The Astronomical Society of the red Sea of Arabia, ASRA is pleased to publish, for the first time, some parts from an article written in the respectful Astronomy Magazine, the world's best seller astronomy magazine.
The title of the article is : 100 years of astronomical discoveries.
The complete article was published in the September 2016 issue of the magazine.
CONTINUATION OF THE ARTICLE.
THE FIRST DECADE OF THE NEW MILLENNIA THE 2000s.
2000
- A team of solar system hunters led by Canadian astronomer Brett Gladman find 11 previously unknown moons of Saturn.
- A team led by American astronomers Scott Sheppard and David Jewitt discovers 10 moons of Jupiter.
2001
- April sees the launch of the 2001 Mars Odyssey spacecraft, which enters Martian orbit six months later and begins science operations.
- Another team including astronomers Sheppard and Jewitt discovers another 11 moons of Jupiter.
- (Near Shoemaker Touches Down on 433 Eros)
Launched in 1996, the Near-Earth Asteroid Rendezvous-Shoemaker spacecraft set off on an ambitious mission to orbit and study the near Earth asteroid 433 Eros. The spacecraft carried an array of instruments, including an X-ray/gamma-ray spectrometer, a multi spectral camera, a laser rangefinder, a near-infrared imaging spectrograph, and a magnetometer. NEAR Shoemaker, named for planetary scientist Eugene Shoemaker, set goals of examining the composition, mineralogy, mass, and magnetic field of a near Earth asteroid for the first time.
En route to Eros, the spacecraft made a flyby of asteroid 253 Mathilde, studying it from a distance of 750 miles (1200 kilometers). On Valentine’s Day in 2000, after a journey of four years and one missed orbital insertion and subsequent recovery, the spacecraft closed in on Eros and began a year of orbital science.
On February 12, 2001, NEAR sets down on Eros surface. It’s wealths of data leads to the first three dimensional map of an asteroid, and the realization that Eros has been geologically active, with grooves, ridges, craters, and rocky debris. The team counts more than 100,000 craters larger than 50 feet on the asteroid which spans 21 miles (34 kilometers).
- (WMAP Examines Cosmic Microwave Background)
The Wilkinson Microwave Anisotropy Prob (WMAP), named for cosmologist David Wilkinson, launches in 2001 to study the cosmic microwave background radiation. Like its predecessor, the Cosmic Background Explorer, WMAP confirms and further refines cosmological data that supports our view of the Big Bang origin of the universe. Further, WMAP plays a significant role in confirming the current cosmological so-called Standard Model, known as Lambda-CDM (for Cold Dark Matter).
After more than 9 years of data collection, the satellite produces the following data set : The age of the universe is 13.77 billion years; the expansion rate of the universe is currently 69.3 km/s/megaparsec; and the composition of the universe is 71.4 percent dark energy, 24.0 percent dark matter, and 4.6 percent baryonic (normal) matter. These results will be further refined a decade later by the Planck satellite, but WMAP pushed our knowledge of the fundamental parameters of the universe a huge step forward.
2003
- American astronomer Scott Sheppard discovers nine more moons of Jupiter.
- American astronomers Mike Brown, Chad Trujillo, and David Rabinowitz discover icy dwarf planet Sedna far out in the solar system.
- Comet NEAT (C/2002 V1) grows bright, briefly, early in the year.
- Canadian astronomer Brett Gladman, and American astronomer Sheppard, and others find 12 new moons of Jupiter.
- Astronomers from several research groups discover three new moons of Uranus.
- (Hubble’s Magnificent Ultra Deep Field)
Aside from studying thousands of individual objects in the universe, the Hubble Space Telescope periodically focuses intensely on small region of the sky. In 1995, Hubble Space Telescope’s astronomers produced a “Hubble Deep Field” in the constellation Ursa Major, recording extremely distant galaxies to survey the early cosmos.
