My Science School

Apollo 14 launched in the late afternoon of January 31, 1971 on what was to be our third trip to the lunar surface. Five days later Alan Shepard and Edgar Mitchell walked on the Moon while Stuart Roosa, a former U.S. Forest Service smoke jumper, orbited above in the command module. Packed in small containers in Roosa's personal kit were hundreds of tree seeds, part of a joint NASA/USFS project. Upon return to Earth, the seeds were germinated by the Forest Service. Known as the "Moon Trees", the resulting seedlings were planted throughout the United States (often as part of the nation's bicentennial in 1976) and the world. They stand as a tribute to astronaut Roosa and the Apollo program.

Stan Krugman collected the seeds and an attempt at germinating some of the seeds was made in Houston. Somewhat surprisingly, it proved successful and the seeds started growing, but they did not survive long because the facilities there were inadequate. A year later the remaining seeds were sent to the southern Forest Service station in Gulfport, Mississippi (sycamore, loblolly pine, and sweetgum) and to the western station in Placerville, California (redwood and Douglas fir) to attempt germination. Many of the seeds, and later cuttings, were successful and grew into viable seedlings. Some of these were planted with their Earth-bound counterparts as controls, (as might be expected, after over forty years there is no discernable difference) but most were given away in 1975 and 1976 to many state forestry organizations to be planted as part of the nation's bicentennial celebration. These trees were southern and western species, so not all states received trees. A loblolly pine was planted at the White House, and trees were planted in Brazil, Switzerland, and presented to the Emperor of Japan, among others. Trees have also been planted in Washington Square in Philadelphia, at Valley Forge, in the International Forest of Friendship, and at various universities and NASA centers. 

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The first vegetable grown and eaten on the International Space Station space was Outredgeous red romaine lettuce, in 2015. Bred by Frank Morton of Wild Garden Seed. 64 days to maturity on earth, 33 days in space, with intensely dark red, slightly ruffled leaves forming loose upright heads. 

The Veggie system was developed by Orbital Technologies Corp. (ORBITEC) in Madison, Wisconsin, and tested at Kennedy before flight. Veggie, along with two sets of pillows containing the romaine seeds and one set of zinnias, was delivered to the station on the third cargo resupply mission by SpaceX in April 2014.

The collapsible and expandable Veggie unit features a flat panel light bank that includes red, blue and green LEDs for plant growth and crew observation. Using LED lights to grow plants was an idea that originated with NASA as far back as the late 1990s, according to Dr. Ray Wheeler, lead for Advanced Life Support activities in the Exploration Research and Technology Programs Office at Kennedy.

Wheeler worked with engineers and collaborators to help develop the Veggie unit from a Small Business Innovative Research project with ORBITEC. Dr. Gioia Massa is the NASA payload scientist for Veggie at Kennedy. Massa and others worked to get the flight unit developed and certified for use on the space station. The purple/pinkish hue surrounding the plants in Veggie is the result of a combination of the red and blue lights, which by design emit more light than the green LEDs. Green LEDS were added so the plants look like edible food rather than weird purple plants.

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In 1982, the crew of the Soviet Salyut 7 space station conducted an experiment, prepared by Lithuanian scientists (Alfonsas Merkys and others), and grew some Arabidopsis using Fiton-3 experimental micro-greenhouse apparatus, thus becoming the first plants to flower and produce seeds in space.

Plant research continued on the International Space Station. Biomass Production System was used on the ISS Expedition 4. The Vegetable Production System (Veggie) system was later used aboard ISS. Plants tested in Veggie before going into space included lettuce, Swiss chard, radishes, Chinese cabbage and peas. Red Romaine lettuce was grown in space on Expedition 40 which were harvested when mature, frozen and tested back on Earth. Expedition 44 members became the first American astronauts to eat plants grown in space on 10 August 2015, when their crop of Red Romaine was harvested. Since 2003 Russian cosmonauts have been eating half of their crop while the other half goes towards further research. In 2012, a sunflower bloomed aboard the ISS under the care of NASA astronaut Donald Pettit. In January 2016, US astronauts announced that a zinnia had blossomed aboard the ISS.

In 2017 the Advanced Plant Habitat was designed for ISS, which was a nearly self-sustaining plant growth system for that space station in low Earth orbit. The system is installed in parallel with another plant grown system aboard the station, VEGGIE, and a major difference with that system is that APH is designed to need less upkeep by humans. APH is supported by the Plant Habitat Avionics Real-Time Manager. Some plants that were to be tested in APH include Dwarf Wheat and Arabidopsis. In December 2017 hundreds of seeds were delivered to ISS for growth in the VEGGIE system.

