Tag: planet

Posted on by

Could a Mystery Planet End Life on Earth?

A terrestrial planet hovering between Mars and Jupiter would be able to push Earth out of the solar system and wipe out life on this planet, according to a UC Riverside experiment at the University of California Riverside. 

UCR astrophysicist Stephen Kane explained that his experiment was meant to address two notable gaps in planetary science. 

The first is the gap in our solar system between the size of terrestrial and giant gas planets. The largest terrestrial planet is Earth, and the smallest gas giant is Neptune, which is four times wider and 17 times more massive than Earth. There is nothing in between. 

“In other star systems there are many planets with masses in that gap. We call them super-Earths,” Kane said. 
The other gap is in location, relative to the sun, between Mars and Jupiter. “Planetary scientists often wish there was something in between those two planets. It seems like wasted real estate,” he said. 

These gaps could offer important insights into the architecture of our solar system, and into Earth’s evolution. To fill them in, Kane ran dynamic computer simulations of a planet between Mars and Jupiter with a range of different masses, and then observed the effects on the orbits of all other planets. 

The results, published in the Planetary Science Journal, were mostly disastrous for the solar system. “This fictional planet gives a nudge to Jupiter that is just enough to destabilize everything else,” Kane said. “Despite many astronomers having wished for this extra planet, it’s a good thing we don’t have it.”

Jupiter is much larger than all the other planets combined; its mass is 318 times that of Earth, so its gravitational influence is profound. If a super-Earth in our solar system, a passing star, or any other celestial object disturbed Jupiter even slightly, all other planets would be profoundly affected.

Depending on the mass and exact location of a super-Earth, its presence could ultimately eject Mercury and Venus as well as Earth from the solar system. It could also destabilize the orbits of Uranus and Neptune, tossing them into outer space as well. 

The super-Earth would change the shape of this Earth’s orbit, making it far less habitable than it is today, if not ending life entirely.

If Kane made the planet’s mass smaller and put it directly in between Mars and Jupiter, he saw it was possible for the planet to remain stable for a long period of time. But small moves in any direction and, “things would go poorly,” he said. 

The study has implications for the ability of planets in other solar systems to host life. Though Jupiter-like planets, gas giants far from their stars, are only found in about 10% of the time, their presence could decide whether neighboring Earths or super-Earths have stable orbits. 

These results gave Kane a renewed respect for the delicate order that holds the planets together around the sun. “Our solar system is more finely tuned than I appreciated before. It all works like intricate clock gears. Throw more gears into the mix and it all breaks,” Kane said. 

The late Zecharia Sitchin explained the asteroid belt between Mars and Jupiter as resulting from the destruction of a planet known as Tiamat after being struck by a rogue planet called Niburu. The story can be found, he said, in the cuneiform texts of Sumeria. Similarly, in a 1988 book, Catastrophism and the Old Testament, author Donald W. Patten theorized that a planet called ‘Astra’ had collided with Mars after breaking into pieces, much as the comet Shoemaker-Levy which hit Jupiter in 1994.

Many esoteric traditions, such as Theosophy, have long held that the asteroid belt is the aftermath of a collision between a planet known as Maldek and Mars. Many such sources claim Maldek was destroyed by the nukes of a mad civilization.

Usually discussed under the heading ‘Phaeton,’ this hypothetical world was also called the ‘fifth planet.’ The idea being that the solar system originally had just five planets.The notion that the asteroid belt resulted from a planetary collision has also been called the ‘Disruption Theory,’ though it has been summarily rejected by academia. New evidence, however, is forcing science to reconsider many ideas once dismissed as fringe.

In December, 2019 a new study led by University of Oklahoma astrophysicist Matthew S. Clements published in the journal Monthly Notices of the Royal Astronomical Society, took a new approach. Entitled “A record of the final phase of giant planet migration fossilized in the asteroid belt’s orbital structure,” the paper challenged the “Nice Model” , the standard theory for the dynamical evolution of the Solar System. According to Clements and his colleagues a comprehensive new analysis of orbital data indeed suggests that the asteroid belt should be viewed as the fossil record of a destroyed fifth planet (https://academic.oup.com/mnrasl/article/492/1/L56/5672641).

