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The Habitable Worlds Observatory Could See Lunar and Solar ‘Exo-Eclipses’

May 21st, 2024

A future space observatory could use exo-eclipses to tease out exomoon populations.

If you’re like us, you’re still coming down from the celestial euphoria that was last month’s total solar eclipse. The spectacle of the Moon blocking out the Sun has also provided astronomers with unique scientific opportunities in the past, from the discovery of helium to proof for general relativity. Now, eclipses in remote exoplanetary systems could aid in the hunt for elusive exomoons.

A recent study out of the University of Michigan in partnership with Johns Hopkins APL and the Department of Physics and the Kavli Institute for Astrophysics and Space Research at the Massachusetts Institute of Technology entitled Exomoons & Exorings with the Habitable Worlds Observatory I: On the Detection of Earth-Moon Analog Shadows & Eclipses looks to use a future mission to hunt for eclipses, transits and occultations in distant systems.

Hunting for Exo-Moons

“HWO is likely to be able to detect exomoons using a variety of detection methods, unlike existing observatories,” Mary Anne Limbach (University of Michigan) lead author on the study told Universe Today. “In a system where we detect an exomoon via an exo-eclipse, we might be able to observe other signatures, such as light from the moon within the combined reflected light spectrum of the moon and the planet.”

The proposed Habitable Worlds Observatory (HWO) was derived from the LUVOIR-B (Large Ultraviolet Optical and Infrared explorer) concept. This was highlighted in the Astro2020 Decadal Survey for space-based astronomy. HWO would work from the Sun-Earth L2 Lagrange point (the current home for Euclid and JWST), and launch on either an SLS or Falcon Heavy sometime in the mid-2030s. HWO would employ a free-flying ‘star-shield,’ allowing it to observe exoplanets orbiting stars directly. But what’s really enticing to observers is the idea of seeing large moons orbiting said planets. Thus far, claims of exomoon detections such as Kepler-1625b and Kepler-1708b have remained elusive. If, however, these moons orbit along their respective ecliptic planes, we’d see tell-tale dips in brightness as these moons pass into the planet’s shadow, then cast their shadows back on the host primary.

HaBex
HabEx and its free-flying star shield. Credit: NASA/JPL

Eclipses, Transits and Occultations

In astronomy, we call this eclipse-transit pattern a series of mutual events, as one body passes in front of another. In our own solar system, Jupiter is a prime example of this. Earth and the Moon experience similar sorts of events twice a year during what are known of as eclipse seasons.

Transits
Types of transiting ‘exo-eclipse’ events. Credit: University of Michigan.

“HWO’s primary mission is to search for signatures of life on planets orbiting other stars. To achieve this, HWO will need to observe many nearby star systems, sometimes for several days at a time,” says Limbach. “’During these observations, HWO will measure the reflected light from the directly imaged planets in the system. If an exo-eclipse (or transit) occurs during this time, we would observe significantly less light from the planet during the eclipse (up to about 30% less for an Earth-Moon analog, depending on the orbital phase).”

We already have some idea an ‘exo-eclipse’ or transit event might look like from a distance. In 2008, NASA repurposed the Deep Impact spacecraft for what was known of as the EPOXI (a combination of two acronyms: the Deep Impact Extended Investigation and the Extrasolar Planet Observation and Characterization missions). Looking back at the Earth-Moon system, EPOXI saw a series of transits. These give researchers some idea just what such an event might look like.

EPOXI
EPOXI sees the Moon transit the Earth. NASA/EPOXI

Looking for Earth Analogs

The Habitable Worlds Observatory would work in the near-infrared, a band where large moons may outshine their host worlds. With an Earth-Moon analog system, HWO is expected to see 2-20 mutual events out to 10 parsecs distance. Larger gas giant events might be detectable out to 20 parsecs away.

“Since multiple exomoon detection methods will be available to HWO and we predict that these will facilitate exomoon detection, HWO may be capable of revealing general information about exomoons as a population, such as how common or rare large moons around Earth-like planets are, or the physical circumstances under which exomoons are readily found,” says Jacob Lustig-Yager (University of Washington). “If HWO is able to detect many exomoons, then this may open the door to such population studies in the future.”

To be sure, detection of exomoons via the exo-eclipses they produce will be difficult. This will represent the very cutting edge of what even the Habitable Worlds Observatory is capable of. This method will also have to contend with false signals. These include possible ‘exo-rings’ and even weather variability and rotation changing the albedo or overall brightness of the host primary. On the plus side, researchers note that younger systems should produce more mutual events. Think of the Earth-Moon system early in its history when the Moon was first ripped from the Earth and was much closer. This primordial Moon would’ve loomed large in the sky, producing lots of eclipses.

