One of the most intriguing questions in astronomy is whether there is life beyond Earth. Many scientists are searching for signs of life on planets orbiting distant stars, hoping to find evidence of biospheres similar to our own.
However, a new study suggests that some of these planets may face a serious threat from their own moons: instability.
The study, published in journal Monthly Notices of the Royal Astronomical Society, examines how the gravitational interactions between a planet and its moons can affect the stability of the moons’ orbits over time.
The researchers found that if a planet has multiple large moons, like Jupiter or Saturn, their orbits can become chaotic and eventually collide with each other or with the planet. This could have devastating consequences for any life on the planet or its moons.
The researchers used computer simulations to model different scenarios of planetary systems with multiple large moons. They varied parameters such as the number and size of the moons, their orbital distances and eccentricities, and their initial orbital phases.
They found that in most cases, the moons’ orbits became unstable within a few billion years, leading to collisions or ejections from the system.
The collisions could produce huge amounts of debris that would rain down on the planet or its remaining moons, potentially causing mass extinctions or sterilization.
The ejections could also alter the climate and habitability of the planet or its moons by changing their orbital distances and periods. For example, if Earth’s moon were ejected from its orbit, Earth would lose its tides and seasons and experience more extreme temperature variations.
The researchers estimated that about 10 percent of exoplanets with multiple large moons could experience instability within 10 billion years, which is roughly the age of our galaxy. This means that many potentially habitable worlds could be rendered uninhabitable by their own moons.
However, not all planetary systems with multiple large moons are doomed to instability. The researchers identified some factors that could increase the stability of such systems, such as having fewer and smaller moons, having more circular and coplanar orbits, and having resonant orbital configurations (such as when one moon completes two orbits for every one orbit of another moon). These factors could help maintain stable gravitational balances between the planet and its moons.
One example of a stable system with multiple large moons is our own solar system. The researchers found that none of our giant planets’ moons are likely to become unstable within 10 billion years.
This is partly because our giant planets have relatively few large moons (four each for Jupiter and Saturn), which are mostly in resonant orbits (such as Io-Europa-Ganymede for Jupiter). Moreover, our giant planets are far enough from each other that they do not perturb each other’s moon systems significantly.
The study highlights how complex and dynamic planetary systems can be over long timescales. It also shows how important it is to consider not only planets but also their satellites when searching for extraterrestrial life.
While some planets may seem promising at first glance based on their size and distance from their star (the so-called “habitable zone”), they may actually be hostile to life due to their unstable moon systems.
There’s one last place Planet Nine could be hiding
A study recently submitted to The Astronomical Journal
continues to search for the elusive Planet Nine (also called Planet X),
which is a hypothetical planet that potentially orbits in the outer
reaches of the solar system and well beyond the orbit of the dwarf
The goal of this study, which is available on the pre-print server arXiv,
was to narrow down the possible locations of Planet Nine and holds the
potential to help researchers better understand the makeup of our solar
system, along with its formation and evolutionary processes. So, what
was the motivation behind this study regarding narrowing down the
location of a potential Planet 9?
Dr. Mike Brown, who is a Richard and Barbara Rosenberg Professor of
Astronomy at Caltech and lead author of the study, tells Universe Today,
“We are continuing to try to systematically cover all of the regions of
the sky where we predict Planet Nine to be. Using data from Pan-STARRS
allowed us to cover the largest region to date.”
Pan-STARRS, which stands for Panoramic Survey Telescope and Rapid
Response System, is a collaborative astronomical observation system
located at Haleakala Observatory and operated by the University of
Hawai’i Institute of Astronomy. For the study, the researchers used data
from Data Release 2 (DR2) with the goal of narrowing down the possible
location of Planet Nine based on findings from past studies.
In the end, the team narrowed down possible locations of Planet Nine
by eliminating approximately 78% of possible locations that were
calculated from previous studies. Additionally, the researchers also
provided new estimates for the approximate semimajor axis (measured in
astronomical units, AU) and Earth-mass size of Planet Nine at 500 and
6.6, respectively. So, what are the most significant results from this
study, and what follow-up studies are currently being conducted or
“While I would love to say that the most significant result
was finding Planet Nine, we didn’t,” Dr. Brown tells Universe Today. “So
instead, it means that we have significantly narrowed the search area.