AR #107

Ancient Nukes on Mars

by Martin Ruggles

Posted on by

Colossal Black Holes Dance at Heart of Galaxy

Astronomers find evidence for the tightest-knit supermassive black hole duo observed to date

By Whitney Clavin

Locked in an epic cosmic waltz 9 billion light years away, two supermassive black holes appear to be orbiting around each other every two years. The two giant bodies each have masses that are hundreds of millions of times larger than that of our sun, and the objects are separated by a distance roughly 50 times that which separates our sun and Pluto. When the pair merge in roughly 10,000 years, the titanic collision is expected to shake space and time itself, sending gravitational waves across the universe.

A Caltech-led team of astronomers has discovered evidence for this scenario taking place within a fiercely energetic object known as a quasar. Quasars are active cores of galaxies in which a supermassive black hole is siphoning material from a disk encircling it. In some quasars, the supermassive black hole creates a jet that shoots out at near the speed of light. The quasar observed in the new study, PKS 2131-021, belongs to a subclass of quasars called blazars in which the jet is pointing toward the Earth. Astronomers already knew quasars could possess two orbiting supermassive black holes, but finding direct evidence for this has proved difficult.


Reporting in The Astrophysical Journal Letters, the researchers argue that PKS 2131-021 is a very rare candidate for a pair of supermassive black holes caught in the act of merging. The first candidate pair, within a quasar called OJ 287, orbit each other at greater distances, circling every nine years versus the two years it takes for the PKS 2131-021 pair to complete an orbit.


The telltale evidence came from radio observations of PKS 2131-021 that span 45 years. According to the study, a powerful jet emanating from one of the two black holes within PKS 2131-021 is shifting back and forth due to the pair’s orbital motion. This causes periodic changes in the quasar’s radio-light brightness. Five different observatories registered these oscillations, including Caltech’s Owens Valley Radio Observatory (OVRO), the University of Michigan Radio Astronomy Observatory (UMRAO), MIT’s Haystack Observatory, the National Radio Astronomy Observatory (NRAO), Metsähovi Radio Observatory in Finland, and NASA’s Wide-field Infrared Survey Explorer (WISE) space satellite.


The combination of the radio data yields a nearly perfect sinusoidal light curve unlike anything observed from quasars before.


“When we realized that the peaks and troughs of the light curve detected from recent times matched the peaks and troughs observed between 1975 and 1983, we knew something very special was going on,” says Sandra O’Neill, lead author of the new study and an undergraduate student at Caltech who is mentored by Tony Readhead, Robinson Professor of Astronomy, Emeritus.


Most, if not all, galaxies possess monstrous black holes at their cores, including our own Milky Way galaxy. When galaxies merge, their black holes “sink” to the middle of the newly formed galaxy and eventually join together to form an even more massive black hole. As the black holes spiral toward each other, they increasingly disturb the fabric of space and time, sending out gravitational waves, which were first predicted by Albert Einstein more than 100 years ago.

 

AR #114

Gravity’s Riddle

by Susan Martiinez, Ph.D.

 

Posted on by

‘Dark’ Free-Floating Black Hole Detected

By Robert Sanders

Astronomers may have discovered the first free-floating black hole in the Milky Way galaxy, thanks to a technique called gravitational microlensing. With new observations, they hope to find many more such ghost stars.

If, as astronomers believe, the death of large stars leave behind black holes, there should be hundreds of millions of them scattered throughout the Milky Way galaxy. The problem is, isolated black holes are invisible.
Now, a team led by University of California, Berkeley, astronomers has for the first time discovered what may be a free-floating black hole by observing the brightening of a more distant star as its light was distorted by the object’s strong gravitational field — so-called gravitational microlensing.


The team, led by graduate student Casey Lam and Jessica Lu, a UC Berkeley associate professor of astronomy, estimates that the mass of the invisible compact object is between 1.6 and 4.4 times that of the sun. Because astronomers think that the leftover remnant of a dead star must be heavier than 2.2 solar masses in order to collapse to a black hole, the UC Berkeley researchers caution that the object could be a neutron star instead of a black hole. Neutron stars are also dense, highly compact objects, but their gravity is balanced by internal neutron pressure, which prevents further collapse to a black hole.