A Population of Exo-Moons

“The next aspect we are investigating is the spectroscopic detectability of ‘Earth-like’ moons orbiting gas giant planets in the habitable zone,” says Limbach. “While such moons have often been imaged in popular culture (e.g. Endor and Pandora), HWO may be the first observatory capable of detecting and characterizing them, should they exist.”

Lucy
Another eclipse seen from a distance. The May 15-16 2022 total lunar eclipse, as seen from 100 million kilometers distant courtesy of NASA’s Lucy spacecraft. Credit: NASA

Ultimately, the methods described could lead to detection of an entire population of exomoons, allowing us to say with some authority just how common they are in the cosmos.

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New Shepard’s 25th Launch Carries Six to the Edge of Space and Back

May 20th, 2024

Sending tourists to space is still relatively novel in the grand scheme of humanity’s journey to the stars. Dennis Tito took the first-ever paid trip in 2001, but since then, plenty of others have journeyed to the heavens. Increasingly, they’ve done so via systems developed by private companies. On Sunday, May 19th, Blue Origin, originally founded by Jeff Bezos to pursue his dreams of humanity’s future in space, successfully launched its seventh crewed mission – this time containing six first-time astronauts, including one that waited a long time for his day in space.

The astronauts’ professions and ages varied widely—from a twenty-something male venture capitalist to a retired female CPA, they came from different walks of life and various stages of life. One owns a brewery in France, while another is a trained stunt pilot. Most impressively, this was the opportunity for Ed Dwight to go into space.

He’s a former Air Force Captain who was the first black person ever to be selected for the Aerospace Research Pilot School, which he reached after being a test pilot in the Air Force for eight years. After making it through the first cut, Captain Dwight wasn’t selected to join NASA’s astronaut program, and many modern-day observers think that was simply down to the racism prevalent in the country back then.

Blue Origin promotional video for the NS-25 mission.
Credit – Blue Origin YouTube Channel

After leaving the military, he went on to have a successful life as an entrepreneur and became a well-regarded sculptor. Many of his themes focused on black culture, and he has over 100 pieces on show. He was also eventually made an honorary member of the US Space Force back in 2020.

Most importantly, he had never made it to space until now. Did we mention he’s also 90 years old and now, officially, the oldest person to have ever been sent to space? He and his fellow travelers—Mason Angel, Sylvain Chiron, Carol Schaller, Kenneth Hess, and Thotakura Gopichand—spent 10 minutes in space. If you’re interested in watching the process, there’s a YouTube video that tracks the whole mission—the launch takes place near 1:22 into the video.

Blue Origin video tracking the successful NS-25 mission – the company’s seventh crewed flight.
Credit – Blue Origin YouTube Channel

Congratulations to Blue Origin and the Shepard rocket team on another successful mission. This surely won’t be their last.

Learn More:
Blue Origin – Blue Origin Completes 25th Mission to Space with Six Crew Onboard
UT – Blue Origin’s New Shepard Completes 24th Flight; New Glenn Hopefully on the Horizon
UT – Finally! Blue Origin’s New Glenn Goes Vertical on the Launch Pad
UT – Blue Origin Reveals its Orbital Maneuvering Vehicle: Blue Ring

Lead Image:
A New Shepard launching.
Credit – Blue Origin

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That Recent Solar Storm Was Detected Almost Three Kilometers Under the Ocean

May 20th, 2024

On May 10th, 2024, people across North America were treated to a rare celestial event: an aurora visible from the Eastern Seabord to the Southern United States. This particular sighting of the Northern Lights (aka. Aurora Borealis) coincided with the most extreme geomagnetic storm since 2003 and the 27th strongest solar flare ever recorded. This led to the dazzling display that was visible to residents all across North America but was also detected by some of Ocean Networks Canada‘s (ONC) undersea sensors at depths of almost three kilometers.

ONC, an initiative of the University of Victoria supported by the Government of Canada, is one of the country’s major research facilities. Its network includes cabled observatories along the Pacific, Atlantic, and Arctic coasts of Canada and the Southern Ocean. that supply continuous power and internet to scientific instruments, cameras, and over 12,000 ocean sensors. According to a statement released on May 15th, ONC instrument platforms on Canada’s west and east coasts recorded the temporary distortion of Earth’s magnetic field at depths up to 2.7 km (1.68 mi) under the ocean.

Ocean Networks Canada infrastructure map. ONC operates world-leading observatories in the deep ocean, coastal waters, and the land of the Pacific, Atlantic, and Arctic coasts of Canada and the Southern Ocean. Credit: UVic/ONC

The disturbances triggered the movement of compasses, which the ONC uses to orient its Acoustic Doppler Current Profilers (ADCP) instruments that measure ocean currents. The most significant magnetic shift was detected by the ONC NEPTUNE cabled observatory off the coast of Vancouver Island. A compass belonging to this observatory, at a depth of 25 meters (82 ft) at the Folger Passage site, shifted within a range of +30 to -30 degrees. These magnetic disturbances were discovered during data quality control checks, which the ONC routinely performs to ensure their sensors work.

