Transcript Mysteries of Space

Space and Unsolved
Mysteries
Black Holes
• Form from the death of a very large star (
more than 25 solar masses). A supernova
occurs followed by a black hole
• Strangest objects in the universe
• Their existence was predicted before they
were discovered
• When astronomers say they have found a
black hole, they have not seen it but have
detected the gravitational effects of one.
• When black holes are “devouring” matter they
emit intense radiation and reach high
temperatures that temporarily expose the
location of the black hole.
• A black hole is a region of space from
which nothing, not even light, can escape.
It is the result of the deformation of
spacetime caused by a very compact
mass.
Black Holes in our Galaxy?
• In 1998, astronomers found compelling
evidence that a supermassive black hole of
more than 2 million solar masses is located
near the Sagittarius region in the centre of the
Milky Way Galaxy. More recent results using
additional data indicate that the supermassive
black hole is more than 4 million solar
masses
• Matter enters a black hole by its gravity when
it reaches “the point of no return” it is supercompressed and then disappears.
Dark Matter
• The structure of Andromeda is similar to our
Milky Way.
• Astronomers have studied it at length
because of this and based on light emission
and comparison to our galaxy scientists have
concluded it is similar in mass to the Milky
Way
• Dark matter appears around the Andromeda
Galaxy
• Dark matter is the most abundant form of
matter in the universe: invisible to telescopes
Andromeda
• The mass discovered by scientists for this
galaxy used the estimated mass to estimate
the speed of various stars movement and
discovered that they are moving much faster
than predicted. The way scientists have
explained this phenomenon is that there must
be 90 times more matter that is not visible to
account for the speed: therefore dark matter
is much more abundant than visible matter.
The search for Dark Matter
• The search has been going on since the
90’s
• It is elusive because it only seems to
interact with visible matter through its
weak gravitational effects. Because of
these weak effects it does not conform
to the shape of a spiral galaxy and
forms a halo around the galaxy
Dark Matter
•
Dark Matter and the Milky
Since a halo of dark
Way
Galaxy
matter was found around
Andromeda, scientists
wondered if it could be
seen around Our Galaxy.
They believe that it is.
• Astronomers have
estimated the mass of
the Milky Way to be
about 200 billion solar
masses but the motion
of small nearby galaxies
around ours indicated a
mass 10 times larger.
This means that only
10% of the milky way is
made up of visible
matter.
Dark Energy
•
•
•
•
Visible matter makes up 4%
Dark matter makes up 23%
The rest is Dark Energy
What is it--it is a force that has allowed
the matter in the universe to break free
from gravity and causes the expansion
of the universe
• Scientists observed Supernovae explosions
of white dwarf stars and plotted their
magnitude against their red-shift and found
that they were much farther than the
scientists inferred.
• Astronomers predicted that after the Big Bang
the universe should be gradually slowing
down in expansion due to gravity, but the
supernovae data shows the universe
expansion is accelerating.