This Day in History (18-Feb-1930) – Clyde Tombaugh Discovers Pluto

Looking over some photographic plates from the month before as part of his research into asteroids, astronomer Clyde Tombaugh noticed a peculiar object on February 18, 1930: the ‘Planet X’. Part of a larger cloud of debris called the Kuiper belt, the small orb 4.6 billion miles from the sun has become a controversial figure in the scientific community. Lurking among the distant rocks sprayed across space beyond the orbits of Uranus and Neptune, Percival Lowell — the founder of the observatory Tombaugh worked at — first theorized the presence of a “Planet X” affecting the two outermost planets and predicted its location in 1909. Tombaugh carried on the research after Lowell’s death and diligently spent each day taking photographs of the night sky and looking them over with a blink comparator, an optical device that allows the researcher to quickly flip back and forth between two images.

The news shocked the public, resulting in a flood of more than a thousand letters arriving at the Lowell Observatory with ideas for naming the planet. Venetia Burnley, an 11-year-old girl from the English city of Oxford, suggested Pluto, Roman name for the Greek god of the underworld, Hades (world of deads). Taking 248 Earth years to make one pass around the sun, Pluto’s orbit does not fit the regular pattern exhibited by the other eight planets. At times, it is within the path trotted by Neptune, a factor in debates about the true status of the object.

Following more than 75 years of being regarded as a planet, the International Astronomical Union announced Pluto no longer fit the bill in August 2006. Citing the shape of its orbit and the various asteroids it shares the Kuiper belt with, experts decided to downgrade it to a dwarf planet. (True planets have to “own” their path around the sun.)

There are now officially only eight planets in our solar system. Pluto  is much smaller than any of the official planets. It is smaller than seven of the solar system’s moons including moon of the earth. Pluto has not yet been visited by a spacecraft. Even the Hubble Space Telescope can resolve only the largest features on its surface (left and above). A spacecraft called New Horizons was launched in January 2006. If all goes well it should reach Pluto in 2015.


This Day in History (13-Feb-1633) – Galileo Galilei arrives in Rome for trial after publishing his thoughts on heliocentrism

Galileo used his mathematics knowledge and technical skills to  build a telescope in 1609.  Galileo’s observations strengthened his belief in Copernicus’ theory (published in 1514)that Earth and all other planets revolve around the Sun. Galileo expected the telescope to quickly make believers in the Copernican system out of all educated persons, but he was disappointed. The Catholic Church, which was very powerful and influential in Galileo’s day, strongly supported the theory of a geocentric, or Earth-centered, universe. In 1616, on orders of the Pope Paul V, Cardinal Bellarmine called Galileo to his residence and administered a warning not to hold or defend the Copernican theory; Galileo was also forbidden to discuss the theory orally or in writing. After repeated convincing attempts by Galileo, Pope Urban VIII allowed him to write about the Copernican theory as long as he treated it as a mathematical hypothesis.

In 1630 he completed his book Dialogue Concerning the Two Chief World Systems in which the Ptolemaic and Copernican models were discussed and compared. Vatican cleared (conditionally) to publish the book. The book was printed in 1632 which was quickly sold out and soon became the talk of the literary public. Enemies of Galileo had convinced the Pope that the Dialogue was nothing but a thinly-veiled brief for the Copernican model. Pope Urban VIII, convinced by the arguments of various Church officials, stopped its distribution; the case was referred to the Inquisition and Galileo was summoned to Rome despite his infirmities, to answer the charges in February 1633. Old Galileo travelled for twenty-three days in cold winter from Florence to Rome.

He was formally interrogated for 18 days and on April 30 Galileo confessed that he may have made the Copernican case in the Dialogue too strong and offered to refute it in his next book.  Galileo was sentenced to life imprisonment. Because of his age and poor health, he was allowed to serve his imprisonment under house arrest until his death in 1642. The Church finally accepted that Galileo might be right in 1983.



This Day in History (28-Jan-1986) – Challenger explodes

The space shuttle Challenger was one of NASA’s greatest triumphs. It was the second shuttle to reach space, in April 1983. It successfully completed nine milestone missions. Challenger was the vehicle by which several cultural firsts happened in the space shuttle program. The first American female astronautrode up on Challenger on STS-7 in June 1983.  The first African-American reached space on STS-8. On STS-41G in 1984, two women, flew on one mission for the first time, as well as the first Canadian, Marc Garneau. Other milestones Challenger marked included the first night launch and landing (STS-8) and the first operational Spacelab flight (STS-51B).