ONC data specialist Alex Slonimer was completing a daily check on the Ocean 3.0 Data Portal in late March when he first noticed the anomaly. Last week’s much larger solar storm reinforced the observation. Slonimer noticed that the peaks in compass headings were closely correlated to the peaks in the visible activity in the aurora. “I looked into whether it was potentially an earthquake, but that didn’t make a lot of sense because the changes in the data were lasting for too long and concurrently at different locations,” said Slonimer in a UVic News release. “Then, I looked into whether it was a solar flare as the sun has been active recently.” 

Professor Justin Albert of UVic’s Department of Physics and Astronomy welcomes this news and sees great potential for subsea detection of solar storms:

“The next two years will be the peak of the 11-year solar cycle. After a decade of relative inactivity, aurora events like this past weekend are likely to become more frequent over the next couple of years, although solar variability makes precise prediction of such events impossible. ONC’s network might provide a very helpful additional window into the effects of solar activity on the Earth’s terrestrial magnetism.”

Further Reading: UVIC

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More Evidence for the Gravitational Wave Background of the Universe

May 18th, 2024

The gravitational wave background was first detected in 2016. It was announced following the release of the first data set from the European Pulsar Timing Array. A second set of data has just been released and, joined by the Indian Pulsar Timing Array, both studies confirm the existence of the background. The latest theory seems to suggest that we’re seeing the combined signal of supermassive black hole mergers. 

Gravitational waves are ripples in spacetime caused by violent processes in the Universe. They were predicted by Einstein back in 1916 as part of his General Theory of Relativity. It is thought the waves are generated by accelerating masses such as merging black holes, colliding neutron stars and the like. They are expected to be able to travel through space, largely unimpeded by anything in their way.  Their existence was first detected in September 2015 by the Laser Interferometer Gravitational-Wave Observatory, or LIGO. They are thought to have come from a gravitational merger between tow black holes 1.3 billion light years away. 

The Laser Interferometer Gravitational-Wave Observatory is made up of two detectors, this one in Livingston, La., and one near Hanford, Wash. The detectors use giant arms in the shape of an “L” to measure tiny ripples in the fabric of the universe. Credit: Caltech/MIT/LIGO Lab

The gravitational wave background is a random distribution of gravity waves that permeate the Universe and it is this that was detected in the European Pulsar Timing Array. The background is thought to occur from multiple, superimposed gravity waves generated from supermassive black hole binaries for example. The observation of the gravity wave background can give us a great opportunity to study the Universe at large much like the Cosmic Background Radiation. The achievement would not have been possible if it wasn’t for the European Pulsar Timing Array, the Indian PTA, the North American Nanohertz Observatory and the Parkes PTA. 

The full-sky image of the temperature fluctuations (shown as color differences) in the cosmic microwave background, made from nine years of WMAP observations. These are the seeds of galaxies, from a time when the universe was under 400,000 years old. Credit: NASA/WMAP

A pulsar timing array (PTA) consists of a network of galactic pulsars that are monitored and analysed to detect patterns in their pulse arrival times on Earth. Essentially, PTAs function as galaxy-sized detectors. While pulsar timing arrays have various applications, they are most well-known when employing an array of millisecond pulsars to detect and analyse the long-wavelength gravitational wave background.

The paper, authored by a team led by J.Antoniadis from the Institute of Astrophysics from Greece explore the implications of the common low frequency signal observed int he latest data released from the pulsar timing array systems. Assembling data from the four different datasets, the team look for a signal comprising only high quality data. 

The conclusion was unmistakable, yet more evidence for a gravity wave background. Over time, and with more Pulsar Timing Array projects, the low frequency gravity wave background will become increasingly distinctive. The mission now is to interpret the details of all these signals to maximise the opportunity to explore the Universe in this new way.

Source : The second data release from the European Pulsar Timing Array: IV. Implications for massive black holes, dark matter and the early Universe

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When Uranus and Neptune Migrated, Three Icy Objects Were Crashing Into Them Every Hour!

May 18th, 2024

The giant outer planets haven’t always been in their current position. Uranus and Neptune for example are thought to have wandered through the outer Solar System to their current orbital position. On the way, they accumulated icy, comet-like objects. A new piece of research suggests as many as three kilomerer-sized objects crashed into them every hour increasing their mass. Not only would it increase the mass but it would enrich their atmospheres.

Uranus and Neptune are the two outermost planets in our Solar System. They differ from Jupiter and Saturn and share a number of characteristics based upon their composition. Atmospheres rich in ammonia and methane ice and also volumes of water distinguish them from the the other gas giants. Both have a distinctive blue hue to them, due to their composition  but Uranus is unique for its extreme axial tilt of 98 degrees. Observed from afar, it seems to orbit the Sun on its side. Neptune has wind speeds in excess of almost 2,000 kilometres. 