In 2018 the Veggie-3 experiment at the ISS, was tested with plant pillows and root mats. One of the goals is to grow food for crew consumption. Crops tested at this time include cabbage, lettuce, and mizuna. In 2018, the PONDS system for nutrient deliver in microgravity was tested.

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Plant Habitat (APH) abroad the International Space Station in 2020?

NASA astronaut Kate Rubins harvested fresh radishes grown in space, opening new doors for producing food in microgravity to sustain future longer-term missions to the moon and Mars.

The radishes were grown in the Advanced Plant Habitat (APH) aboard the International Space Station. NASA shared a time-lapse video of the radishes as they grew inside the APH over the course of 27 days. 

Radishes are the latest type of fresh produce to be successfully grown and harvested in microgravity, and were chosen for the Plant Habitat-02 (PH-02) experiment because the vegetable is well understood by scientists and reaches maturity in just 27 days. 

Radishes are also a viable test plant for future longer-term missions because they are edible and nutritious. The vegetable is genetically similar to Arabidopsis, which is a small flowering plant related to cabbage that has been studied frequently in microgravity, according to the NASA statement. 

Credit : Space.com

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Neutron stars can rotate up to at least 60 times per second when born. If they are part of a binary system, they can increase this rotation rate through the accretion of material, to over 600 times per second! 

Neutron stars pack their mass inside a 20-kilometer (12.4 miles) diameter. They are so dense that a single teaspoon would weigh a billion tons — assuming you somehow managed to snag a sample without being captured by the body's strong gravitational pull. On average, gravity on a neutron star is 2 billion times stronger than gravity on Earth. In fact, it's strong enough to significantly bend radiation from the star in a process known as gravitational lensing, allowing astronomers to see some of the back side of the star.

The power from the supernova that birthed it gives the star an extremely quick rotation, causing it to spin several times in a second. Neutron stars can spin as fast as 43,000 times per minute, gradually slowing over time.

If a neutron star is part of a binary system that survived the deadly blast from its supernova (or if it captured a passing companion), things can get even more interesting. If the second star is less massive than the sun, it pulls mass from its companion into a Roche lobe, a balloon-like cloud of material that orbits the neutron star. Companion stars up to 10 times the sun's mass create similar mass transfers that are more unstable and don't last as long.

Stars more than 10 times as massive as the sun transfer material in the form of stellar wind. The material flows along the magnetic poles of the neutron star, creating X-ray pulsations as it is heated.

By 2010, approximately 1,800 pulsars had been identified through radio detection, with another 70 found by gamma-rays. Some pulsars even have planets orbiting them — and some may turn into planets.

Credit : Space.com

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Halley is the only known short-period comet that is regularly visible to the naked eye from Earth, and thus the only naked-eye comet that can appear twice in a human lifetime. Halley last appeared in the inner parts of the Solar System in 1986 and will next appear in mid-2061.

The comet is named after English astronomer Edmond Halley, who examined reports of a comet approaching Earth in 1531, 1607 and 1682. He concluded that these three comets were actually the same comet returning over and over again, and predicted the comet would come again in 1758.

Halley didn't live to see the comet's return, but his discovery led to the comet being named after him. (The traditional pronunciation of the name usually rhymes with valley.) Halley's calculations showed that at least some comets orbit the sun.

Further, the first Halley's Comet of the space age — in 1986 — saw several spacecraft approach its vicinity to sample its composition. High-powered telescopes also observed the comet as it swung by Earth.

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Dwarf planet Ceres is the largest object in the asteroid belt between Mars and Jupiter, and it's the only dwarf planet located in the inner solar system. It was the first member of the asteroid belt to be discovered when Giuseppe Piazzi spotted it in 1801.

Although it—and the next two asteroids discovered, Pallas and Juno—is located near the distance predicted by Bode’s law for the “missing” planet between Mars and Jupiter, most asteroids found subsequently are not so located, and so the agreement with that “law” appears to be coincidental.

Ceres’ shape and density are consistent with a two-layer model of a rocky core surrounded by a thick ice mantle. Ceres rotates once in 9.1 hours. Compositionally, the asteroid’s surface resembles the carbonaceous chondrite meteorites. Water vapour, the first detected in the asteroid belt, escapes into space when Ceres is closest to the Sun.

Ceres was designated a dwarf planet, a new category of solar system objects defined in August 2006 by the International Astronomical Union. (For a discussion of that decision, see planet.) The U.S. space probe Dawn studied the dwarf planet from March 2015 to November 2018. Dawn observed two very bright spots, Cerealia Facula and Vinalia Faculae, in Occator crater on Ceres.

