrink its elliptical orbit around the Sun. The spacecraft will undertake 24 orbits around the Sun. With this mission, scientists seeks to solve two long-standing puzzles; how the stream of particles flowing continuously from the sun, known as the solar wind, is accelerated to its tremendous velocities; and why the sun’s outer atmosphere, or corona, is so much hotter than its surface.

Parker Solar Probe will use seven Venus flybys over nearly seven years to gradually shrink its orbit around the Sun, coming as close as 3.83 million miles (and 6.16 million kilometers) to the Sun, well within the orbit of Mercury and about seven times closer than any spacecraft has come before.

Parker Solar Probe is a true mission of exploration; for example, the spacecraft will go close enough to the Sun to watch the solar wind speed up from subsonic to supersonic, and it will fly through the birthplace of the highest-energy solar particles.

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On October 19, 2017, Scientists detected the first known alien visitor, named Oumuamua, passing through our Solar System. It was about 33 million km from Earth (about 85 times as far away as the Moon), and already heading away from the Sun. The interstellar object was relatively flat and cigar-shaped. Astonomers aren’t exactly sure where it came from, or really even what it is. However, in July 2019, astronomers reported that Oumuamua was an object of a purely natural origin. (Oumuamua in Hawaiian means “scout” or “visitor from after arriving first”.)

The Spitzer Space Telescope did not detect any heat in the form of infrared radiation from ‘Oumuamua. Given the surface temperature dictated by ‘Oumuamua’s trajectory near the sun, this sets an upper limit on its size of hundreds of meters. Based on this size limit, ‘Oumuamua must be unusually shiny, with a reflectance that is at least 10 times higher than exhibited by solar system asteroids.

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NASA’s Cassini spacecraft made a fateful plunge into the atmosphere of Saturn, ending its 13-year tour on September 15, 2017. Cassini was launched in 1997 to orbit and observe the ringed planet and its many moons. The spacecraft arrived at Saturn in 2004. NASA extended its mission twice – first for two years, and then for seven more. The second mission extension saw dozens of flybys of the planet’s icy moons, using the spacecraft’s remaining rocket propellant along the way. Cassini discovered half a dozen moons, geysers on Enceladus and lakes on Titan.

During planning for its extended missions, various future plans for Cassini were evaluated on the basis of scientific value, cost, and time. Some of the options examined included collision with Saturn atmosphere, an icy satellite, or rings; another was departure from Saturn orbit to Jupiter, Uranus, Neptune, or a centaur. Other options included leaving it in certain stable orbits around Saturn, or departure to a heliocentric orbit. Each plan required certain amounts of time and changes in velocity.

Scientific data was collected using eight of its twelve science instruments. All of the probe’s magnetosphere and plasma science instruments, plus the spacecraft’s radio science system, and its infrared and ultraviolet spectrometers collected data during the final plunge. The data rates flowing back from Saturn could not support imaging during the final plunge, so all pictures were down linked (transmitted back to Earth) and cameras were switched off, before the final plunge began. The predicted altitude for loss of signal was approximately 1,500 km (930 mi) above Saturn’s cloud tops, when the spacecraft began to tumble and burn up like a meteor.

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