Image of Uranus from Webb

Observe the Solar System today and it seems a largely calm place but the Nice model (named after the location of the Cote d’Azure Observatory in Nice, France where it was developed) suggests the giant planets migrated from an initial location into their present position, long after the protoplanetary disk had dissipated. The idea became popular when it became clear that very long periods of time were required for Uranus and Neptune to form in their current location. 

In observations taken on 7 September 2021, researchers found that Neptune’s dark spot, which recently was found to have reversed course from moving toward the equator, is still visible in this image, along with a darkened northern hemisphere. There is also a notable dark, elongated circle encompassing Neptune’s south pole. The blue colour of both Neptune and Uranus is a result of the absorption of red light by the planets’ methane-rich atmospheres.

The model proposes that all the gas giants; Jupiter through to Neptune began their lives between 5 and 20 astronomical units from the Sun (one astronomical unit is equivalent to the average distance between Sun and Earth.) By comparison, Neptune is now at 30 astronomical units from Sun but some sort of catastrophic, chaotic event caused the planets to migrate out to their current positions. 

The simulations run by the team from the University of California suggests that it’s even possible that Neptune started out closer to the Sun than Uranus. The higher mass of Neptune seems to suggest this may be the case. Running through the simulations, the team estimate the amount of accretion on the planetesimals as they migrated out. 

The team announce that the ice giants seem to undergo bombardment from icy materials at an astonishing rate. The simulations showed that the extreme bombardment could have lasted for up to a million years with accretion rates of up to 3 planetesimals with a 1km radius every hour! This rate however seems to vary whether it is Uranus or Neptune and whether they switch position. In the simulations where Uranus is furthest from the Sun, both accrete at the same position, at between 22 and 26 astronomical units. Where Uranus is nearer to the Sun Neptune seems to offer some sort of shield and accretes the majority of planetesimals. 

It seems for now, the exact rates of accretion are still yet to be determined but we do know that the Solar System is far from peaceful and stable. Over many millions of years, the landscape of the Solar System has changed. It is fair to say that it will change again as the Sun ages but thankfully we are a few billion years off this yet. 

Source : Extensive Pollution of Uranus and Neptune’s Atmospheres by Upsweep of Icy Material During the Nice Model Migration

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Astronomers Discover the Second-Lightest “Cotton Candy” Exoplanet to Date.

May 18th, 2024

The hunt for extrasolar planets has revealed some truly interesting candidates, not the least of which are planets known as “Hot Jupiters.” This refers to a particular class of gas giants comparable in size to Jupiter but which orbit very closely to their suns. Strangely, there are some gas giants out there that have very low densities, raising questions about their formation and evolution. This is certainly true of the Kepler 51 system, which contains no less than three “super puff” planets similar in size to Jupiter but is about one hundred times less dense.

These planets also go by the moniker “cotton candy” giants because their density is comparable to this staple confection. In a recent study, an international team of astronomers spotted another massive planet, WASP-193b, a fluffy gas giant orbiting a Sun-like star 1,232 light-years away. While this planet is roughly one and a half times the size of Jupiter, it is only about 14% as massive. This makes WASP-193b the second-lightest exoplanet observed to date. Studying this and other “cotton candy” exoplanets could provide valuable insight into how these mysterious giants form.

The research team consisted of astronomers from the Astrobiology Research Unit and the Space Sciences, Technologies, and Astrophysics Research (STAR) Institute at the Université de Liège, the Oukaimeden Observatory at Cadi Ayyad University, the Massachusetts Institute of Technology (MIT), the Instituto de Astrofísica de Andalucía (IAA-CSIC), the European Southern Observatory (ESO), the Center for Space and Habitability at the University of Bern, the Center for Computational Astrophysics, the Cavendish Laboratory, and the British aerospace company Space Forge. The paper that describes their findings recently appeared in the journal Nature Astronomy.

Artist’s impression of the Kepler 51 system. Credits: NASA/ESA/L. Hustak, J. Olmsted, D. Player and F. Summers (STScI)

The new planet was initially spotted by the Wide Angle Search for Planets (WASP), an international collaboration that operates two observatories (SuperWASP-North and WASP-South) and searches for exoplanets using the Transit Method (aka. Transit Photometry). Between 2006 and 2008, and again in 2011/2012, the WASP-South observatory detected periodic dips in WASP-193’s brightness. These dips were consistent with an exoplanet with an orbital period of 6.25 days and provided estimates of the planet’s size.