Whether a black hole or a neutron star, the object is the first dark stellar remnant — a stellar “ghost” — discovered wandering through the galaxy unpaired with another star.


“This is the first free-floating black hole or neutron star discovered with gravitational microlensing,” Lu said. “With microlensing, we’re able to probe these lonely, compact objects and weigh them. I think we have opened a new window onto these dark objects, which can’t be seen any other way.”


Determining how many of these compact objects populate the Milky Way galaxy will help astronomers understand the evolution of stars — in particular, how they die — and of our galaxy, and perhaps reveal whether any of the unseen black holes are primordial black holes, which some cosmologists think were produced in large quantities during the Big Bang.


The analysis by Lam, Lu and their international team has been accepted for publication in The Astrophysical Journal Letters. Notably, a competing team from the Space Telescope Science Institute (STScI) in Baltimore analyzed the same microlensing event and claims that the mass of the compact object is closer to 7.1 solar masses and indisputably a black hole. A paper describing the analysis by the STScI team, led by Kailash Sahu, has been accepted for publication in The Astrophysical Journal.

 

AR #64

Human Evolution and the Cygnus Connection By Greg Little

 

Posted on by

Can a Planet Have a Mind of its Own?

The collective activity of life—all of the microbes, plants, and animals—have changed planet Earth.

Take, for example, plants: plants ‘invented’ a way of undergoing photosynthesis to enhance their own survival, but in so doing, released oxygen that changed the entire function of our planet. This is just one example of individual lifeforms performing their own tasks, but collectively having an impact on a planetary scale.

If the collective activity of life—known as the biosphere—can change the world, could the collective activity of cognition, and action based on this cognition, also change a planet? Once the biosphere evolved, Earth took on a life of its own. If a planet with life has a life of its own, can it also have a mind of its own?

These are questions posed by Adam Frank, the Helen F. and Fred H. Gowen Professor of Physics and Astronomy at the University of Rochester, and his colleagues David Grinspoon at the Planetary Science Institute and Sara Walker at Arizona State University, in a paper published in the International Journal of Astrobiology. Their self-described “thought experiment” combines current scientific understanding about the Earth with broader questions about how life alters a planet. In the paper, the researchers discuss what they call “planetary intelligence”—the idea of cognitive activity operating on a planetary scale—to raise new ideas about the ways in which humans might tackle global issues such as climate change.

As Frank says, “If we ever hope to survive as a species, we must use our intelligence for the greater good of the planet.”

An ‘immature technosphere’

Frank, Grinspoon, and Walker draw from ideas such as the Gaia hypothesis—which proposes that the biosphere interacts strongly with the non-living geological systems of air, water, and land to maintain Earth’s habitable state—to explain that even a non-technologically capable species can display planetary Intelligence. The key is that the collective activity of life creates a system that is self-maintaining.

For example, Frank says, many recent studies have shown how the roots of the trees in a forest connect via underground networks of fungi known as mycorrhizal networks. If one part of the forest needs nutrients, the other parts send the stressed portions the nutrients they need to survive, via the mycorrhizal network. In this way, the forest maintains its own viability.

Right now, our civilization is what the researchers call an “immature technosphere,” a conglomeration of human-generated systems and technology that directly affects the planet but is not self-maintaining. For instance, the majority of our energy usage involves consuming fossil fuels that degrade Earth’s oceans and atmosphere. The technology and energy we consume to survive are destroying our home planet, which will, in turn, destroy our species.

To survive as a species, then, we need to collectively work in the best interest of the planet.

But, Frank says, “we don’t yet have the ability to communally respond in the best interests of the planet. There is intelligence on Earth, but there isn’t planetary intelligence.”