Credit : Britannica

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Pluto has 5 moons. The largest, Charon, is so big that Pluto and Charon orbit each other like a double planet.

Pluto's highly elliptical orbit can take it more than 49 times as far out from the sun as Earth. Since the dwarf planet's orbit is so eccentric, or far from circular, Pluto's distance from the sun can vary considerably. The dwarf planet actually gets closer to the sun than Neptune is for 20 years out of Pluto's 248-Earth-years-long orbit, providing astronomers a rare chance to study this small, cold, distant world.

As a result of that orbit, after 20 years as the eighth planet (in order going out from the sun), in 1999, Pluto crossed Neptune's orbit to become the farthest planet from the sun (until it was demoted to the status of dwarf planet).

When Pluto is closer to the sun, its surface ices thaw and temporarily form a thin atmosphere, consisting mostly of nitrogen, with some methane. Pluto's low gravity, which is a little more than one-twentieth that of Earth's, causes this atmosphere to extend much higher in altitude than Earth's. When traveling farther away from the sun, most of Pluto's atmosphere is thought to freeze and all but disappear. Still, in the time that it does have an atmosphere, Pluto can apparently experience strong winds. The atmosphere also has brightness variations that could be explained by gravity waves, or air flowing over mountains.

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Neptune was the first planet to be discovered by using mathematics. After the discovery of Uranus in 1781, astronomers noticed that the planet was being pulled slightly out of its normal orbit. 

In retrospect, after it was discovered, it turned out it had been observed many times before but not recognized, and there were others who made various calculations about its location which did not lead to its observation. By 1847, the planet Uranus had completed nearly one full orbit since its discovery by William Herschel in 1781, and astronomers had detected a series of irregularities in its path that could not be entirely explained by Newton's law of universal gravitation. These irregularities could, however, be resolved if the gravity of a farther, unknown planet were disturbing its path around the Sun. In 1845, astronomers Urbain Le Verrier in Paris and John Couch Adams in Cambridge separately began calculations to determine the nature and position of such a planet. Le Verrier's success also led to a tense international dispute over priority, because shortly after the discovery George Airy, at the time British Astronomer Royal, announced that Adams had also predicted the discovery of the planet. Nevertheless, the Royal Society awarded Le Verrier the Copley medal in 1846 for his achievement, without mention of Adams. The Royal Society, however, also awarded Adams the Copley medal in 1848.

The discovery of Neptune led to the discovery of its moon, Triton, by William Lassell just seventeen days later.

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The moon Io is the most volcanically active world in the solar system. Io even has lakes of molten silicate lava on its surface.

However, Io is a very tiny moon that is enormously influenced by the gravity of the giant planet Jupiter. The gravitational attraction of Jupiter and its other moons exert such strong "pulls" on Io that it deforms continuously from strong internal tides. These tides produce a tremendous amount of internal friction. This friction heats the moon and enables the intense volcanic activity.

Io has hundreds of visible volcanic vents, some of which blast jets of frozen vapor and "volcanic snow" hundreds of miles high into its atmosphere. These gases could be the sole product of these eruptions, or there could be some associated silicate rock or molten sulfur present. The areas around these vents show evidence that they have been "resurfaced" with a flat layer of new material. These resurfaced areas are the dominant surface feature of Io. The very small number of impact craters on these surfaces, compared to other bodies in the solar system, is evidence of Io's continuous volcanic activity and resurfacing.

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Jupiter is the largest planet in the solar system. Jupiter is so big that all the other planets in the solar system could fit inside it. More than 1,300 Earths would fit inside Jupiter.

Naturally, Jupiter has the strongest magnetic field of all the planets, with a field that is 20,000 times that of Earth’s magnetic field. The gravity is much different too. Having more gravitational pull, someone standing on Jupiter would measure 2.4 times their Earth weight on Jupiter. That means if you weigh 120 pounds on Earth, then you would weigh 288 pounds on Jupiter.

Earth is much smaller than Jupiter. Earth is about 3,959 miles, while Jupiter measures in at 43,441 miles. Earth is 5.972 × 10^24 kg, while Jupiter is 1.898 × 10^27 kg. While Earth only has one moon, Jupiter has 16 confirmed moons. Jupiter also has four rings.

With such a size different, it only makes sense that 1,300 Earths could fit inside of Jupiter. It would take 3.5 Earths alone just to fit across Jupiter’s red spot. Jupiter is massive compared to our tiny planet, so it would naturally take this many Earths to fill Jupiter.