As Khalid Barkaoui, an MIT postdoctoral student and the study’s lead author, explained in an MIT News statement, “To find these giant objects with such a small density is really, really rare. There’s a class of planets called puffy Jupiters, and it’s been a mystery for 15 years now as to what they are. And this is an extreme case of that class… [WASP-193b] is so very light that it took four years to gather data and show that there is a mass signal, but it’s really, really tiny.”

To obtain estimates of the planet’s mass and density, astronomers relied on high-resolution spectra (aka. the Radial Velocity Method) from ground-based telescopes. Unfortunately, these attempts failed to yield accurate information because the planet was far too light to have any detectable effect on its star. In the end, Barkaoui and his team’s analysis allowed them to constrain its mass, which allowed them to estimate its density at about 0.059 grams per cubic centimeter. This is a far cry from Jupiter, which has a density of about 1.33 grams per cubic centimeter.

Said Francisco Pozuelos, a senior researcher at the Institute of Astrophysics of Andalucia and the co-lead author of the study:

“We don’t know where to put this planet in all the formation theories we have right now, because it’s an outlier of all of them. We cannot explain how this planet was formed, based on classical evolution models. Looking more closely at its atmosphere will allow us to obtain an evolutionary path of this planet. We were initially getting extremely low densities, which were very difficult to believe in the beginning. We repeated the process of all the data analysis several times to make sure this was the real density of the planet because this was super rare.”

Artist’s impression of the hot Jupiter exoplanet WASP-69b, which orbits its star so closely that its atmosphere is being blown into space. Credit: Adam Makarenko/W. M. Keck Observatory

The researchers suspect that WASP-193b is composed mostly of hydrogen and helium, like all gas giants, and that these form a hugely inflated atmosphere that extends tens of thousands of kilometers farther than Jupiter’s atmosphere. These findings cannot be explained by conventional theories of planet formation and evolution, which makes WASP-193b an ideal candidate for follow-up observations. In the near future, the team hopes to conduct follow-up studies using the James Webb Space Telescope (JWST) and a technique developed by MIT assistant professor Julien de Wit.

This technique allows astronomers to measure the temperature, composition, and pressure of an exoplanet’s atmosphere to various depths, which can be used to precisely determine the planet’s mass. “The bigger a planet’s atmosphere, the more light can go through,” de Wit says. “So it’s clear that this planet is one of the best targets we have for studying atmospheric effects. It will be a Rosetta Stone to try and resolve the mystery of puffy Jupiters.”

Further Reading: MIT, Nature Astronomy

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Did Earth’s Multicellular Life Depend on Plate Tectonics?

May 18th, 2024

How did complex life emerge and evolve on the Earth and what does this mean for finding life beyond Earth? This is what a recent study published in Nature hopes to address as a pair of researchers investigated how plate tectonics, oceans, and continents are responsible for the emergence and evolution of complex life across our planet and how this could address the Fermi Paradox while attempting to improve the Drake Equation regarding why we haven’t found life in the universe and the parameters for finding life, respectively. This study holds the potential to help researchers better understand the criterion for finding life beyond Earth, specifically pertaining to the geological processes exhibited on Earth.

Here, Universe Today discusses this study with Dr. Taras Gerya, who is a Professor of Earth Sciences at the Swiss Federal Institute of Technology (ETH-Zurich) and co-author of the study, regarding the motivation behind the study, significant results, follow-up studies, what this means for the Drake Equation, and the study’s implications for finding life beyond Earth. So, what was the motivation behind this study?

Dr. Gerya tells Universe Today, “It was motivated by the Fermi Paradox (“Where is everybody?”) pointing out that the Drake Equation typically predicts that there are from 1000 to 100,000,000 actively communicating civilizations in our galaxy, which is too optimistic of an estimate. We tried to figure out what may need to be corrected in this equation to make the prediction with the Drake Equation more realistic.”

For the study, the research duo compared two types of planetary tectonic processes: single lid (also called stagnant lid) and plate tectonics. Single lid refers to a planetary body that does not exhibit plate tectonics and cannot be broken into separate plates that exhibit movement by sliding towards each other (convergent), sliding past each other (transform), or slide away from each other (divergent). This lack of plate tectonic activity is often attributed to a planetary body’s lid being too strong and dense to be broken apart. In the end, the researchers estimated that 75 percent of planetary bodies that exhibit active convection within their interiors do not exhibit plate tectonics and possess single lid tectonics, with Earth being the only planet that exhibits plate tectonics. Therefore, they concluded that single lid tectonics “is likely to dominate the tectonic styles of active silicate bodies in our galaxy”, according to the study.

Additionally, the researchers investigated how planetary continents and oceans contribute to the evolution of intelligent life and technological civilizations. They noted the significance of life first evolving in oceans due to them being shielded from harmful space weather with single-celled life thriving in the oceans for the first few billion years of Earth’s history. However, the researchers also emphasize how dry land provides a myriad of benefits for the evolution of intelligent life, including adaptations to various terrains, such as eyes and new senses, which contributed to animals evolving for speed to hunt among other biological assets that enabled life to adapt to the various terrestrial environments across the planet.

