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The Hubble Space Telescope has
solved a long-standing puzzle

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by resolving giant but delicate filaments
shaped by a strong magnetic field

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around the active galaxy NGC 1275.

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It is the most striking example so far

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of the influence of the immense tentacles
of extra-galactic magnetic fields.

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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 18: Hubble sees magnetic
monster in erupting galaxy.
a.k.a. Dr. Joe Liske.

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Hi and welcome to another
episode of the Hubblecast.

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Today we are going to interrupt our
series of seven Hubblecast specials

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to bring you a breaking new story.

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Now this doesn't happen very often,
but the subject of today's show

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is in fact completely invisible.

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And no, I'm not talking about dark
matter, I'm talking about magnetic fields.

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Although most people are
completely unaware of them,

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magnetic fields in fact
surround us all the time.

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For starters, the Earth has a magnetic field
of course, which any compass will show you.

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But power lines, and pretty much any
electrical device also produces magnetic fields.

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And moreover, they're not
just down here on Earth,

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they're also sprinkled
throughout the Universe.

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Take our Sun for example.

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Particularly strong
magnetic flares from our Sun

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can even disrupt radio
communication down here on Earth,

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including your mobile phone calls
and your favourite radio station.

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In the direction of the constellation Perseus
we find the Perseus cluster of galaxies.

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NGC 1275, in its centre, is one of
the closest giant elliptical galaxies.

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Its most spectacular feature is the
lazy filigree of gaseous filaments

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reaching out beyond the galaxy
into the multi-million degree

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x- ray emitting gas that
pervades the cluster.

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This is an active galaxy, hosting a
super-massive black hole at its core,

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which blows bubbles of material
into the surrounding cluster gas.

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Exploiting Hubble's view,
a team of astronomers

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led by Andy Fabian from the University
of Cambridge in the United Kingdom,

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have for the first time resolved individual
threads of gas, which make up the filaments.

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So, the amount of gas in one of these threads
is about a million times the mass of the Sun.

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They are only about 200 light years
across, but they are very straight

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and they can extend for
up to 20,000 light years.

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These filaments are formed when
cold gas from the core of the galaxy

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is dragged out in the wake of the
raising bubbles blown by the black hole.

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But the really interesting
thing is that these filaments

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appear to be able to survive
for up to 100 million years.

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And that's what had
astronomers really puzzled.

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How is it possible that these delicate
filamentary structures can survive

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in the hostile high-energy environment
of the galaxy cluster for so long?

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Either they should have heated up, disperse
and evaporated in a very short period of time,

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or, if they are somehow shielded,
they should have collapsed

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under their own weight
and form stars long ago.

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The new study published in Nature on the
21st of August 2008 gives the explanation.

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Magnetic fields provide
a skeletal structure

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strong enough to resist
gravitational collapse

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Preventing the filaments
from forming into stars.

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These magnetic fields have
been able to contain and suspend

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the peculiarly long threads
for over 100 million years.

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Well, there you have it!

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But why is it so important that scientists
have resolved these fine filamentary structures?

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Well, first of all it's allowed
them to finally measure the strength

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of an extragalactic magnetic field.

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But in addition to that, these filaments are
clear evidence of the intricate relationship

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between the central super-massive black
hole and the surrounding cluster gas.

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Understanding this relationship
provides us with important clues

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on how the giant black hole interacts with
and affects their surrounding environment.

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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.