Christa McAuliffe, a 37-year-old high school social studies teacher from New Hampshire, won a competition that earned her a place among the seven-member crew of the Challenger’s tenth mission. She underwent months of shuttle training but then, beginning January 23, was forced to wait six long days as the Challenger’s launch countdown was repeatedly delayed because of weather and technical problems. Finally, on January 28, Challenger was launched at 11:38 a.m. Eastern time in front of more media attention than usual, as it was carrying the first teacher to go in space. Seventy-three seconds later, hundreds on the ground, including Christa’s family, stared in disbelief as the shuttle exploded in a forking plume of smoke and fire. Millions more watched the wrenching tragedy unfold on live television. There were no survivors.  President Ronald Reagan appointed a special commission headed by former secretary of state William Rogers and former astronaut Neil Armstrong. The investigation determined that the explosion was caused by the failure of an “O-ring” seal in one of the two solid-fuel rockets. The elastic O-ring did not respond as expected because of the cold temperature at launch time, which began a chain of events that resulted in the massive explosion.

Challenger’s explosion changed the space shuttle program in several ways. Plans to fly other civilians in space (such as journalists) were shelved for 22 years. Satellite launches were shifted from the shuttle to reusable rockets. On February 1, 2003, a second space-shuttle disaster rocked when Columbia disintegrated upon reentry of the Earth’s atmosphere. All aboard were killed including the first Indian-American astronaut and first Indian woman in space, Kalpana Chawla.


This Day in History (22-Oct-2008) – India’s first unmanned lunar mission, Chandrayaan-1, was launched

The idea of undertaking an Indian scientific mission to Moon was initially mooted in a meeting of the Indian Academy of Sciences in 1999 that was followed up by discussions in the Astronautical Society of India in 2000. Based on the recommendations made by the learned members of these forums, a National Lunar Mission Task Force was constituted by the Indian Space Research Organisation (ISRO). Subsequently, Government of India approved ISRO’s proposal for the first Indian Moon Mission, called Chandrayaan-1 in 2003.

On 22nd October 2008, At 6:22 a.m., the Polar Satellite Launch Vehicle (PSLV)-XL rocket shot into a dark sky; the four stages ignited and fell away on time. About 18 minutes and 20 seconds after take-off, the rocket’s fourth stage injected Chandrayaan-1 into its initial orbit at a velocity of 9.25 km a second. The Rs. 400 crore mission, a significant milestone in India’s space programme, included a lunar orbiter and an impactor. The remote sensing lunar satellite, with a mass of 1,380 kg at launch and 675 kg in lunar orbit, carried high-resolution equipment.

Seventeen days after the launch, the vehicle was successfully inserted into the lunar orbit. The Moon Impact Probe separated from the Chandrayaan orbiter on November 14, 2008 and struck the south pole, making India join a very select group of nations that have their flags on the Moon. After hitting the surface near a crater, it ejected underground soil, which was then tested for the presence of lunar water ice.

Around nine months after the Chandrayaan launch, there was a glitch in the satellite’s ‘star sensors’. Eventually, the mission was declared over on 29 August after Chandrayaan stopped sending radio signals. Though it operated for 312 days instead of the planned two years, the mission achieved 95 percent of its planned objectives, ISRO said. Among other achievements, the mineral content on the lunar surface was mapped with the Moon Mineralogy Mapper; the changes in rock and mineral composition were identified; the Oriental Basin region of the Moon was mapped; and mapping of the Moon missions landing sites was carried out.



This Day in History (5-Oct-1997) – Dr. Kalpana Chawla became the first Indian woman to become an astronaut

Born in Karnal, India, Kalpana Chawla obtained a degree in aeronautical engineering from Punjab Engineering College before immigrating to the United States and becoming a naturalized citizen in the 1980s. She earned a doctorate in aerospace engineering from the University of Colorado in 1988, having previously obtained her masters degree from the University of Texas. She began working at NASA’s Ames Research Center the same year, working on power-lift computational fluid dynamics.

In 1994, Chawla was selected as an astronaut candidate. After a year of training, she became a crew representative for the Astronaut Office EVA/Robotics and Computer Branches, where she worked with Robotic Situational Awareness Displays and tested software for the space shuttles. Chawla’s first opportunity to fly in space came in November 1997, aboard the space shuttle Columbia on flight STS-87. The shuttle made 252 orbits of the Earth in just over two weeks. The shuttle carried a number of experiments and observing tools on its trip, including a Spartan satellite, which Chawla deployed from the shuttle.

