Humans will be
knowing more and reading more about “ Io, Europa,
Ganymede, and Callisto” – they are the “Galilean
moons” - the four largest moons of Jupiter . They were discovered by
Galileo Galilei around January 1610 and were the first group of objects found
to orbit another planet. Galileo's discovery showed the importance of the
telescope as a tool for astronomers by proving that there were objects in space
that cannot be seen by the naked eye. The fifth planet from the sun and the
heftiest in the solar system, Jupiter is known as a gas giant — a ball of
mainly hydrogen and helium — unlike rocky Earth and Mars. It is 11 times wider
than Earth and 300 times more massive than our planet. Researchers think it was
the first planet to form and that it holds clues to how the solar system
evolved.
Today
is significant day in the history of astronomy for NASA has confirmed having received
a signal from 540 million miles across the solar system, confirming its Juno
spacecraft has successfully started orbiting Jupiter, the largest planet in our
solar system. "Welcome to Jupiter!" flashed on screens at mission
control at NASA's Jet Propulsion Lab in Pasadena, California. The Juno team cheered and hugged.
Juno is a NASA New
Frontiers mission currently orbiting the planet Jupiter. Juno was launched from
Cape Canaveral Air Force Station on August 5, 2011 and reached destination
today ~5th July 2016. The
spacecraft is in a polar orbit to study Jupiter's composition, gravity field,
magnetic field, and polar magnetosphere. Juno will also search for clues about
how the planet formed, including whether it has a rocky core, the amount of
water present within the deep atmosphere, mass distribution, and its deep
winds, which can reach speeds of 618 kilometers per hour (384 mph). Still June is not the first, which credit
goes to Galileo probe which orbited from 1995–2003.
The Juno spacecraft
is powered by solar arrays, commonly used by satellites orbiting Earth and
working in the inner Solar System, whereas radioisotope thermoelectric
generators are commonly used for missions to the outer Solar System and beyond.
The spacecraft's name comes from Greco-Roman mythology. The god Jupiter drew a
veil of clouds around himself to hide his mischief, but his wife, the goddess
Juno, was able to peer through the clouds and see Jupiter's true nature. The
mission had previously been referred to by the backronym JUpiter Near-polar
Orbiter in a list of NASA acronyms.
Today
marks the culmination of a journey that commenced almost 5 years ago – its predecessor
Galileo was deliberately crashed into Jupiter on September 21, 2003, to protect
one of its discoveries -- a possible ocean beneath Jupiter's
moon Europa. Juno will help answer lot of questions by looking at Jupiter's
interior. The spacecraft will orbit the poles and try to dodge the planet's
most hazardous radiation belts. To protect the spacecraft from the radiation,
Juno has a shielded electronics vault.
Juno
is a spinning, robotic probe as wide as a basketball court. It will circle
Jupiter 37 times for 20 months, diving down to about 2,600 miles (4,100
kilometers) above the planet's dense clouds. The seven science
instruments on board will study Jupiter's auroras and help scientists better
understand the planet's origins, structure, atmosphere and magnetosphere. An
onboard color camera called JunoCam will take "spectacular close-up, color
images" of Jupiter, according to NASA. The space agency is asking the
public to help decide where to point the camera.
Interestingly,
three 1.5-inch Lego figurines are also on board Juno. One is a likeness of
Galileo Galilei -- the scientist who discovered Jupiter's four largest moons.
The other two represent the Roman god Jupiter and his wife Juno. They were
included to inspire children to study science and math. Nasa is using the
aluminium Lego figures to inspire children to explore science, technology and
engineering.
Nasa's Juno
spacecraft fired its main rocket engine to slow itself down from a speed of
165,000 mph (265,000 kph) and slip into orbit around Jupiter. In Greek and
Roman mythology, Jupiter drew a veil of clouds around himself to hide his
mischief. From Mount Olympus, Juno was able to peer through the clouds and
reveal Jupiter's true nature. Juno holds a magnifying glass to signify her
search for the truth, while her husband holds a lightning bolt. The third Lego
crew member is Galileo Galilei, who made several important discoveries about
Jupiter. Even as NASA attempts to inspire the next
generation of spacecraft engineers by encouraging children to explore subjects
such as science and technology – the legos are on a suicide mission. Juno, along with its
three passengers, meets its demise in 2018 when it deliberately dives into
Jupiter's atmosphere and disintegrates — a necessary sacrifice to prevent any
chance of accidentally crashing into the planet's potentially habitable moons.
If
successful, scientists will for the first time be able to see what lies beneath
Jupiter's atmosphere, and help unlock secrets about how the solar system
formed.
With regards – S.
Sampathkumar
5th July 2016.
