Tag: astrophysics

Forget Radio Telescopes—Aliens Could Be Using Gravitational Waves to Communicate

One of the most exciting breakthroughs in astronomy over the past decade was the detection of gravitational waves. Since the days of Galileo Galilei, astronomy was about the detection of electromagnetic signals with telescopes. As it turns out, the main constituents of the Universe are not observable in that way.

Our current data indicates that 85% of the matter in the Universe is invisible electromagnetically, constituting dark matter. In addition, 70% of the energy budget of the Universe is dark energy. Cosmologists infer these constituents because they affect visible matter gravitationally. Can we build a detector of near-Earth objects that would sense the gravitational signal of passing dark objects?

If dark matter is made of asteroid-mass objects, like primordial black holes, our telescopes would not notice them even when they pass near Earth. In a recent paper, I showed that the LIGO-Virgo-KAGRA gravitational wave observatories could detect a dark object if it moves close to the speed of light and its mass is larger than a hundred million tons. Such an object would cross the radius of the Earth within two hundredths of a second and produce a gravitational tidal signal in the frequency band of LIGO-Virgo-KAGRA. Needless to say, no such object was detected so far.

Within a decade, the LISA space observatory will expand gravitational wave detection to the frequency range between milli- and micro-Hertz and a smaller spacetime strain. This will usher in a new era of sensitivity to dark near-Earth objects in the asteroid mass range. It could also open the door to the detection of Unidentified Anomalous Phenomena (UAP) gravitationally, which the Galileo Project observatories are attempting to detect electromagnetically. Pulsar Timing Arrays(PTAs) probe a frequency range of a few nano-Hertz, but so-far they were only sensitive to the cumulative gravitational wave background at these frequencies – which constitute the noise floor for the detection of individual sources.

Gravitational wave detectors are the most exciting telescopes of the next millennium as they will open the door for detecting objects that we had never noticed before. As I showed in another recent paper, it is impossible to block or dissipate gravitational wave signals. They offer the optimal communication method, detectable through Earth or the Sun.

It is conceivable that extraterrestrial technological civilizations communicate in gravitational signals, and our failure to notice them so far is because traditional SETI relied on seeking electromagnetic signals with traditional telescopes. If so, the silence that triggered Fermi’s question: “Where is everybody?” stems from our blindness to gravitational signals at the appropriate frequency.

Aliens would choose a communication channel that does not interfere with the frequencies of the loudest natural sources of gravitational waves in the cosmos. These are black hole binaries of stellar mass – to which LIGO-Virgo-KAGRA is tuned, as well as supermassive black hole pairs – to which LISA and PTAs are tuned. In that case, gravitational-SETI will need to develop sensitivity in other frequency bands.

The main challenge in producing detectable gravitational signals is the requirement to move large masses at high speeds. To within an order of magnitude, the gravitational wave strain is of order the gravitational potential produced by the transmitter divided by the speed of light squared times the square of the characteristic speed by which its mass moves in units of the speed of light. For context, the gravitational wave strain produced by the nearest stellar binary, Alpha-Centauri A & B – as the two stars orbit each other every 80 years, is only of order 10^{-24} and extremely challenging to detect.

Five years ago, a team led by Marek Abramowicz published a paper on the possibility that an advanced technological civilization harvests energy from the supermassive (4 million solar-mass) black hole Sagittarius A* at the center of the Milky Way and uses it for communication. They found that a Jupiter-mass structure in the innermost stable circular orbit around the black hole would emit an unambiguous gravitational wave signal that could be observed by LISA.

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Bizarre and Outlandish Claims and Conspiracies of the Moon

There is little doubt that the Moon is one of the most fascinating objects in the night sky. It is also at the center of some of the most outrageous and bizarre claims and conspiracies on record, not least just why NASA has not returned since the last moon landing in December 1972. Some of these conspiracies suggest there are the remains of alien bases and technology on the Moon, while others go even further and suggest there is an extraterrestrial presence on our cosmic satellite. Some researchers have even suggested that the Moon is not a natural satellite at all, but some kind of mechanical construct designed and built at an unknown location and placed in orbit by an unknown intelligence.

