by David Reneke
Dave Reneke brings
news from the space and astronomy communities around the
David Reneke is an
astronomy lecturer and teacher, a feature writer for
major Australian newspapers and magazines, and a science
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Storms to Impact Earth
Beware the solar maximum - that’s the dire warning from senior space
They believe the Earth will be hit with
unprecedented levels of magnetic energy from solar flares after the
Sun wakes from a deep slumber sometime around 2013. National power
grids could overheat and air travel could be severely disrupted
while electronic items, navigation devices and major satellites
could stop working.
Severe solar flares, the strongest in 100 years, could result in
widespread power blackouts and leave cities without critical
communication signals for long periods of time, warns Dr Richard
Fisher, director of NASA’s Heliophysics Division.
The solar storms that will cause the Sun to reach temperatures of
more than 10,000°F occur only a few times over a person’s life.
Every 22 years the Sun’s magnetic energy cycle peaks while the
number of sun spots and solar flares hits a maximum level every 11
years. This is the
solar maximum you hear so much
And of course there is a
solar minimum - that’s what
we’re in now.
NASA said the super storm would hit like “a bolt of lightning”,
causing catastrophic consequences for the world’s health, emergency
services and national security unless precautions are taken.
Communication devices such as satellites and SatNavs through to air
travel and our banking system will be at risk.
Anything we rely on that is sensitive to
magnetic fields, like computers and iPods, could be affected.
“We know it is coming but we don’t
know how bad it is going to be,” Fisher said. “Systems will just
not work. The flares change the magnetic field on the Earth and
it’s rapid, just like a lightning bolt. That’s the solar
A space weather conference in Washington
DC attended by NASA scientists, policy-makers, researchers and
government officials was told of similar warnings. One thing is
certain, large areas will be without power and essential services,
and to repair that damage will be hard as it takes time.
The Sun has plenty of that, another five
billion years worth in fact!
Misfit or Par for the Course?
Astronomers are technically trained, pragmatic people, constantly
prepared to expect the unexpected. It’s a logic honed from many
years peering through telescopes at strange things in the night sky.
They’ve seen and photographed some of
the most indelible sights in the heavens - colliding galaxies,
magnetars, hypervelocity stars and many more examples of nature’s
Now they say they’ve spotted a planet
with a tail.
But hang on, planets don’t have tails! Well, they didn’t, until the
21st century rolled around. We’ve got new technology now,
much better telescopes, and have come to expect the unforeseen. But
this discovery was like nothing anybody had ever dreamed of ever
seeing - a planet with a distinct and definitive tail.
Astronomers using NASA’s Hubble Space Telescope have
confirmed the existence of a baked object that could be called a
The giant gas planet, named
HD 209458b, is orbiting so close to
its star that its heated atmosphere is escaping into space.
While it’s been speculated that stars
can blast away planets’ masses, this is the first confirmation that
atmospheric stripping is a real phenomenon. And since HD 209458b is
a pretty typical “hot Jupiter” - the nickname for close orbiting gas
giants - it’s almost certain that all hot Jupiters have
Observations taken with Hubble’s Cosmic Origins Spectrograph
suggest that powerful stellar winds are sweeping the cast off
atmospheric material behind the scorched planet, funneling it into a
previously assumed comet-like tail. The planet, located 153 light
years from Earth, weighs slightly less than Jupiter but orbits 100
times closer to its star than the Jovian giant.
This roasted, rocky world zips around
its star in a short 3.5 days; for comparison, our fastest planet,
Mercury, orbits the Sun in 88 days. This extrasolar planet is one of
the most intensely scrutinized because it is the first of the few
known alien worlds that can be seen passing in front of, or
transiting, its star.
Jeffrey Linsky, an astronomer at
the University of Colorado, and his team used COS to analyze the
planet’s atmosphere during transiting events to determine its
structure and chemical makeup by sampling the starlight that passes
The dip in starlight is usually very small, about 1.5%. But when the
planet’s atmosphere is added, the dip jumps to a whopping 8%,
indicating a bloated atmosphere. Early results show the presence of
the heavy elements carbon and silicon in the planet’s super-hot
2000°F atmosphere. This is assumed to be a by-product of the star’s
heat dredging up the heavier elements, allowing them to escape the
The COS data also showed gas escaping at high velocities, with a
large amount of it flowing forward at more than 35,000 km/h.
Now, like a thrilling dime store novel,
the mystery is starting to untangle. It’s likely that this large gas
flow is swept up by the stellar wind to form the comet-like tail
trailing the planet. It’s simply the most logical conclusion.
Hubble’s newest spectrograph has the ability to probe a planet’s
chemistry at ultraviolet wavelengths not accessible to ground-based
An earlier scan in 2003 showed an
active, evaporating atmosphere, and a comet-tail-like structure
was suggested as a possibility. But back then Hubble wasn’t able to
obtain the spectroscopic detail necessary to show a tail, or an
Earthward-moving component of the gas, during transits. The
instrumental sensitivity just wasn’t available back then.
Although this extreme planet is being roasted by its star, it won’t
be destroyed anytime soon.
“It will take about a trillion years
for the planet to evaporate,” Linsky said.
It’s unclear how long the superheated
alien world’s “tail” is or how long it’s been losing mass, but it’s
almost certain that the erosion process has been happening for at
least several million years.
Among the more than 400 planets found beyond our solar system there
are volcanic super-Earths, gas giants that dwarf Jupiter, and worlds
with multiple sunsets. Astronomers think that massive hot Jupiters
are born far away from their stars and approach them gradually
during eons of orbiting.
Many unanswered questions remain about the properties of
exoplanets, such as the details of their composition and their
likelihood of possessing moons. Another question is whether they
might support life. Several large planets do have orbits in their
parent star’s habitable zone, where it should be possible for
Earth-like conditions to prevail.
If these planets also have large moons,
the moons might be a more plausible location for life.
Wanderers from Another Star System?
Comets, long-lost members of the solar system’s fragmentary birth,
have always been a mystery.
In the Middle Ages they were seen as
portents of disaster, invoking dire warnings of fire, flood, disease
and pestilence. Some religious groups even believed they were the
dearly departed souls of their loved ones making their way to
These days we know them more as a fascination to look up at in the
night sky, to photograph and marvel at. But, where did they come
from? That’s a good question, and the answer may not be from where
Along with asteroids they make up the flotsam and jetsam of our
solar system. Astronomers believe that they originated great
distances away, traveling to the inner solar system from that frozen
region outside Pluto called
the Oort cloud, halfway to the
nearest star. They are the icy counterparts of asteroids impregnated
with life-giving water-ice, and perhaps the building blocks of life.
New computer simulations show that many comets - including some
famous ones - came from even farther out. They may have been born in
other solar systems.
Many of the most well-known comets,
Hale-Bopp, Halley, and most
McNaught, may have formed around
other stars before becoming gravitationally captured by our Sun when
it was still in its birth cluster.
Computer simulations by scientists like Dr Hal Levison from
the Southwest Research Institute in Boulder, Colorado, show
that the Sun may have captured small icy bodies from its sibling
stars while still in its star-forming nursery cluster.
The researchers investigated what fraction of comets might be able
to travel from the outer reaches of one star to the outer reaches of
another. The simulations imply that a substantial number of comets
can be captured through this mechanism, and that a large number of
Oort cloud comets come from other stars.
The results may explain why the number of comets in the Oort cloud
is larger than models predict.
“We can conclude that more than 90%
of the observed Oort cloud comets have an extra-solar origin,”