Stars burst to life before Hubble's lens
October 21, 1997
Web posted at: 1:11 p.m. EDT (1711 GMT)
BALTIMORE (CNN) -- NASA's Hubble Space Telescope has
uncovered more than 1,000 bright, young star clusters
bursting to life in a brief but intense "fireworks show" at
the heart of a pair of colliding galaxies, the Space
Telescope Science Institute in Maryland said Tuesday.
The photographs Hubble relayed back to Earth may tell
scientists how a collision between our own galaxy and the
Andromeda galaxy, expected in several billion years, could
alter the two systems.
The pictures also provide further support for a scientific
theory that if one disk-shaped, or spiral, galaxy collides
into another, the result is an elliptical galaxy with far
more stars than either of the original galaxies contained,
including many star clusters.
Galaxies realign, stars form
It was once commonly believed that these globular star
clusters were remnants from the start of a galaxy's creation.
Now, most scientists think that the ages of the clusters may
provide a clock for estimating the age of a collision -- not
the age of the original galaxy.
Scientists who support this theory believe that the
additional star clusters are formed when massive clouds of
hydrogen gas -- measuring tens to hundreds of light-years
across -- in the spiral galaxies are compressed and then
ignite, triggering the new stars' sudden formation.
The Hubble pictures came from nearby galactic-scale
collisions, including the Antennae galaxies, so called
because a pair of long, luminous tails resembling an insect's
antennae were formed when they began their ongoing collision.
Although the Antennae are relatively close to Earth in
astronomical terms, ground-based telescopes were only able to
see the brightest of the clusters created by the crash, and
even in those cases could not show that the clusters were
But Hubble's resolution and sensitivity allowed NASA
scientists to uncover more than 1,000 exceptionally bright
young star clusters there.
In fact, even before its February upgrade, Hubble was able to
see more than any ground-based telescopes, NASA said. That
mission improved Hubble's "vision" into the infrared range.
Overall, NASA officials estimate the Hubble, launched in
1990, has cost $3 billion.
Milky Way also headed for crash
If Hubble were around to witness it, the far-seeing telescope
might snap similar pictures of the Milky Way and the
Andromeda galaxy when they crash into each other.
The two galaxies are on a collision course, closing the gap
at a speed of 300,000 miles per hour. As Andromeda is
currently 2.2 million light years away, the collision will
happen no sooner than 5 billion years in the future, by which
point the sun may have burned out, reducing the Earth to a
lifeless lump of rock.
Even if there were someone here to observe the collision,
they would be unlikely to see it from beginning to end. NASA
scientists say the crash will probably take several billion
years to run its course.
During the collision, they predict, molecular hydrogen clouds
will compress and explode, triggering the formation of
thousands of new star clusters. The galaxies' gravitational
pulls will draw Andromeda and the Milky Way into one
elliptical galaxy, with thousands of old and new stars
The turmoil will be such that in the end, they say, an
observer would see no sign of the former, majestic spiral
galaxies that our ancient civilization knew as the Milky Way
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