Credit : The Nine Planets

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A year on Mercury takes 87.97 Earth days; it takes 87.97 Earth days for Mercury to orbit the sun once.

Mercury's highly eccentric, egg-shaped orbit takes the planet as close as 29 million miles (47 million kilometers) and as far as 43 million miles (70 million kilometers) from the Sun. It speeds around the Sun every 88 days, traveling through space at nearly 29 miles (47 kilometers) per second, faster than any other planet.

Mercury spins slowly on its axis and completes one rotation every 59 Earth days. But when Mercury is moving fastest in its elliptical orbit around the Sun (and it is closest to the Sun), each rotation is not accompanied by sunrise and sunset like it is on most other planets. The morning Sun appears to rise briefly, set, and rise again from some parts of the planet's surface. The same thing happens in reverse at sunset for other parts of the surface. One Mercury solar day (one full day-night cycle) equals 176 Earth days – just over two years on Mercury.

Mercury's axis of rotation is tilted just 2 degrees with respect to the plane of its orbit around the Sun. That means it spins nearly perfectly upright and so does not experience seasons as many other planets do.

Credit : NASA Science

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The Kepler space telescope was a space telescope launched by NASA to discover Earth-size planets orbiting other stars. Named after astronomer Johannes Kepler, the spacecraft was launched on March 7, 2009, into an Earth-trailing heliocentric orbit. 

In 2013, Kepler was assigned a new mission called "K2." Two of the spacecraft's reaction wheels had failed, so engineers came up with a clever scheme to redesign the mission. K2 still hunted for planets, but it scanned a larger swath of sky than before, along the ecliptic plane. The mission began new types of research as well, such as the study of objects within our solar system, exploded stars, and distant supermassive black holes at the hearts of galaxies.

After nine years in deep space collecting data that indicate our sky to be filled with billions of hidden planets - more planets even than stars - NASA's Kepler space telescope has run out of fuel needed for further science operations. NASA has decided to retire the spacecraft within its current, safe orbit, away from Earth. Kepler leaves a legacy of more than 2,600 planet discoveries from outside our solar system, many of which could be promising places for life.

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Gamma Cephei Ab is an exoplanet approximately 45 light-years away in the constellation of Cepheus (the King). The planet was confirmed to be in orbit around Gamma Cephei A in 2002, but was first suspected to exist around 1988 (making this planet arguably the first true exoplanet discovered).

On September 24, 2002, Gamma Cephei Ab was finally confirmed. The team of astronomers (including William D. Cochran, Artie P. Hatzes, et al.) at the Planetary Systems and their Formation Workshop announced the preliminary confirmation of a long-suspected planet Gamma Cephei Ab with a minimum mass of 1.59 MJ (1.59 times that of Jupiter). The parameters were later recalculated when direct detection of the secondary star Gamma Cephei B allowed astronomers to better constrain the properties of the system. Gamma Cephei Ab moves in an elliptical orbit with a semimajor axis of 2.044 AU which takes almost two and a half years to complete. The eccentricity is 0.115, which means it moves between 1.81 and 2.28 AUs in orbital distance around Gamma Cephei A, which would place it from slightly beyond the orbit of Mars, to the inner Asteroid belt in the solar system.

Hipparcos data taken in 2006 constrains its mass below "13.3 MJ at the 95% confidence level, and 16.9 MJ at the 99.73% (3 ?) confidence level". This is not much to go on, but it is enough to verify that it is not another unseen brown or red dwarf.

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An exoplanet is any planet beyond our solar system. Most orbit other stars, but free-floating exoplanets, called rogue planets, orbit the galactic center and are untethered to any star.

Planets are much fainter than the stars they orbit. Hence, exoplanets are extremely difficult to detect. By far, the most successful technique for finding and studying exoplanets has been the radial velocity method, which measures the motion of host stars in response to gravitational tugs by their planets. Swiss astronomers Michel Mayor and Didier Queloz discovered the first planet using this technique, 51 Pegasi b, in the 1990s. Other techniques that have detected exoplanets are - pulsation timing, microlensing, and direct imaging.

The nearest exoplanets are located 4.2 light-years from Earth and orbit Proxima Centauri, the closest star to the Sun.

 In 2011 the Kepler said that they had discovered a planet, Kepler-22b, that was the first to be found in the habitable zone of a star like the Sun. They also discovered the first Earth-sized exoplanets, Kepler-20e and Kepler-20f. By the end of its mission in 2018, Kepler had discovered 2,741 planets, about two-thirds of all known exoplanets.

Credit : Business Standard

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