In 2000, Chawla was selected for her second voyage into space, serving again as a mission specialist on STS-107. The mission was delayed several times, and finally launched in 2003. Over the course of the 16-day flight, the crew completed more than 80 experiments. On the morning of Feb. 1, 2003, the space shuttle returned to Earth. At launch, a piece of insulation had broken off and damaged the thermal protection system of the shuttle’s wing, the shield that protects it from heat during re-entry. As the shuttle passed through the atmosphere, hot gas streaming into the wing caused it to break up. The unstable craft rolled and bucked, pitching the astronauts about and got depressurized, killing the crew.

Over the course of her two missions, Chawla logged 30 days, 14 hours, and 54 minutes in space. After her first launch, she said, “When you look at the stars and the galaxy, you feel that you are not just from any particular piece of land, but from the solar system.”


This Day in History (4-Oct-1957) – The Soviet Union launches Sputnik 1 into space

History changed on October 4, 1957, when the Soviet Union successfully launched Sputnik I. The world’s first artificial satellite was about the size of a beach ball (58 cm. in diameter), weighed only 83.6 kg, and took about 98 minutes to orbit the Earth on its elliptical path. That launch ushered in new political, military, technological, and scientific developments. While the Sputnik launch was a single event, it marked the start of the space age and the U.S.-U.S.S.R space race.

The story begins in 1952, when the International Council of Scientific Unions decided to establish July 1, 1957, to December 31, 1958, as the International Geophysical Year (IGY) because the scientists knew that the cycles of solar activity would be at a high point then. In October 1954, the council adopted a resolution calling for artificial satellites to be launched during the IGY to map the Earth’s surface. In July 1955, USA announced plans to launch an Earth-orbiting satellite for the IGY and solicited proposals from various Government research agencies to undertake development. In September 1955, the Naval Research Laboratory’s Vanguard proposal was chosen to represent the U.S. during the IGY.

However the Sputnik launch changed everything. As a technical achievement, Sputnik caught the world’s attention and the American public off-guard. Its size was more impressive than Vanguard’s intended 3.5-pound payload. In addition, the public feared that the Soviets’ ability to launch satellites also translated into the capability to launch ballistic missiles that could carry nuclear weapons from Europe to the U.S. Then the Soviets struck again; on November 3, Sputnik II was launched, carrying a much heavier payload, including a dog named Laika.

The Sputnik launch also led directly to the creation of National Aeronautics and Space Administration (NASA). In July 1958, US Congress passed the National Aeronautics and Space Act (commonly called the “Space Act”), which created NASA as of October 1, 1958 from the National Advisory Committee for Aeronautics (NACA) and other government agencies.



This Day in History (23-Sep-1846) – Astronomers Discover Neptune

After first being sighted in the night sky by Galileo in 1612, it took well over two centuries for scientists to determine the bright object near Jupiter in the famous Italian’s notes was not a star.  Urbain Le Verrier and Johann Gottfried Galle, working together on the European continent, and John Couch Adams, making calculations independently in England, learned the heavenly body was actually the planet Neptune on September 23, 1846.

Alexis Bouvard, attempting to determine the orbits of the planets in 1821, realized the planet Uranus seemed to be swayed and theorized another large object nearby might be affecting it. Two decades later, Adams focused his energies on the same issue.  Unsatisfied with the limited data he had managed to gather, he made an inquiry with the Astronomer Royal, George Airy, in search of more information to help him with his search for a new planet.  Upon receiving a large number of observations in February 1844, he spent two-and-a-half years attempting to determine where this unknown celestial body might be.

At the same time, Le Verrier focused his attention on determining what Bouvard had found.  Unable to muster much in the way of interest, he published a series of estimates in June 1846.  Le Verrier, struggling to find scientists in his own country willing to pay attention and collaborate, wrote a letter to Galle at the Berlin Observatory detailing his findings.  Arriving on the morning of September 23, 1846, Le Verrier’s note proved to be the final catalyst to the discovery of Neptune.  After nightfall, Galle located the planet just one degree away from where Le Verrier had predicted it would be and 12 degrees away from Adams’ calculated location.  The eighth planet in Earth’s solar system had been officially discovered. After the discovery, there was rivalry between England and France about who should get credit for finding Neptune, Adams or Le Verrier. The international astronomy community agreed that the two astronomers should share credit for the discovery.

Late in 1846, the St. Petersburg Academy of Sciences pushed Le Verrier’s first suggestion for name — Neptune — to the fore.  Honoring the Roman god of the sea, it remains the farthest planet from the sun.