In the end, the researchers concluded dry land helped contribute to the evolution of intelligent life across the planet, including abstract thinking, technology, and science. Therefore, what were the most significant results from this study, and what follow-up studies are currently in the works or being planned?

Dr. Gerya tells Universe Today, “That very special condition (>500 million years coexistence of continents, oceans, and plate tectonics) is needed on a planet with a primitive life in order to develop an intelligent technological communicative life. This condition is very rarely realized: only <0.003-0.2 % of planets with any life may satisfy this condition.”

Dr. Gerya continues, “We plan to study water evolution in the planetary interior in order to understand how stability of surface ocean volume (implying stability of coexistence of oceans and continents) can be maintained for billions of years (like on Earth). We also plan to investigate the survival time of technological civilizations based on societal collapse models. We also started a project on the oxygenation state evolution of planetary interior and atmosphere in order to understand how oxygen-rich atmospheres (essential in particular for developing technological civilizations) can be formed on planets with oceans, continents and plate tectonics. Progress in these three directions is essential but will greatly depend on the availability of research funding.”

As noted, this study was motivated and attempts to improve the Drake Equation, which proposes a multivariable equation that attempts to estimate the number of active, communicative civilizations (ACCs) that exist in the Milky Way Galaxy. It was proposed by in 1961 Dr. Frank Drake to postulate several notions that he encouraged the scientific community to consider when discussing both how and why we haven’t heard from ACCs and reads as follows:

N = R* x fp x ne x fl x fi x fc x L

N = the number of technological civilizations in the Milky Way Galaxy who can potentially communicate with other worlds

R* = the average star formation rate in the Milky Way Galaxy

fp = the fraction of those stars with planets

ne = the average number of planets potentially capable of supporting life per star with planets

fl = the fraction of planets capable of supporting and developing life at some point in its history

fi = the fraction of planets that develop life and evolves into intelligent life

fc = the fraction of civilizations who develop technology capable of sending detectable signals into space

L = the length of time that technological civilizations send signals into space

According to the study, the Drake Equation estimates the number of ACCs range widely, between 200 to 50,000,000. As part of the study, the researchers proposed adding two additional variables to the Drake Equation based on their findings that plate tectonics, oceans, and continents have played a vital role in the development and evolution of complex life on Earth, which are as follows:

foc = the fraction of habitable exoplanets that possess notable continents and oceans

fpt = the fraction of habitable exoplanets that possess notable continents and oceans that also exhibit plate tectonics that have been functioning for at least 500 million years

Using these two new variables, the study provided new estimates for fi (chances of planets that develop life and evolve into intelligent life). So, what is the importance of adding two new variables to the Drake Equation?

Dr. Gerya tells Universe Today, “This allowed us to re-define and estimate more correctly the key term of the Drake equation fi – probability of a planet with primitive life to develop an intelligent technological communicative life. Originally, fi was (incorrectly) estimated to be very high (100%). Our estimate is many orders of magnitude lower (<0.003-0.2 %), which likely explains why we are not contacted by other civilizations.”

Additionally, when inputting these two new variables into the entire Drake Equation, the study estimates a far smaller number of ACCs at < 0.006 to 100,000, which is in stark contrast to the original estimates of the Drake Equation of 200 to 50,000,000. Therefore, what implications could this study have on the search for life beyond Earth?

Dr. Gerya tells Universe Today, “It has three key consequences: (1) we should not hope much that we will be contacted (probability of this is very low, in part because the life time of technological civilizations can be shorter than previously expected), (2) we should use remote sensing to look for planets with oceans, continents and plate tectonics (COPT planets) in our galaxy based on their likely distinct (CO2-poor) atmospheres and surface reflectivity signatures (due to the presence of oceans and continents), (3) we should take care about our own planet and civilization, both are extremely rare and must be preserved.”

This study comes as the search for life beyond Earth continues to gain traction, with NASA having confirmed the existence of 5,630 exoplanets as of this writing, with almost 1,700 being classified as Super-Earths and 200 being classified as rocky exoplanets. Despite these incredible numbers, especially since exoplanets first started being discovered in the 1990s, humanity has yet to detect any type of signal from an extraterrestrial technological civilization, which this study referred to as ACCs.

Arguably the closest we have come to receiving a signal from outer space was the Wow! signal, which was a 72-second radio blast received by Ohio State University’s Big Ear radio telescope on August 15, 1977. However, this signal has yet to be received since, along with a complete lack of signals at all. With this study, perhaps scientists can use these two new variables added to the Drake Equation to help narrow the scope of finding intelligent life beyond Earth.