The fact is, though, even without these conspiracies, the Moon is a celestial body full of anomalies. While some people might be familiar with them, before we explore some of these outrageous conspiracies and claims of our celestial satellite, it is worth quickly going over some of the truly anomalous facts about the Moon.

It is, for example, exactly 400 times smaller than the sun, and its distance from the Earth, relative to the overall distance to the sun, is also exactly 1/400th. It is worth noting that these figures are not approximate – they are exact. It is because of these astounding dimensions that total eclipses are experienced here on Earth. Moreover, if these dimensions were out in any way whatsoever, this wouldn’t be possible. Incidentally, we should also take note that the chances of these specific dimensions occurring naturally are zillions to one. What’s more, these figures and dimensions are not seen in any other known moon. Even its perfectly circular orbit is unique (most moons’ orbits are elliptical) and its rotation around the planet is such that one side permanently remains hidden from us.

Looking a little closer, the many craters on the lunar surface create further problems in our understanding of the Moon. These craters, of which there are many, are for the most part, very similar in depth, and relatively shallow at that. In terms of our understanding of modern science, these craters should be much more varied, with at least some showing greater depth at the impact point, which should be the outcome for a naturally formed rocky terrestrial body. Many researchers suggest that it is the absolute high velocity of the meteor strikes that creates these crater anomalies. However, the actual reason for this, at least according to some researchers, both inside and outside the mainstream, is because the Moon is not naturally occurring at all, but a hollow object with a metallic “casing” beneath an artificial rocky surface.  

Perhaps one of the most interesting considerations is how the Moon came to orbit the Earth in the first place. Accepted thinking suggests a small planet or large moon collided with Earth millions of years ago, causing the Moon to form out of the debris of such a collision, which then settled into its current orbit. However, not only because of the remarkable zillion-to-one dimensions and distances of the Moon we highlighted earlier but also because of several other anomalies, many people question just how true it is that the Moon was simply a “happy accident” and a product of coincidence. In fact, some people have even questioned if the Moon was purposely “placed” into orbit, perhaps even by an unknown intelligence. Author William Roy Shelton stated:

“It is important to remember that something had to put the moon in or near its current circular pattern around the Earth. It is very unlikely that any object just stumbles on the right combination of factors needed to help an object stay in orbit. ‘Something’ had to put the moon on its altitude, on its course and speed. The question is, what was that ‘something?”

Issac Asimov, a Russian professor of biochemistry, made similar comments when he wrote:

“… we cannot help but come to the conclusion that the Moon, by rights, ought not to be there. The fact that it is, is one of those strokes of luck almost too good to accept…Small planets, such as Earth, with weak gravitational fields, might well lack satellites…In general, then, when a planet does have satellites, those satellites are much smaller than the planet itself. Therefore, there would be every reason to suspect (the Moon) would be a tiny world, perhaps 30 miles…but it is a giant satellite, 2,160 miles in diameter. How is it, then, that tiny Earth has one?”

There are plenty of other people who have expressed similar sentiments. NASA scientist, Robin Brett stated that “it seems easier to explain the non-existence of the Moon than its existence,” while Irwin Shapiro from the Harvard-Smithsonian Center for Astrophysics offered that “the best explanation for the Moon is an observational error!”

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Dark Energy Doesn’t Exist, Proponents of Controversial New ‘Timescape’ Theory Claim

Groundbreaking new findings are challenging the existence of dark energy, based on research that suggests the uneven structure of the universe could provide an alternate explanation for its accelerating expansion.

A long-hypothesized repulsive force that overcomes gravity and accounts for the increasing rate of expansion of our universe, the mysterious “dark energy” astrophysicists believe to be affecting the universe at the largest scales remains elusive.

Now, a new theory dubbed the “timescape” model presents an alternative: that the observed acceleration of our universe is not the result of an unseen force in the cosmos, but could instead arise from the irregular distribution of matter within it.

