When the theory of
relativity was being mapped out, Einstein didn’t think that one of his
predictions, the prediction that the light of a distant star being warped and
magnified by the gravity of an object in its path, would ever be observed.
Astronomers have laid eyes
upon Einstein’s prediction and used it to their incredible advantage. They used
such an observation to figure out the mass of a white dwarf!
An idea inhabiting only
theoretical dreams was dragged out into scientific reality in an incredibly
fantastic manner. This idea was rejected by Einstein.
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| Image Credit: NASA, ESA, and A. Feild (STScI) |
With mathematical equations
dragged into our physical world today, a new path of understanding galactic
evolution and history is now here.
It’s time for a story. In
order to fully understand the significance of this finding, a portion of Einstein’s
legend and legacy demands narration.
A key concept of Einstein’s
theory of general relativity is gravitational lensing occurring when light
bends around the gravitational field of another mass. A star, for example.
Theoretically, light is deflected by twice the expected amount of the traditional,
classic Newtonian laws of gravity.
The first piece of evidence
in confirming Einstein’s theory of general relativity was brought forth in the
year of 1919. A total solar eclipse was due to occur- light from Hyades star
cluster behind the sun could be detected in the darkness which was exactly what
needed to deem Einstein’s hypothesis correct. As though it were meant to be,
the measurements taken fell perfectly in line with Einstein’s prediction.
Einstein then went on to
suggest that the light emitted by a distant star would appear to be brighter
when it’s curved around the gravitational field of an object in its path. The
prediction stated that the curved space surrounding the object mimics a
magnifying glass of astronomical sizes, sizes applicable to space. Then, from
earth, when a star in the foreground passes between the observer and a star
behind it, gravitational microlensing forms an Einstein ring. The ring appears
to be a perfectly shaped circle of light. An example is provided below:
Unfortunately, die to the
vast distances in space, the chances of such a fantastic, scientific spectacle
are incredibly slim and the odds not in the favor of the Earth. Einstein
himself said in a 1936 Science article that “there is no hope of observing this
phenomenon directly.” In the past 80 years physicists and researchers have been
able to observe partial rings several time but wistfully, no complete, perfectly
formed rings.
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| Image Credit: NASA, ESA, and A. Feild (STScI) |
Another big prize in the
world of great astronomy is the observation of an asymmetrical Einstein rings.
Asymmetrical Einstein rings occur whenever two objects are slightly out of
alignment which creates an illusion of a shift in the background stellar
position. Other unfortunate news... no such rings were observed yet.
However, with many and great
thanks to the Hubble Space Telescope, researchers of Space Telescope Science
Institute saw such an asymmetric phenomenon in action in a star that isn’t our
sun. Einstein didn’t think this was very likely and this is utterly
brilliant!
Terry Oswalt, astronomer at
Embry-Riddle Aeronautical University said: “The ring and its brightening were
too small to be measured, but its asymmetry caused the distant star to appear
off-centre from its true position.”
Such a feat took incredible
dedication and long hours of studious work. Kailash Chandra Sahu, lead author
and astronomer of US Space Telescope Institute, and his team searched through
over 5,000 stars to spot the asymmetric alignment.
Their tedious work paid off
in a way not predicted by anyone. In their search, dwarf star Stein 2051-B
caught their eye. It was noticed to be asymmetrically aligned with another
distant star in March 2014. Due to the shift of the apparent background of the
star, researchers were then able to use the numbers and measurements to
estimate the dwarf star’s mass. Their epic findings showed the mass of 2051-B
to be approximately 68% of our sun.
New findings then showed
that the perpetually enigmatic Stein 2051-B resembles the average white dwarf
star, paired with a high mass and carbon-oxygen core. Scientists then went on
to predict that at least 97% of stars in the galaxy are either white dwarfs or
well on their way towards the end.
Oswalt then went on to state
the white dwarfs are the fossils of all prior generations of stars which puts
them as the ultimate factor to figuring out the history and evolution of galactic
structures in our universe, including our very own Milky Way.
With massive sky surveys
such as the Large Synoptic Survey Telescope which is due to fly in 2019, the
likelihood of the capture of such rare events using astrometric lensing
increases greatly. This opens up a whole new pathway towards the understanding
and investigation of our universe. This is legendary and Einstein would be
incredibly proud. After all, it’s his work in action, guiding all current and
future scientists.
The results have been
published in Science.
Every day, the statement “we
stand on the shoulder of giants” proves to be true. This serves as incentive to
all of us to work harder because what is deemed nearly impossible always proves
to be possible.