Dr. Gerya concludes by telling Universe Today, “This research is part of an emerging new science – Biogeodynamics, which we try to support and develop. Biogeodynamics aims to understand and quantify relations between the long-term evolution of planetary interiors, surface, atmosphere, and life.”

How will these two new variables added to the Drake Equation help scientists find life beyond Earth in the coming years and decades? Only time will tell, and this is why we science!

As always, keep doing science & keep looking up!

The post Did Earth’s Multicellular Life Depend on Plate Tectonics? appeared first on Universe Today.



Hubble Sees a Brand New Triple Star System

May 17th, 2024

In a world that seems to be switching focus from the Hubble Space Telescope to the James Webb Space Telescope, Hubble still reminds us it’s there. Another amazing image has been released that shows the triple star system HP Tau, HP Tau G2, and HP Tau G3.  The stars in this wonderful system are young, HP Tau for example is so young that it hasn’t started to fuse hydrogen yet and is only 10 million years old!

Hubble was launched in 1990 and since then, has revolutionised our understanding of the Universe. It orbits Earth at an altitude of  around 547 kilometres and from that position has provided us stunning views of objects across the cosmos. It is about the size of a classic British double decker bus and at its core, a 2.4m mirror. The mirror collects incoming light from distant objects before directing it to one of a number of instruments that record and analyse it. 

Hubble Space Telescope
NASA’s Hubble Space Telescope flies with Earth in the background after a 2002 servicing mission. Credit: NASA.

The image recently released shows a wonderful example of a reflection nebula 550 light years away in Taurus. These particular types of nebula are made up of interstellar dust that reflect light from nearby stars, unlike emission nebula which glow in their own right. They have a characteristic blue hue to them due to the reflective properties of the dust. Looking at the image you can easily imagine a hollowed out cavity in the nebula that has been carved by the young stars. 

The triple stars at the heart of the system, HP Tau, HP Tau G2 and HP Tau G3 are young hot stars. HP Tau is a type of variable star known as a T Tau star. They are a type of star that are less than 10 million years old and named after the first start of its type to be discovered in Taurus. Identification is usually achieved by studies of their optical variability and strong lines in their spectra from the chromosphere. Given their young age, they are generally found still being surrounded by the cloud of gas and dust they have formed out of.

The amount of light emitted by HP Tau varies with time however this particular type of star tends to have regular and sometimes random fluctuations. The jury is still out on the random variations but it may be the young nature of the stars leads to slightly chaotic processes as the stars begin to settle down. Perhaps material from an accretion disk still in the process of collapsing may dump material onto the star causing it to flare.

Take a good look at the image though and make sure to study the stunning patterns of the nebulosity. Remember the light that left this object has travelled for 550 years before entering the optics of the Hubble Space Telescope. When Hubble turned its attention to HP Tau it did so as part of an investigation into protoplanetary disks. These disks are seen in many young hot stars and are believed to be the progenitors to planetary systems around stars.

Source : Hubble Views the Dawn of a Sun-like Star 

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The Venerable Hubble Space Telescope Keeps Delivering

May 17th, 2024

The world was much different in 1990 when NASA astronauts removed the Hubble Space Telescope from Space Shuttle Discovery’s cargo bay and placed it into orbit. The Cold War was ending, there were only 5.3 billion humans, and the World Wide Web had just come online.

Now, the old Soviet Union is gone, replaced by a smaller but no less militaristic Russia. The human population has ballooned to 8.1 billion. The internet is a fixture in daily life. We also have a new, more powerful space telescope, the JWST.

But the Hubble keeps delivering, as this latest image shows.

The lenticular galaxy NGC 4753 is about 60 million light-years away. Lenticular galaxies are midway between elliptical and spiral galaxies. They have large-scale disks but only poorly defined spiral arms. NGC 4753 sees very little star formation because like other lenticulars, it’s used up most of its gas. The fact that they contain mostly older stars makes them similar to elliptical galaxies.

Among lenticulars, NGC 4753 is known for the dust lanes surrounding its nucleus. Astronomers think that spirals evolve into lenticulars in dense environments because they interact with other galaxies and with the intergalactic medium. However, NGC 4753 is in a low-density environment. Its environment and complex structure make it a target for astronomers to test their theories of galaxy formation and evolution.

This Hubble image is the sharpest ever taken of NGC 4753, revealing its intriguing complexity and highlighting the space telescope’s impressive resolving power.

Astronomers think that NGC 4753 is the result of a merger with a dwarf galaxy over one billion years ago. The dwarf galaxy was gas-rich, and NGC 4753's distinct dust rings probably accreted from the merger. NGC 4753's powerful gravity then shaped the gas into the complex shapes we see in this image. Image Credit: ESA/Hubble & NASA, L. Kelsey
Astronomers think that NGC 4753 is the result of a merger with a dwarf galaxy over one billion years ago. The dwarf galaxy was gas-rich, and NGC 4753’s distinct dust rings probably accreted from the merger. NGC 4753’s powerful gravity then shaped the gas into the complex shapes we see in this image. Image Credit: ESA/Hubble & NASA, L. Kelsey

NGC 4763’s unique structure results from a merger with a dwarf galaxy about 1.3 billion years ago. The video below from NOIRlab explains what happened.

