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Regarded by many as the most
valuable astronomical tool

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the Hubble Space Telescope is
approaching its 19th anniversary on space.

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Hubble sees into the far
reaches of the Universe,

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but its powerful instruments have
also surveyed our planetary neighbours.

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In this episode we will see what Hubble has
revealed to us in our own solar backyard.

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This is the Hubblecast.

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News and images from the
NASA / ESA Hubble Space Telescope.

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Travelling through time and space
with our host, Dr. J

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EPISODE 27: What has Hubble
taught us about planets?
a. k. a. Dr. Joe Liske.

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Hello and welcome to another
episode of the Hubblecast.

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Even those who, for some strange
reason, aren't astronomy enthusiasts

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are likely to recognise some
of Hubble's most famous images.

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Like the "Pillars of
Creation" in the Eagle Nebula

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or the Hubble Deep
and Ultra-Deep Fields,

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which have shown us some of the
most distant galaxies ever observed.

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The Hubble Space Telescope has
really fundamentally changed

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our understanding of
the Universe at large.

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But, with its high resolution images of
planets and moons in our own Solar System,

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it has also taught us a lot about
our own cosmic neighbourhood.

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Hubble cannot observe our Sun
or the closest planet, Mercury

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because its instruments are
light-sensitive and would be damaged.

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However, the telescope has examined
every other planet in the Solar System,

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including dwarf planets Pluto,

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Ceres

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and Eris.

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But, of course, Hubble has not
just produced pretty pictures.

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It provides planetary scientists with
vital information about our neighbours

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that may help us better understand
our own home planet Earth.

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The innermost planet in our Solar
System that Hubble has studied is Venus.

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In a sense, Hubble has acted as some
kind of interplanetary weather satellite

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to study Venus' climate.

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Now, the observations has shown
that the atmosphere of Venus

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is continuing to recover from an
intense bout of sulphuric acid rain,

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which was probably triggered by
the suspected eruption of a volcano

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in the late 1970s.

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On Mars, the red planet, Hubble has
been useful in tracking dust storms,

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a common Martian phenomenon that
can envelop the entire planet.

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Since Mars is a hub
of spacecraft activity,

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including both orbiters and rovers,

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it is vital to monitor
weather patterns there.

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After the terrestrial
planets come the gas giants,

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beginning with Jupiter, the
largest planet in our Solar System.

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From spectacular light
shows at the poles

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to a comet's impact,
Hubble has captured it all.

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Have you ever seen Earth's magnificent
northern or southern lights?

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All of the planets are
subjected to solar wind,

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charged particles ejected
from the Sun's atmosphere.

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When this wind collides with particles
within the planet's magnetic field,

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they give off light, creating
the familiar polar phenomenon.

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Using Hubble, astronomers have been able
to capture the same spectacle on Jupiter.

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Hubble caught the evidence of comet
Shoemaker-Levy's collision with Jupiter

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in the early 1990s.

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Seeing the aftermath of
the impact in such detail

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offered the unique opportunity
to witness this cosmic event

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without the danger of
experiencing it on Earth.

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Continuing its neighbourhood watch,

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Hubble has also taken
some breathtaking images

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of that wonderous ringed planet, Saturn.

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Again, with its sharp eyes,
it's been able to observe

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weather patterns on Saturn
and see some of its moons.

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Saturn's ring system is the largest
one known in the Solar System.

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Astronomers have long debated
the origin of these rings.

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Hubble data have helped
astronomers study the gas giant

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when the rings were at
maximum tilt towards the Earth.

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Saturn experiences seasonal tilts
away from and towards the Sun,

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much the same way as Earth does.

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Of Saturn's 60 known moons, Titan
is probably the most intriguing.

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That's because is so similar to the Earth
during one of its early phases of evolution

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and because it's got an ice volcano.

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In 1995, scientists from
Arizona captured the first images

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of the surface of Saturn's
giant, haze-shrouded moon, Titan.

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Hubble's groundbreaking
observations helped state the stage

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for NASA/ESA's Cassini mission,

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which sent the Huygens probe
to the surface of Titan,

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giving us close-up
images of this icy world.

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Saturn isn't the only
planet with a ring system.

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In fact, all of the
giant planet have one.

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Hubble has produced
one of the first images

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that revealed the angle of
the tilt of Uranus' rings.

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Hubble scientists were, for the
first time with visible light,

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able to detect clouds and wind speeds
in the northern hemisphere of Uranus.

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And Hubble data from Neptune have shown

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the planet's powerful
equatorial jet stream,

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immense storms and dark spots
in it's northern hemisphere.

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In a way, our solar
neighbourhood changed in 2006,

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when one of our planetary
neighbours, Pluto,

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was downgraded from a
planet to a dwarf planet.

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When it's closest to Earth,

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Pluto is still a whopping
4.28 billion kilometres away!

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To give you an idea of how far that
is, NASA's New Horizon's spacecraft

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it's currently on its way to Pluto

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and it should arrive there
in just about... 9 years.

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Using its Advanced Camera for Surveys,

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Hubble gave us the clearest view yet

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of the distant dwarf planet
Pluto and its moon, Charon.

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In 2006, using the same camera,

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Hubble confirmed two additional
dwarf planets: Ceres and Eris.

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Well, it's good to know your neighbours!

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You never know, what happens
to them could happen to us, too.

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This is Dr. J
signing off for the Hubblecast.

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Once again, nature has surprised us
beyond our wildest imagination...

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Hubblecast is produced
by ESA / Hubble

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at the European
Southern Observatory in Germany.

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The Hubble mission is a project
of international cooperation

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between NASA and
the European Space Agency.