  • Stage 1 – Immature biosphere: characteristic of very early Earth, billions of years ago and  before a technological species, when microbes were present but vegetation had not yet come about. There were few global feedbacks because life couldn’t exert forces on Earth’s atmosphere, hydrosphere, and other planetary systems.
  • Stage 2 – Mature biosphere: characteristic of Earth, also before a technological species, from about 2.5 billion to 540 million years ago. Stable continents formed, vegetation and photosynthesis developed, oxygen built up in the atmosphere, and the ozone layer emerged. The biosphere exerted a strong influence on the Earth, perhaps helping to maintain Earth’s habitability.
  • Stage 3 – Immature technosphere: characteristic of Earth now, with interlinked systems of communication, transportation, technology, electricity, and computers. The technosphere is still immature, however, because it is not integrated into other Earth systems, such as the atmosphere. Instead, it draws matter and energy from Earth’s systems in ways that will drive the whole into a new state that likely doesn’t include the technosphere itself. Our current technosphere is, in the long run, working against itself.
  • Stage 4 – Mature technosphere: where Earth should aim to be in the future, Frank says, with technological systems in place that benefit the entire planet, including globally harvesting energy in forms like solar that do not harm the biosphere. The mature technosphere is one that has co-evolved with the biosphere into a form that allows both the technosphere and the biosphere to thrive.

“Planets evolve through immature and mature stages, and planetary intelligence is indicative of when you get to a mature planet,” Frank says. “The million-dollar question is figuring out what planetary intelligence looks like and means for us in practice because we don’t know how to move to a mature technosphere yet.”

The complex system of planetary intelligence

Although we don’t yet know specifically how planetary intelligence might manifest itself, the researchers note that a mature technosphere involves integrating technological systems with Earth through a network of feedback loops that make up a complex system.

Put simply, a complex system is anything built from smaller parts that interact in such a fashion that the overall behavior of the system is entirely dependent on the interaction. That is, the sum is more than the whole of its parts. Examples of complex systems include forests, the Internet, financial markets, and the human brain.

By its very nature, a complex system has entirely new properties that emerge when individual pieces are interacting. It is difficult to discern the personality of a human being, for instance, solely by examining the neurons in her brain.

That means it is difficult to predict exactly what properties might emerge when individuals form a planetary intelligence. However, a complex system like planetary intelligence will, according to the researchers, have two defining characteristics: it will have emergent behavior and will need to be self-maintaining.

“The biosphere figured out how to host life by itself billions of years ago by creating systems for moving around nitrogen and transporting carbon,” Frank says. “Now we have to figure out how to have the same kind of self-maintaining characteristics with the technosphere.”

The search for extraterrestrial life

Despite some efforts, including global bans on certain chemicals that harm the environment and a move toward using more solar energy, “we don’t have planetary intelligence or a mature technosphere yet,” he says. “But the whole purpose of this research is to point out where we should be headed.”

Raising these questions, Frank says, will not only provide information about the past, present, and future survival of life on Earth but will also help in the search for life and civilizations outside our solar system. Frank, for instance, is the principal investigator on a NASA grant to search for technosignatures of civilizations on planets orbiting distant stars.

“We’re saying the only technological civilizations we may ever see—the ones we should expect to see—are the ones that didn’t kill themselves, meaning they must have reached the stage of a true planetary intelligence,” he says. “That’s the power of this line of inquiry: it unites what we need to know to survive the climate crisis with what might happen on any planet where life and intelligence evolve.”

Toward a mature technosphere

The researchers posit four stages of Earth’s past and possible future to illustrate how planetary intelligence might play a role in humanity’s long-term future. They also show how these stages of evolution driven by planetary intelligence may be a feature of any planet in the galaxy that evolves life and a sustainable technological civilization.

Issue #122
Is Anyone Home?

Posted on by

Planet Orbiting Proxima Centauri

Proxima Centauri

A team of astronomers using the European Southern Observatory’s Very Large Telescope (ESO’s VLT) in Chile have found evidence of another planet orbiting Proxima Centauri, the closest star to our Solar System. This candidate planet is the third detected in the system and the lightest yet discovered orbiting this star. At just a quarter of Earth’s mass, the planet is also one of the lightest exoplanets ever found.

“The discovery shows that our closest stellar neighbor seems to be packed with interesting new worlds, within reach of further study and future exploration,” explains João Faria, a researcher at the Instituto de Astrofísica e Ciências do Espaço, Portugal and lead author of the study published today in Astronomy & Astrophysics. Proxima Centauri is the closest star to the Sun, lying just over four light-years away.

The newly discovered planet, named Proxima d, orbits Proxima Centauri at a distance of about four million kilometers, less than a tenth of Mercury’s distance from the Sun. It orbits between the star and the habitable zone — the area around a star where liquid water can exist at the surface of a planet — and takes just five days to complete one orbit around Proxima Centauri.