NGC 4753 also hosts two known Type 1a supernovae, which are important because they help astronomers study the expansion of the Universe. They serve as standard candles, an important rung in the cosmic distance ladder.

Galaxies like NGC 4753 may not be rare, but the viewing angle plays a key role in identifying them. Our edge-on view of the galaxy makes its lenticular form clear. We could be seeing others like it from different angles that obscure its nature.

This is a model of NGC 4753, as seen from various viewing orientations. From left to right and top to bottom, the angle of the line of sight to the galaxy's equatorial plane ranges from 10° to 90° in steps of 10°. Although galaxies similar to NGC 4753 may not be rare, only certain viewing orientations allow for easy identification of a highly twisted disk. This infographic is a recreation of Figure 7 from a 1992 research paper.
This is a model of NGC 4753, as seen from various viewing orientations. From left to right and top to bottom, the angle of the line of sight to the galaxy’s equatorial plane ranges from 10° to 90° in steps of 10°. Although galaxies similar to NGC 4753 may not be rare, only certain viewing orientations allow for easy identification of a highly twisted disk. This infographic is a recreation of Figure 7 from a 1992 research paper.

If we were looking at NGC 4753 from the “top” down, its detailed dust lanes wouldn’t be obvious to us. But fortunately, we are.

And so is the Hubble.

The post The Venerable Hubble Space Telescope Keeps Delivering appeared first on Universe Today.



The BepiColombo Mission To Mercury is Losing Power

May 17th, 2024

BepiColombo is a joint ESA/JAXA mission to Mercury. It was launched in 2018 on a complex trajectory to the Solar System’s innermost planet. The ESA reports that the spacecraft’s thrusters have lost some power.

BepiColombo’s mission is to complete a comprehensive investigation of Mercury’s magnetosphere, magnetic field, and internal and external structure. But travelling around in the inner Solar System is complicated, and the BepiColombo spacecraft will use more energy getting to Mercury than it takes to get to Pluto. The spacecraft will perform nine planetary flybys before reaching its destination at the end of 2025. BepiColombo has already performed one gravity assist at Earth, two at Venus, and five at Mercury. It’ll perform one more at Mercury in January 2025.

The Mercury Transfer Module (MTM) is the part of the spacecraft that delivers a pair of orbiters to Mercury. On April 26th, as the spacecraft was about to execute its next maneuver, the MTM didn’t deliver enough electrical power to its thrusters. A team working on it restored the thrust back to 90% on May 7th. But the MTM still isn’t deliver enough electricity to get back to 100% thrust.

Despite the power problems, the spacecraft is on track to complete its final Mercury flyby. A team is working to maintain the current power level and to understand how the diminished thrust will affect future maneuvers. They’re also working on restoring full power to the thrusters. To facilitate this, the mission’s flight control team at the European Space Operations Centre in Darmstadt, Germany, has arranged additional ground station passes.

BepiColombo employs a solar-electric propulsion system. Two 15-meter-long solar cells gather energy and deliver it to four ion thrusters that use xenon propellant. The thrusters are mounted on gimbals, making them aimable.

This schematic shows the components of BepiColombo's solar-electric propulsion system minus the solar arrays. There are four T6 gridded ion thrusters mounted on gimbals, three tanks of xenon gas holding 1,400 kg of xenon gas, a high-pressure regulator, four flow control units and two power processing units. The system also includes several metres of high-voltage harness and piping required to connect this complex system together. Image Credit: ESA
This schematic shows the components of BepiColombo’s solar-electric propulsion system minus the solar arrays. There are four T6 gridded ion thrusters mounted on gimbals, three tanks of xenon gas holding 1,400 kg of xenon gas, a high-pressure regulator, four flow control units and two power processing units. The system also includes several metres of high-voltage harness and piping required to connect this complex system together. Image Credit: ESA

BepiColombo consists of three separate spacecraft. The Mercury Transfer Module is kind of like a tugboat delivering two separate orbiters to Mercury. One of the orbiters is the Mercury Planetary Orbiter and it carries 11 scientific instruments, including cameras, several spectrometers, a magnetometer, and others. The other one is the Mercury Magnetospheric Orbiter, largely built by JAXA. It carries five groups of instruments, including one group that will study the plasma and neutral particles from the planet, its magnetosphere, and the solar wind.

This simple schematic shows the three separate spacecraft that combine to make the BepiColombo mission. Image Credit: ESA

The ESA says that they’ll share more information as it becomes available.

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