MessageToEagle.com -
The origin of Earth's water is hotly debated. New discoveries suggest that our planet's seas could once have been giant icebergs floating through space.
ESA's Herschel infrared space observatory has found water in a comet with almost exactly the same composition as Earth's oceans.
The reason why it remains unclear how our oceans were created is because our planet formed at such high temperatures that any original water must have evaporated.
Yet today, two-thirds of the surface is covered in water and this must have been delivered from space after Earth cooled down.
Comets seem a natural explanation: they are giant icebergs travelling through space with orbits that take them across the paths of the
planets, making collisions possible.
The impact of comet Shoemaker-Levy 9 on Jupiter in 1994 was one such event.
But in the early Solar System, when there were larger numbers of comets around, collisions would have been much more common.
However, until now, astronomers' observations have failed to back up the idea that comets provided Earth's water.
The key measurement they make is the level of deuterium – a heavier form of hydrogen – found in water.
All the deuterium and hydrogen in the Universe was made just after the Big Bang, about 13.7 billion years ago, fixing the overall
ratio between the two kinds of atoms.
Measurements from the Herschel Space Observatory show that comet Hartley 2, which comes from the distant Kuiper Belt,
contains water with the same chemical signature as water in Earth's oceans. The findings may help explain how Earth’s surface ended up covered in water.
CREDIT: NASA/JPL-Caltech/R. Hurt
However, the ratio seen in water can vary from location to location. The chemical reactions involved in making ice in space lead to a higher or
lower chance of a deuterium atom replacing one of the two hydrogen
atoms in a water molecule, depending on the particular environmental conditions.
This illustration shows the orbit of comet Hartley 2 in relation to those of the five innermost planets of the Solar System.
The comet made its latest close pass of Earth on 20 October, coming to 19.45 million km. On this occasion, Herschel observed the comet.
The inset on the right side shows the image obtained with Herschel’s PACS instrument. The two lines are the water data from HIFI instrument.
Credits: ESA/AOES Medialab; Herschel/HssO Consortium
Thus, by comparing the deuterium to hydrogen ratio found in the water in Earth's oceans with that in extraterrestrial objects,
astronomers can aim to identify the origin of our water.
The nucleus of Comet Halley as seen from the Giotto spacecraft by the Halley Multicolour Camera.
Credits: MPAe, Lindau
All comets previously studied have shown deuterium levels around twice that of Earth's oceans.
If comets of this kind had collided with Earth, they could not have contributed more than a few percent of Earth's water.
In fact, astronomers had begun to think that meteorites had to be responsible, even though their water content is much lower.
Now, however, Herschel has studied comet Hartley 2 using HIFI, the most sensitive instrument so far for detecting
water in space, and has shown that at least this one comet does have ocean-like water.
The Heterodyne Instrument
for the Far Infrared (HIFI)
is a high-resolution heterodyne
spectrometer. It works by mixing
the incoming signal with a stable
monochromatic signal, generated
by a local oscillator, and extracting
the frequency difference for further
processing in a spectrometer. HIFI
will have seven separate local
oscillators covering two bands from
480-1250 gigaHertz and 1410–1910 gigaHertz.
HIFI was developed by a consortium
led by SRON (Groningen, The Netherlands).
Credits: ESA (image by C. Carreau)
The key to why comet Hartley 2 is different may be because of where it was born: far beyond Pluto, in a frigid region of
the Solar System known as the Kuiper Belt.
The other comets previously studied by astronomers are all thought to have formed near to Jupiter and Saturn before being
thrown out by the gravity of those giant planets, only to return much later from great distances.
Thus the new observations suggest that perhaps Earth's oceans came from comets after all – but only a specific family of
them, born in the outer Solar System.
Out there in the deep cold, the deuterium to hydrogen ratio imprinted into water ice might have been quite different from
that which arose in the warmer inner Solar System.
Herschel is now looking at other comets to see whether this picture can be backed up.
"Thanks to this detection made possible by Herschel, an old, very interesting discussion will be revived and invigorated,"
says Göran Pilbratt, ESA Herschel Project Scientist.
"It will be exciting to see where this discovery will take us."
MessageToEagle.com based on material provided by ESA
Invisible Powerful Wave Shaking Up Jupiter's Jet Streams
New movies of Jupiter are the first to catch an invisible wave shaking up one of the giant planet's jet streams,
an interaction that also takes place in Earth's atmosphere and influences the weather.
"This is the first time anyone has actually seen direct wave motion in one of Jupiter's jet streams," says Simon-Miller, the paper's lead author.
Moon's Abnormal Magnetic Anomalies Linked To Asteroid Collision
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Abnormal Star Discovered In The 'Forbidden Zone'
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The object is definitely not as its "contemporaries" that appeared immediately after the Big Bang event.
Thermonuclear Burning In A Neutron Star Detected For The First Time!
It's a very important discovery!
For the first time, an international team of scientists have detected all phases of thermonuclear burning in a
neutron star, located close to the center of the galaxy in the globular cluster Terzan 5.