In 2003, Hubble’s astronomers take this approach a big step further with the Hubble Ultra Deep Field. The Hubble Ultra Deep Field focuses on a small region of space in the constellation Fornax and produces an image containing 10,000 distant galaxies in a field of view some 2.4 arc minutes on each side.
When it was completed in 2004, the Hubble Ultra Deep Field was the deepest image of the universe ever taken, and it is used as a search field for the most distant galaxies known. Some of these galaxies formed just 400 million to 800 million years after the Big Bang, and they are blobby protogalaxies, believed to have accreted by combination into more mature galaxies as the universe aged. Hubble astronomers find that during the formation of young galaxies, less than a billion years after the Big Bang, very high rates of of star formation occurred. They also catalog young galaxies - their sizes, characteristics, and luminosities - over a range of the early universe. They find that galaxy structures were primitive in the early universe, and that they evolved rapidly over time.
2004
- The Genesis spacecraft returns a sample of solar wind particles to Earth, a first time occurrence.
- The European Rosetta spacecraft launches toward Comet 67P/Churyumov - Gerasimenko. It will reach the comet after a 10 years journey.
- Voyager 1 spacecraft sends back data from within the heliosheath, the outer part of the Sun’s bubble - like region of space.
- (Spirit And Opportunity Rovers Explore Mars)
Launched in 2003, the Mars Exploration Rovers, Spirit and Opportunity, arrive on the Red Planet in January 2004 and commence explorations. The twin rovers measure som 5 by 7 by 5 feet (1.5 by 2 by 1.5 meters) and produce the largest trove of martian data up to their time.
Spirit lands in Gusev Crater, a site that seems to have been inundated by liquid water in Mars’ ancient history. Spirit goes on to explore Bonneville Crater, The Colombia Hills, Husband Hill, McCool Hill, Silica Valley, and other sites. Its twin, Opportunity, lands in Eagle Crater, and sets off to explore a series of important sites, including Endurance Crater, Erebus Crater, Victoria Crater, and Endeavor Crater.
Each rover carries a battery of numerous instruments and studies a wide range of martian science. Both rovers find a mesmerizing number of surprises : ancient acidic lake-beds; minerals like jarosite that require abundant liquid water to form; environments that would have been habitable for timescales of millions of years in the past; meteorites on the planet’s surface; wind blown dust and dust devils; systems of ancient hydrothermal flows; recent water and frosts; and a dynamic atmosphere.
- (Cassini - Huygens Spacecraft Orbits Saturn)
An enormous, large scale mission, the Cassini - Huygens spacecraft arrives at Saturn after a seven years cruise on July 1. The NASA spacecraft consists of two major elements : the Cassini Orbiter and the Huygens Prob, the later destined to land on Saturn’s moon Titan in 2005.
The Cassini mission is a spectacular success, with flybys of Earth, Venus, and Jupiter en route. The prob tested general relativity by using radio waves, and on its approach to Saturn it commenced major scientific operations using a large array of instruments.
Among the fruits of the mission is the discovery of six new moons of Saturn. In the summer Of 2004, the spacecraft flies past Saturn’s moon Phoebe, a heavily cratered satellite that probably holds large amounts of water ice. The spacecraft also conducts a flyby of Titan, revealing the moon’s surface for the first time. Radar images eventually uncover lakes of methane on the moon’s surface. The spacecraft also studies Saturn’s rings in unprecedented detail, observes storms on the planet, performs flybys of other moons, and returns spectacular amounts of data.
2005
- (Huygens Prob Lands On Surface Of Saturn’s Moon Titan)
Continuing the marvelous success of the Cassini mission to Saturn, 2005 sees the landing of the Huygens Prob on the surface of Saturn’s largest moon, Titan. This historic event marks the first landing of a spacecraft on an outer solar system body.