The star is already known to host two other planets: Proxima b, a planet with a mass comparable to that of Earth that orbits the star every 11 days and is within the habitable zone, and candidate Proxima c, which is on a longer five-year orbit around the star.

Proxima b was discovered a few years ago using the HARPS instrument on ESO’s 3.6-metre telescope. The discovery was confirmed in 2020 when scientists observed the Proxima system with a new instrument on ESO’s VLT that had greater precision, the Echelle SPectrograph for Rocky Exoplanets and Stable Spectroscopic Observations (ESPRESSO). It was during these more recent VLT observations that astronomers spotted the first hints of a signal corresponding to an object with a five-day orbit. As the signal was so weak, the team had to conduct follow-up observations with ESPRESSO to confirm that it was due to a planet, and not simply a result of changes in the star itself.

“After obtaining new observations, we were able to confirm this signal as a new planet candidate,” Faria says. “I was excited by the challenge of detecting such a small signal and, by doing so, discovering an exoplanet so close to Earth.”  

At just a quarter of the mass of Earth, Proxima d is the lightest exoplanet ever measured using the radial velocity technique, surpassing a planet recently discovered in the L 98-59 planetary system. The technique works by picking up tiny wobbles in the motion of a star created by an orbiting planet’s gravitational pull. The effect of Proxima d’s gravity is so small that it only causes Proxima Centauri to move back and forth at around 40 centimeters per second (1.44 kilometres per hour).

“This achievement is extremely important,” says Pedro Figueira, ESPRESSO instrument scientist at ESO in Chile. “It shows that the radial velocity technique has the potential to unveil a population of light planets, like our own, that are expected to be the most abundant in our galaxy and that can potentially host life as we know it.”

“This result clearly shows what ESPRESSO is capable of and makes me wonder about what it will be able to find in the future,” Faria adds.

ESPRESSO’s search for other worlds will be complemented by ESO’s Extremely Large Telescope (ELT), currently under construction in the Atacama Desert, which will be crucial to discovering and studying many more planets around nearby stars.

More information

This research was presented in the paper “A candidate short-period sub-Earth orbiting Proxima Centauri” (doi:10.1051/0004-6361/202142337) to appear in Astronomy & Astrophysics.

Issue #122
Is Anyone Home?

Posted on by

Strange Space Object Spotted

Unlike Anything Astronomers Have Ever Seen Before

A team mapping radio waves in the Universe has discovered something unusual that releases a giant burst of energy three times an hour, and it’s unlike anything astronomers have seen before.

The team who discovered it think it could be a neutron star or a white dwarf—collapsed cores of stars—with an ultra-powerful magnetic field.

Spinning around in space, the strange object sends out a beam of radiation that crosses our line of sight, and for a minute in every twenty, is one of the brightest radio sources in the sky.

An animation describing the discovery, the behavior of the object and what it might look like. Credit: ICRAR.

Astrophysicist Dr Natasha Hurley-Walker, from the Curtin University node of the International Center for Radio Astronomy Research, led the team that made the discovery.

“This object was appearing and disappearing over a few hours during our observations,” she said.

“That was completely unexpected. It was kind of spooky for an astronomer because there’s nothing known in the sky that does that.

“And it’s really quite close to us—about 4000 light years away. It’s in our galactic backyard.”

Issue #114
Is Anyone Home?

 

Posted on by

The Asteroid Shoving Mission

For those who think that Atlantis was brought down by a rock from space, the prospect of history repeating itself has long been a cause for worry, if not deep dread. Ever since comet Shoemaker-Levy crashed into Jupiter in 1994 with a force, that would, if directed at Earth, have destroyed our planet, many serious people, not just Hollywood heroes, have been awakened to the threat. And given the presence of thousands of such potentially deadly bolides in our solar neighborhood, it is clear that a real threat to continued life on Earth exists. The big question is what do we do about it? And now, we are happy to report, a new effort has been launched by NASA to push back against the threat from space.