Astronomical Mystery - Tremendous Explosion And Appearance Of Odd Rings
Twenty five years ago, on 1987 February 23, the brightest supernova of modern times was observed in the Large Magellanic Cloud.
The collision occurred at speeds near 60 million kilometers per hour and shock-heats the ring material causing it to glow.
Over time, astronomers have watched and waited for the expanding debris from this tremendous stellar explosion to crash into previously expelled material...
Why Do We See The Man In The Moon?
There’s something poetic about gazing up at the night sky, seeing the familiar face of the “Man in the Moon” who faithfully accompanies us through life.
The synchronous rotation of the Moon - it takes the same amount of time to spin around its own axis as it does to revolve around Earth -
is what causes the Moon to "lock eyes" with Earth.
Watching Volcanoes On Alien Worlds
Volcanoes display the awesome power of nature like few other events.
Now that astronomers are finding rocky worlds orbiting distant stars, they're asking the next logical questions:
Do any of those worlds have volcanoes? And if so, could we detect them?
Doesn't Secret Dark Matter Exist?
The more scientists study dark matter they know lesser and are not particularly optimistic about their results.
After completing this study, we know less about dark matter than we did before," said Matt Walker, of the Harvard-Smithsonian Center for Astrophysics.
A mysterious and still unknown substance is totally invisible in the Universe and reveals its presence only through its gravitational pull...
Dwarf Irregular Galaxy That Forces Scientists To Re-Evaluate Old Theory
Astronomers from Center for Astrophysics of the University of Porto, Portugal and Oskar Klein Centre, Stockholm University, Sweden come up
with new findings regarding one of the most studied objects - the dwarf galaxy I Zw 18.
The results led the scientists to the conclusion that this enigmatic blue compact dwarf might force
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Violent Dragon Clash Billions Of Years Ago
NGC 5907 is sometimes called the "Splinter" or Knife Edge Galaxy because of its unusual appearance.
It is a spiral galaxy lying in the Dragon constellation,
about 40 million light-years from Earth that could have been formed through a gigantic collision of galaxies, 8 to 9 billion years ago.
MessageToEagle.com -
The origin of Earth's water is hotly debated. New discoveries suggest that our planet's seas could once have been giant icebergs floating through space.
New movies of Jupiter are the first to catch an invisible wave shaking up one of the giant planet's jet streams,
an interaction that also takes place in Earth's atmosphere and influences the weather.
"This is the first time anyone has actually seen direct wave motion in one of Jupiter's jet streams," says Simon-Miller, the paper's lead author.
A massive asteroid collision with the Moon left behind an enormous crater on the lunar surface and may have contributed to the strong magnetic
anomalies seen on the Moon.
The vast swaths of highly magnetic material were found in some parts of the moon's crust and this discovery contributed to a number of very
complex theories to explain the phenomenon...
Hiding behind clouds of dust, quasars are among the most energetic objects in the universe, with some of them as luminous as ten thousand Milky Way galaxies.
Quasars are thought to have massive black holes at their cores, and astronomers also think that the regions around the black holes actively accrete matter...
Is the Alcubierre warp drive a doomsday weapon or our passport to the Universe?
The Alcubierre warp drive is a theoretical tool that would allow for spacecraft to travel long distances in space rapidly,
by deforming the space-time continuum in a bubble around the spaceship...
A team of astrophysicists from Germany, France and Italy have discovered in the constellation Leo is an old star.
The star's existence raised at once many questions for scientists.
The object is definitely not as its "contemporaries" that appeared immediately after the Big Bang event.
It's a very important discovery!
For the first time, an international team of scientists have detected all phases of thermonuclear burning in a
neutron star, located close to the center of the galaxy in the globular cluster Terzan 5.
Twenty five years ago, on 1987 February 23, the brightest supernova of modern times was observed in the Large Magellanic Cloud.
There’s something poetic about gazing up at the night sky, seeing the familiar face of the “Man in the Moon” who faithfully accompanies us through life.
The synchronous rotation of the Moon - it takes the same amount of time to spin around its own axis as it does to revolve around Earth -
is what causes the Moon to "lock eyes" with Earth.
Volcanoes display the awesome power of nature like few other events.
Now that astronomers are finding rocky worlds orbiting distant stars, they're asking the next logical questions:
Do any of those worlds have volcanoes? And if so, could we detect them?
The more scientists study dark matter they know lesser and are not particularly optimistic about their results.
Astronomers from Center for Astrophysics of the University of Porto, Portugal and Oskar Klein Centre, Stockholm University, Sweden come up
with new findings regarding one of the most studied objects - the dwarf galaxy I Zw 18.
NGC 5907 is sometimes called the "Splinter" or Knife Edge Galaxy because of its unusual appearance.
It is a spiral galaxy lying in the Dragon constellation,
about 40 million light-years from Earth that could have been formed through a gigantic collision of galaxies, 8 to 9 billion years ago.