As Arthur C Clarke said, “Two possibilities exist, either we are alone in this universe or we are
not. Both are equally terrifying”. And terrifying it is. One of the biggest questions that almost
everyone of us would have wondered about is: Are we alone in this universe? Is anyone out there?
If yes, then why haven’t we found them yet? Would they be more intelligent than us?
What would their technology be like? How could we detect them? The list of questions is
endless and the possibilities too. One such possibility is a concept of Dyson sphere,
and today we are going to discuss about a recent study that tries to answer these questions.
A recent research has provided some solutions to these problems - at least if the device in
question is a Dyson sphere, a sort of mad energy harvester that draws energy from a black hole.
"The energy source of a well-developed Type II or Type III civilisation is considered in this paper.
They require a more powerful energy source than the Sun "In their article,
the researchers write. "Power stations for a Type II civilisation might include an accretion disc,
a corona, and relativistic jets.
Our findings show that an accretion disc might offer hundreds of times more brightness
than a main sequence star for a stellar-mass black hole, even at a low Eddington ratio."
However, considering that active black holes already release a significant amount of radiation
in each of these wavelength bands, detecting the Dyson excess may be easier said than done.
Other observations, such as variations in light when the black hole is minutely impacted by the
gravity of the sphere, the team says, might help disclose where these structures could be hidden.
Aliens with advanced technology may be powering their civilisation using
a hypothetical megastructure called a Dyson sphere that harvests energy from a black hole.
A recent study implies that the sphere may radiate in unusual ways, allowing
observatories on Earth to find the existence of sentient creatures elsewhere in the cosmos.
According to Live Science's sister site Space.com, a Dyson sphere is a hypothetical construction
that would ring a star with a tight configuration of orbiting platforms in order to absorb sunlight
and create electricity. The concept was first presented by theoretical physicist Freeman
Dyson in 1960, and it might be realised by a spacefaring alien society that had
spread out beyond its star system and hence required ever-increasing quantities of energy.
Freeman Dyson, a theoretical physicist, promoted the notion of a Dyson sphere in the 1960s
as a solution to the problem of power consumption that surpasses the capacities of a civilization's
planet. The sphere is created around the star of the planetary system — a megastructure
that gathers the star's energy at its source. Dyson's study hypothesised that while the Dyson
structure gathers and transforms stellar energy, infrared emissions of thermal energy may escape,
potentially revealing the presence of these hypothetical structures.
If we could detect this infrared signature, we would be able to zero in on alien civilizations. A
team of academics led by astronomer Tiger Yu-Yang Hsiao of Taiwan's National Tsing Hua University
has taken the notion a step further. What if the Dyson sphere (or Dyson ring)
was placed around a black hole? Would it work, and if so, what would we be able to detect from Earth?
A recent research suggests that instead of building a Dyson sphere around a star,
a civilisation can build a comparable megastructure around black holes.
A black hole is a region of space with such strong gravitational attraction that nothing,
not even light, can escape its gravitational pull.
Every large galaxy, according to astronomers, contains a black hole at its heart.
The one thing above all others that black holes are known for is their powerful gravitational
field that slurps up everything that draws close enough, and doesn't let it out again
(that we can detect). You might, therefore, be wondering how one could harvest anything from
such a beast. As it turns out, there are a number of processes in the extreme environment around a
black hole from which energy could possibly be harvested. In their paper, the team consider a
number of these processes: the accretion disk of material swirling around a black hole,
super-heated by friction to up to millions of degrees; Hawking radiation,
the theoretical black-body radiation emitted by black holes proposed by Stephen Hawking.
Other potentially relevant phenomena that could contribute include spherical accretion,
the corona of magnetized plasma between the inner edge of the accretion disk and the event horizon,
and the jets launched at relativistic speeds from the poles of active black holes.
Based on models of black holes clocking in at 5, 20, and 4 million times the mass of the Sun (which
is the mass of Sagittarius A*, the supermassive black hole at the heart of the Milky Way),
Hsiao and colleagues were able to determine that a sphere of satellites
would be able to effectively harvest energy from some of these processes.
An accretion disc may accumulate the most light, reaching 100,000 times the luminosity of the Sun,
enough to sustain a Type II civilisation. Furthermore, if a Dyson sphere gathers not
just electromagnetic radiation from the jets but also other forms of energy (e.g., kinetic energy),
the total gathered energy would be nearly five times greater. The researchers discovered that
such structures would be detected across many wavelengths, with hotter Dyson spheres visible
in ultraviolet and colder Dyson spheres visible in infrared, precisely as Dyson anticipated.
The researchers behind the new study suggest that building a Dyson sphere around a black hole
would allow an alien civilization to garner energy from six sources:
The cosmic microwave background, electromagnetic radiation left over from the Big Bang
Hawking radiation, theoretical radiation released by the black hole
The accretion disk, a disk of material that orbits around a black hole
Bondi accretion, the spherical accretion of ionized gas around an object.
A corona, a bright region of white light above a black hole that forms from hot gas particles.
Powerful jets of radiation and particles emitted from the black hole at nearly the speed of light.
By not only relying on radiation as the main source of energy but a Dyson sphere
around a black hole would also collect five times as much energy as one around a star,
according to the study. But constructing a sphere around a star sounds tricky enough — civilizations
would need materials that would not tear themselves apart or gravitationally attach
themselves around any nearby objects. There’s also a possibility that a meteor or asteroid
could nudge one of the pieces out of place. Consider a Dyson Sphere to be a big structure
atop a wall. The fundamental component is similar to a little brick, and we know how
to construct bricks to construct solar panels and load them into space. If we want to have so many
of them that they block a major portion of the sun's light, we'd have to create billions upon
billions more of them. And that is difficult. How difficult is it? You may require the
equivalent of an entire planet's worth of stuff. Combining such difficulties with the qualities
of a black hole makes things considerably more difficult. Black holes consume material from
nearby stars or other objects, and some of that material subsequently bursts out in the form of
two tremendous jets. The event horizon of a black hole is a border that defines the black hole from
which nothing that enters the black hole can be viewed from the outside. If a building were to be
erected near the event horizon of a black hole, it would be continually disturbed by falling debris
and would have to be engineered to withstand temperatures of up to 2,700 degrees Celsius.
On the other hand, pairs of particles, one particle and one antiparticle,
separate due to the strong gravitational field whereby one gets inside the event horizon,
and the other is emitted as radiation. Using that radiation and the radiation of
the accretion disc, there is a lot of potential energy swarming around a black hole. If a strong
enough material is used, an alien civilization could potentially tame a black hole, feeding it
matter to produce energy and harness its force. Should a civilization this advanced exist,
then they would probably already know of our existence by the time we discover the black
hole Dyson sphere. It would be impossible to build a Dyson sphere around any object that size
with current known materials. But the type of civilization that would be interested in taking
on such an engineering challenge would most likely have much stronger materials than we do today.
Alternatively, they could work with known materials to create a Dyson Swarm or Dyson Bubble,
which doesn’t require as much material strength but does lose some of the energy that a complete
sphere would capture, and adds multiple layers of complexity when coordinating orbital paths
and other factors. Any such structure would have to be outside the accretion disk to get the full
benefit from the energy the black hole emits. So what do you think about such structure? Will
it be possible to build a dyson sphere around a balckhole? Let us know what you think in
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