Just in case some day, a threatening asteroid were to be found heading this way, the Double Asteroid Redirection Test (DART) mission, launched in November, 2021, will deploy a technology that, it is hoped, could save the planet, by preventing a hazardous asteroid from ever making it to Earth. DART is the first demonstration of the kinetic impactor technique to change the motion of an asteroid in space—in other words, ‘shoving’ the asteroid into a non threatening trajectory by crashing into it. In September 2022, the probe is intended to crash into the minor-planet moon Dimorphos of the double asteroid Didymos.

Dimorphos is NOT a threat to Earth, but the asteroid belt is believed to be a perfect testing ground to see if intentionally crashing a spacecraft into an asteroid is an effective way to change its course, should an Earth-threatening asteroid be discovered in the future. While, according to NASA, no ‘known’ asteroid larger than 140 meters in size has a significant chance to hit Earth for the next 100 years, as of October 2021, only about 40 percent of such asteroids have been found.

Ironically, while some seek to shove asteroids around to protect Earth, others have different ideas. One scheme under consideration involves nudging a football-field-sized asteroid into orbit around earth where it would be easier to exploit. Asteroids, it is thought, could prove virtual gold mines. Certainly plenty of platinum is to be found (all platinum on earth comes from space rocks), to say nothing of water, which could be turned into hydrogen fuel and oxygen for future interplanetary missions. Many asteroids are as much a 20% water.

Posted on by

Has Planet 9 Already Been Spotted?

In 2016, astronomers, Konstantin Batygin and Michael Brown published a prediction—not yet a discovery—of a possible new planet lurking at the far periphery of the solar system, in an elongated path far beyond Pluto. Ever since, the hunt has been on for the missing planet. But, could the search for planet nine have already succeeded? Has a mysterious undiscovered planet, long envisioned somewhere beyond the orbit of Neptune by astronomers and alternative researchers alike have already made an appearance to probes from Earth, but gone unnoticed? A respected British Astronomer thinks so.

So far, no one has actually seen the theoretical planet. But, then again, maybe they have. Astronomer Michael Rowan-Robinson of Imperial College London has been combing through the data from a 1983 mission, in which he participated, and he now says he has located the illusive planet, or at least the part of the sky where it could be found. The data is taken from Infrared Astronomical Satellite (IRAS) readings.

Rowan-Robinson has published the findings of his research in arXiv, an open-access archive for articles on physics, mathematics, and computer science (https://arxiv.org/abs/2111.03831).

Observations of the planet Neptune have long led astronomers to believe another planet must be out there and interfering with its orbit. Pluto was found in 1930 by looking at objects on photographic plates, but it wasn’t large enough to account for the movement of Neptune. That anomalous movement is what arouses speculation about ‘planet 9’ (‘planet 10’, if you count Pluto)–aka, ‘Planet X.’ Arguments over the possibility of another planet beyond the orbit of Neptune have raged for over a century. As early as 1906, when he established The Lowell observatory in Flagstaff, Arizona, famed astronomer Percival Lowell was looking for his own version of Planet X, which he believed was indicated by the observed perturbations in the orbit of Neptune.

Studies of the sort have come from all parts of the world. In December 2015 the Journal of Astronomy of Astrophysics, published two Swedish papers claiming a new, relatively large, body out in the neighborhood of Pluto. Astronomer Wouter Vlemmings, co-author of both studies, reported observation of an object moving against the background stars which was then dubbed Gna, after a swift Nordic deity who delivers messages for Frigg, the goddess of wisdom. In 2018, Brazilian astronomer Rodney Gomes reported that his calculations showed the presence of a planet four times the size of Earth lying beyond the orbit of Pluto. Later, Carlos and Raul de la Fuente of Spain re-examined the data and concluded that, not only, must there be a planet such as proposed by Gomes, but that there must be an even bigger planet still further out which is influencing the first one. That such objects could have remained undiscovered for so long, we were told, is quite understandable.

Late in 2021 a team of space scientists published a paper in The Annual Review of Astronomy and Astrophysics suggesting that there may be an Earth- or Mars-sized planet orbiting beyond Neptune. They further suggest that simulations of the creation of the solar system show that such a planet may have been pushed from the outer regions of the solar system by Neptune and Uranus. Over the years, there have been several reports of large objects in the Kuiper belt (ie., Pluto and Eris), but until the Batygin and Brown discovery, none have been heavy enough to contend for the title of ‘Planet X’.