Humankind is getting very good at looking deep into space: We have already seen two neutron stars colliding, we have encountered mysterious radio blasts and we are about to see, for the first time, the event horizon of a black hole.
But there are still some surprises out there, right here in
our own corner of the Universe.
Upon retaking the observations of a nearby globular cluster,
the Hubble Space Telescope accidentally captured an unpublished galaxy. The
newly discovered galaxy was named Bedin I - and is almost as old as the
Universe.
The mission was to search for the weaker stars in NGC 6752,
a globular cluster 13,000 light-years away within the halo of the Milky Way.
But in the distance - about 30 million light-years away "ahead",
about 2,300 times farther away than the star they were staring at - Bedin I was
lurking.
Considering that our Local Group is about 10 million light
years in diameter. If you think of it as a neighborhood, the distance of 30
million is like being in the same cosmic city.
Bedin I is tiny, isolated and old. It is only 3,000
light-years across, compared to the 100,000 light-years in the Milky Way, and
is about 1,000 times weaker. It was classified as a dwarf spheroidal galaxy.
Generally, spheroidal dwarf galaxies are companions of galaxies or larger
systems, but not Bedin I. It is 2 million light-years from the nearest galaxy
to be considered a "satellite galaxy."
Based on the light it emits, scientists were able to
determine that the galaxy is very low in metals. And since the heavier
elements, such as metals, were created in stars and propagated by the Universe
after their death, this indicates that Bedin I has a very old population of
stars.
It has been estimated that the galaxy is 13 billion years
old, newer than the universe in about 800 million years. The low metal content
implies that Bedin I has not had any new star formation since. This means that
it is a kind of cosmic "living fossil" or time capsule, preserving
the conditions of the primordial Universe.
Reference(s): ScienceAlert