The model, developed by a research team at the University of Canterbury in Christchurch, New Zealand, challenges long-held assumptions about the supposed invisible force driving the acceleration of cosmic expansion, and could potentially help astronomers resolve several anomalies that have long perplexed cosmologists.

Questioning Dark Energy’s Existence

Although long accepted as a fundamental force behind one of astronomy’s greatest mysteries, dark energy’s existence remains theoretical. The concept of a mysterious invisible force was initially introduced to help account for phenomena that the standard model of physics currently cannot explain.

However, many scientists have acknowledged the persistent inconsistencies the theory presents, which include what astronomers call the “Hubble tension,” where observed predicted rates of cosmic expansion differ from those proposed by models that conform to the standard model.

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NASA IDENTIFIES 17 POTENTIALLY HABITABLE EARTH-SIZED ICY WORLDS, INCLUDING TWO COSMIC NEARBY NEIGHBORS

NASA researchers say they have identified 17 potentially habitable icy worlds that are approximately Earth-sized, including two that reside in our cosmic backyard.

Similar to the icy moons of Jupiter (Europa) and Saturn (Enceladus) in our solar system, these worlds are believed to contain massive oceans underneath an icy outer shell, where a combination of tidal forces and radiation might enable the types of life found in the deepest parts of Earth’s oceans.

The researchers also said that these icy worlds may contain surface geysers that erupt some of that water into space, where human-made telescopes could scan those plumes for signs of extraterrestrial life.

Dating back to the discovery of the first exoplanet in 1995, most efforts to search for life on other planets have focused on rocky worlds like Earth that orbit within their host star’s habitable zone, where temperatures would permit liquid water to exist on the planet’s surface. That’s because virtually all life on Earth uses liquid water, and Earth is the only place we have definitively found life.

For a long time, it was also believed that virtually all life forms required sunlight. However, recent discoveries of life forms in the deepest parts of Earth’s oceans that thrive in complete darkness have changed those calculations.

Dubbed “extremophiles,” these hardy organisms replace the light energy most life forms receive from the sun with thermal energy spewed by volcanic vents on the ocean floor. They also receive vital nutrients and other organic compounds from these vents, both of which are also critical to life.

These discoveries have led astrobiologists to redefine where they search for life outside Earth. Two of the most tantalizing targets are Europa and Enceladus. Scientists theorize that the tidal forces of their host planets and other moons combined with radiation energy generate enough internal heat energy that these icy moons may have oceans of seawater beneath their icy shells.

In 2005, NASA’s Cassini mission spotted geysers of water erupting from the surface of Enceladus, lending strong support to those theories. The space agency is even evaluating missions designed to fly spacecraft through those plumes and collect samples of the oceans below.

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HAS DARK MATTER’S IDENTITY BEEN REVEALED? SCIENTISTS SEARCHING FOR MYSTERIOUS HYPOTHETICAL PARTICLE MAY SOON HAVE AN ANSWER

Scientists may be closing in on solving the mystery of dark matter, a hypothetical, nonluminous material that is believed to comprise a large majority of the mass in our universe, in new research that may link it to the existence of a hypothetical subatomic particle.

Among the primary questions scientists have about dark matter is what it could be made of. However, new research by an international team of astrophysicists proposes a possible candidate, meaning that this elusive cosmic material might be detectable in the form of a glow emanating from certain kinds of stars.

The research, conducted by astrophysicists at the universities of Amsterdam and Princeton, suggests that dark matter, which presently is believed to constitute around 85% of the matter in the universe, could be composed of hypothetical particles known as axions.

First proposed in the 1970s to resolve an unrelated problem involving neutrons, axions are of interest to dark matter researchers because if they possess a low mass within a certain range, they could be good candidates in the search for dark matter. Not only that, but they might help to potentially explain how and why dark matter has remained so elusive.

Axions are thought to weakly interact with known particles, which, like dark matter, makes them difficult to detect. That isn’t to say that scientists don’t have a good idea about where to look, since according to the recent findings, axions may be able to be converted into light in the presence of strong electromagnetic fields, thereby illuminating these invisible universal mysteries.