Separating from the Cassini orbiter in mid December 2004, Huygens maneuvers and lands on Titan on January 14. The lander carries an atmospheric structure instrument, a Doppler wind experiment, a decent imager, a mass spectrometer, and other hardware to investigate the large moon. The prob is designed to transmit data as it passes down through Titan’s atmosphere, and probably for a few minutes directly from the surface. Actually, it sends back data for 90 minutes while sitting on Titan.
Huygens returns incredible images from the surface that depict globules most likely composed of water ice, a substrate of finer-grained particles, and hazy, dense atmosphere close to the surface. One of the principal scientist described the moon’s surface as a hard clutter of objects sitting atop a sticky, dense muddy subsurface. A thin haze of methane covers everything. Images suggest “seas” of ethane and methane, along with drainage channels. The overall lighting is about one-one thousandth that of sunlight on Earth.
- (Deep Impact Spacecraft Strikes Comet 9P/Tempel 1)
On January12, NASA launch controllers sent the Deep Impact spacecraft on its journey toward Comet Tempel 1 (9P/Tempel 1), a periodic comet known since 1867. Some six months later, on July 4, the spacecraft images the approaching comet and then deploys an impactor to smash into the nucleus of Tempel 1, ejecting material in a cloud for the flyby spacecraft to study. The only previous missions sent to study comets were also flybys, beginning with Comet Halley in 1986. This mission ambitiously samples a comet and, by crashing into the nucleus, is able to determine what the comet is made of.
Beginning about 60 days before the encounter, Deep Impact took high precision measurements and images of the comet. During June, the spacecraft recorded two unusual outbursts of activity, and by month’s end it prepared for the impact phase.
Deep Impact maneuvers to place itself within the path of the oncoming comet and deploys the impactor, allowing Tempel 1 to slam into it. The spacecraft records a bright flash and cloud of debris a short time later. NASA finds the density of the comet to be like talcum powder, and observers evidence of clays, carbonates, sodium, and crystalline silicate minerals in the nucleus.
- A team of astronomers led by American astronomer Mike Brown announce the discovery of the dwarf planet Haumea.
- The Mars Reconnaissance Orbiter spacecraft launches, reaching the Red Planet seven months later.
- The European Space Agency’s Venus Express spacecraft launches, reaching the planet five months later.
- The Spirit rover on Mars performs the first astronomical observation from the surface of another planet ever, including imaging an eclipse when the moon Phobos moves into the shadow of Mars.
- A Hubble Space Telescope imaging team including American astronomer Hal Weaver and American engineer and planetary scientist Alan Stern discovers Nix and Hydra, two small moons of Pluto.
- The Japanese Hayabusa spacecraft explores asteroid 25143 Itokawa, imaging and collecting detailed data.
- (Astronomers Discovers Dwarf Planet Eris And Makemake)
In this year, a team of Caltech astronomers led by American astronomer Mike Brown makes some big discoveries in the distant solar system. In January, Brown’s team, which includes American astronomers Chad Trujillo and David Rabinowitz, detects a distant asteroid that would come to be classified as a dwarf planet. They name the object Eris, after the Greek goddess, a personification of strife and discord.
Soon astronomers confirm the existence of Eris and measure it to be 1445 miles (2326 kilometers) across, which turns out to be slightly smaller than Pluto (although at first it was believed to be somewhat larger than Pluto). Eris follows an orbit taking it far out to 97 times more distant than Earth is from the Sun, over a period of 558 years. Eris also has a very small moon, named Dysnomia.
Two months later, the same team finds a second distant object, which they named Makemake, after the mythology of Easter Island. Makemake is also found to be a dwarf planet, some 900 miles (1460 kilometers) across. It travels in an orbit that carries it 53 times farther away from the Sun than Earth, over a period of 309 years. In one year, the solar system gains two significant outer bodies.
2006
- In controversial action, the International Astronomical Union votes to demote Pluto to a dwarf planet from the full planetary status it enjoyed for 76 years.