We’ve now surveyed approximately 80% of the regions where we think
Planet Nine might be.”
In terms of follow-up studies, Dr.
Brown tells Universe Today, “I think that the LSST is the most likely
survey to find Planet Nine. When it comes online in a year or two it
will quickly cover much of the search space and, if Planet Nine is
there, find it.”
LSST stands for Legacy Survey of Space and Time, and is an
astronomical survey currently scheduled as a 10-year program to study
the southern sky and take place at the Vera C. Rubin Observatory in
Chile, which is presently under construction.
Objectives for LSST include studying identifying near-Earth asteroids
(NEAs) and small planetary bodies within our solar system, but also
include deep space studies, as well. These include investigating the
properties of dark matter and dark energy and the evolution of the Milky
Way galaxy. But what is the importance of finding Planet Nine?
Dr. Brown tells Universe Today, “This would be the 5th
largest planet of our solar system and the only one with a mass between
Earth and Uranus. Such planets are common around other stars, and we
would suddenly have a chance to study one in our own solar system.”
Scientists began hypothesizing the existence of Planet Nine shortly
after the discovery of Neptune in 1846, including an 1880 memoir
authored by D. Kirkwood and later a 1946 paper authored by American
astronomer, Clyde Tombaugh, who was responsible for discovering Pluto in
More recent studies include studies from 2016 and 2017 presenting
evidence for the existence of Planet Nine, the former of which was
co-authored by Dr. Brown.
This most recent study marks the
most complete investigation of narrowing down the location of Planet
Nine, which Dr. Brown has long-believed exists, telling Universe Today,
“There are too many separate signs that Planet Nine is there. The solar
system is very difficult to understand without Planet Nine.”
He continues by telling Universe Today that “…Planet Nine explains
many things about orbits of objects in the outer solar system that would
be otherwise unexplainable and would each need some sort of separate
“The cluster of the directions of the orbits is the best know, but
there is also the large perihelion distances of many objects, existence
of highly inclined and even retrograde objects, and the high abundance
of very eccentric orbits which cross inside the orbit of Neptune. None
of these should happen in the solar system, but all are easily
explainable as an effect of Planet Nine.”
Michael E. Brown et al, A Pan-STARRS1 Search for Planet Nine, arXiv (2024). DOI: 10.48550/arxiv.2401.17977
‘October Surprise’: Russia To Launch Nukes in Space
The ‘national security threat’ announced on Wednesday is
about Russia planning to launch nuclear weapons in space, causing some
to speculate whether it’s really an election year ploy.
The panic began when House Intelligence Committee Chair Mike Turner
(R-Ohio) asked President Biden to declassify information about a
“serious national security threat”.
Modernity.news reports: The weapon would reportedly be designed to be used to take out satellites.
Speaker Mike Johnson (R-La.) responded by telling reporters he wanted “to assure the American people, there is no need for public alarm.”
The big, scary threat is serious business and involves a space-based nuke controlled by evil dictator Putin, but it’s also “not an immediate crisis,” according to what three members of the U.S. House Intelligence Committee have told Politico.
Okay, then. Just for election season, is it?
Zero Hedge reports: “So, the question is – was this:
a) a distraction from Biden’s broken brain, or
2) a last desperate attempt to get more funding for anything-but-the-US-border, or
iii) a path to pitching Putin as the uber-bad-guy again after his interview with Tucker Carlson.”
Just by coincidence, Mike Turner recently returned from Ukraine having lobbied for billions more in weapons and aid for Zelensky’s government.
Some questioned the timing, suggesting it might all be a deep state plot to keep American voters afraid when they hit the ballot box.
Speculation will now rage as to whether this is “the event,” real or imagined, that billionaires and elitists the world over have been building underground survival bunkers in preparation for.
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