If this is correct, one of the best places to begin any search for axions—and potentially also for dark matter—is to look where the strongest magnetic fields in the universe are known to occur.

Astrophysicists are aware that regions around rotating neutron stars, otherwise known as pulsars, are prime candidates for the search. Possessing a mass comparable to our Sun, but packed into a space close to 100,000 times smaller, pulsars spin very rapidy and produce bright radio emissions along their rotational axis, thereby generating a powerful electromagnetic field.

If axions exist, then the powerful magnetic fields of pulsars make them the perfect place to search for them.

In their recent research, the international team of physicists and astronomers developed a theoretical framework that helped them understand how axions might be produced in these stellar regions, as well as how they might be converted into radio waves emitted by the rotation of pulsars.

Using computer simulations, the team was able to successfully model axion production around pulsars and predict the resulting additional radio signal that would be likely to indicate the presence of the otherwise invisible axions.

With this information, the team then used observations from 27 nearby pulsars, comparing their models to these real-life sources of cosmic radio waves. Despite their best attempts, however, the team was unable to find any conclusive evidence yet that points to the existence of the elusive axions.

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A CELESTIAL OBJECT “TOO LARGE TO EXIST” HAS BEEN DETECTED BY ASTRONOMERS, UPENDING PAST THEORIES ON PLANETARY FORMATION

Researchers say the discovery of a planet too large for its nearest star is challenging existing theories about the dynamics of planetary formation, according to recent findings.

The discovery, reported by researchers at Penn State University, involves a massive planet orbiting LHS 3154, a star that is around nine times smaller than our Sun, and thereby also much cooler.

By comparison, the newly named planet, LHS 3154b, which orbits it is more than 13 times the size of Earth, which planetary scientists say should not be possible.

Put into context, the mass ratio of the planet to its host star is greater than 100 times that of Earth and the Sun, making LHS 3154b the largest planet ever discovered orbiting an ultracool dwarf star and, more fundamentally, a planet too large to easily fit within current models about how such celestial objects form.

Suvrath Mahadevan, the Verne M. Willaman Professor of Astronomy and Astrophysics at Penn State, said he and his colleagues were surprised by the discovery.

“We wouldn’t expect a planet this heavy around such a low-mass star to exist,” Mahadevan said in a press release describing the new findings.

Generally, once a star is formed, gas and dust surrounding it will form a protoplanetary disk, which will eventually form planets over long periods. However, the disk around LHS 3154 does not have enough solid mass to facilitate planetary formation in the case of an object like LHS 3154b, Mahadevan says.

“But it’s out there,” he adds, “so now we need to reexamine our understanding of how planets and stars form.”

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Woke Stars Shine: Colorado College Astrophysics Prof Claims the Study of Space Is Racist, Sexist

Colorado College astrophysics professor Natalie Gosnell says her field is engrossed in “white supremacy” and sexism, adding that language used to describe the cosmos is “very violent and hyper-masculine.”

Gosnell, who is dismayed over society separating “math” and “creativity” into two categories, says dichotomizing these two characteristics is rooted in systemic racism and sexism, according to a report by Colorado College News.

“As an astrophysicist, I’m a product of institutions that are steeped in systemic racism and white supremacy,” Gosnell told the student newspaper.

“The tenets of white supremacy that show up [in physics] of individualism and exceptionalism and perfectionism… it’s either-or thinking, and there’s no subtlety, there’s no gray area,” the professor added. “All of this manifests in the way that we think about our research, and what counts as good research, what counts as important research?”

Colorado College News concurred, adding that “most of Gosnell’s career has been dictated by the hyper-masculine world of astrophysics.”

When a star transfers its mass to an orbiting star, for example, this process is discussed “through a violent, hyper-masculine lens,” the student newspaper said, noting that the phenomenon has been referred to as a “Vampire star” or “Cannibal star,” with Gosnell adding that these stars are also viewed as the “bad boys” of the universe.

“I think because science and art have been so separated, and there’s — systemic issues within science, the metaphors that are often chosen [to discuss science] are very violent and hyper-masculine,” the professor said.

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