- NASA’S New Horizons spacecraft launches for Pluto, arriving nine years later.
- The Japanese Hinode and U.S. STEREO spacecrafts launch to study the Sun.
- A team of astronomers led by American astronomers Sheppard and Jewitt discover six more moons of Saturn.
- (Stardust Mission Returns Cometary Dust to Earth)
A historic first takes place in January, when the Stardust robotic space probe lands in the Utah desert, carrying the first samples of cometary particles ever returned to Earth.
The mission commenced with a launch in 1999, after which the spacecraft flew past and studied the asteroid 5535 Annefrank, and then encountered and sampled the well known periodic Comet Wild 2 (81P/Wild). This comet is is 3.5 mile - diameter (5.5 kilometers) object that orbits the Sun between 1.5 and 5.3 times the distance between Earth and the Sun. Unusually, it passed within 600,000 miles (1 million kilometers) of Jupiter in 1974. The giant planet gravity altered Wild 2’s orbit to plunge it into the inner solar system.
Stardust carried several instruments, including a navigational camera, a cometary and interstellar dust analyzer, a dust flux monitor instrument, and most importantly, an aerogel dust particle collector. About the size of a tennis racket, the collector picked up particles as the spacecraft swooped through Comet Wild 2’s tail in 2004.
Two years later, scientists begin studying the cometary particles and eventually find they contain the simplest amino acid, glycine, one of the fundamental building blocks of life.
2007
- Comet McNaught (C/2006 P1) becomes brilliant in the Southern Hemisphere sky and is briefly visible in the north.
- The Phoenix Mars lander launches in August and arrives at Mars nine months later.
- The Japanese SELENE spacecraft, “aka Kaguya”, launches in September to study the Moon.
- In October, the Chinese “Change 1” lunar orbiter launches.
2008
- The Indian spacecraft “Chandrayaan 1” launches in October and studies the Moon, finding widespread water ice.
2009
- The NASA’s Lunar Reconnaissance Orbiter spacecraft launches to study the Moon.
- Astronomers celebrate first light for the 10.4 meter Gran Telescopio Canarias, currently the largest optical telescope in the world.
- (Kepler Space Telescope Launches Hunt For Exoplanets)
Astronomers discovered the first planet orbiting a star other than the Sun in 1992, and the first planet orbiting a Sun-like star in 1995. But the business of discovering extrasolar planets, or exoplanets, gets into high gear with the Kepler Space Telescope’s launch in 2009.
Named for the 17th-century’s Renaissance German astronomer and mathematician, Johannes Kepler, the instrument launches into an Earth-trailing, heliocentric orbit that places it slightly farther from the Sun than Earth. Kepler carries a 1.4 meter primary mirror and , at the time, the largest camera ever launched into space, consisting of 42 conjoined CCDs.
After its launch, Kepler wasted no time in cranking out exoplanet discoveries. Although the spacecraft observes a relatively small area of the sky - 100 square degrees centered between Cygnus and Lyra, and its stars mostly dozens or a few hundred light years into the galaxy - it becomes a workhorse. The telescope detects exoplanets by observing transits, when a planet moves in between us and its host star, causing a slight dip in the star’s light. To date, the spacecraft has uncovered more than 2200 planets orbiting other stars, and an additional 4500 candidate planets. From these results astronomers estimate that as many as 40 billion rocky Earth-size exoplanets could exist within habitable zones of their stars in the Milky Way Galaxy.
2010
- The Japanese Hayabusa spacecraft returns the first ever sample of an asteroid, 25143 Itokawa, to Earth.
- The NASA’s Solar Dynamics Observatory is launched in February to study the Sun.
- The NASA’s EPOXI mission flies past Comet 103P/Hartley.
- In May, the Japanese “Akatsuki probe” launches toward Venus.
- The Chinese “Change 2” probe launches in October, bound for the Moon.
To be continued in the final part, part 10
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Space