4450 - MARS & VENUS - were they water worlds

 

-    4452  -   MARS &  VENUS -  were they water worlds?   -    Evidence of ancient lake sediments at the base of Mars' Jezero crater offer new hope for finding traces of life in samples collected by NASA's Perseverance rover.  Perseverance touched down on Feb. 18, 2021 inside the Red Planet's 28-mile-wide Jezero Crater, which is believed to have once hosted a large lake and river delta.

-

-                                                        Venus and Earth

-----------------------------  4450    -   MARS &  VENUS -  were they water worlds

-

-    The rover has been scouring the crater in search of signs of past life and collecting and caching dozens of samples along the way for a possible future return to Earth.   Using the rover's Radar Imager for Mars' Subsurface Experiment (RIMFAX) instrument revealed new clues about how sediment layers formed over time on the crater floor.

-

-    As Perseverance rover travels across the surface of Mars, the RIMFAX instrument sends radar waves downward at 4-inch intervals and measures pulses reflected from depths of about 65.6 feet below the surface to create a subsurface profile of the crater floor.

-

-    The RIMFAX data showed evidence of sediment deposited by water that once filled the crater. It's possible that microbial life could have lived in the crater at this time and, if such life existed on Mars, sediment samples from this area would contain signs of their remains.

-

-    Two distinct periods of deposition occurred, creating layers of sediments on the crater floor that appear regular and horizontal, much like strata layers seen on Earth. Fluctuations in the lake's water levels caused some of the sediment deposits to form an enormous delta, which Perseverance traversed between May and December 2022.

-

-    The radar measurements also show an uneven crater floor below the delta, which is likely due to erosion before sediments were first deposited. After, as the lake dried up over time, the sediment layers in the crater were eroded, forming the geologic features visible on the Martian surface today.

-

-   The changes we see preserved in the rock record are driven by large-scale changes in the Martian environment.

-

-    Why also want to learn why Venus died on the other side of the Earth closer to the Sun?  Venus is only slightly smaller than the Earth, and so has enjoyed billions of years of a warm heart. But for this planet, sometimes called Earth’s sister, that heat has betrayed it. That planet is now wrapped in suffocating layers of a poisonous atmosphere made of carbon dioxide and sulfuric acid.

-

-    The pressures on the surface reach almost 100 times the air pressure at Earth’s sea level. The average temperatures are over 700 degrees Fahrenheit, more than hot enough to melt lead, while the deepest valleys see records of over 900 degrees.

-

-    If Venus is indeed Earth’s sister, she’s a twisted one. Like Mars, we suspect that Venus also once hosted a thinner, balmier atmosphere and a surface replete with liquid water oceans.

-

-    The reasoning here is a little more tenuous than for Mars where we can literally see the evidence for water before our very eyes, but the thinking is that both Venus and Earth formed in a roughly similar fashion, in roughly the same orbits with roughly the same material. Thus we should have been born with roughly the same amount of water.

-

-   Like Earth, most of that water would have been chemically bound up in rock, buried deep in the mantle. But some of it may have leeched to the surface or been delivered by hosts of water-rich comets shortly after formation, building up a supply on the surface, once again stabilized by a thick atmosphere.

-

-    What doomed Venus was not any fault of its own, but our own treacherous Sun. As stars age they gradually brighten. Day by day it’s imperceptible, but over the course of millions of years it completely changes the character of a star. Billions of years ago our Sun’s habitable zone was shifted inwards compared to where it rests now, but with increased brightness comes increased heat, and  that habitable zone steadily creeps outwards over time.

-

-   Did Venus ever host life? I doubt we’ll ever know, given the excruciating temperatures on the surface that make exploration nearly impossible. But it’s likely that it had water and a rich atmosphere – the basic ingredients were there. But if life did gain a foothold it did not last long. As our Sun aged, Venus got warmer and warmer. On a warmer planet, more water exists as vapor in the atmosphere than as liquid on the surface.

-

-    At first the changes were small, with nothing more than a higher dew point to mark the inexorable path to destruction. But at some point in the past Venus reached a tipping point. With too much water vapor, the atmosphere of Venus became too good at trapping the heat radiating from the surface. That radiation could not penetrate the haze and make into space, but instead was ensnared within the atmosphere itself, heating it up.

-

-   Venus entered a feedback loop, dumping more heat into the atmosphere, which boiled the oceans into more vapor, which increased the temperatures, and so on. First the shallow lakes and streams were gone, then came the deeper oceans, until every scrap of water was blowing in the winds of the atmosphere.

-

-    With its proximity to the ever-brightening Sun, the water vapor did not last long. Solar radiation pummeled it, disassociating its chemical bonds and sending the oxygen and hydrogen flying away, joining a grim procession beyond our solar system.

-

-   If Venus had plate tectonics like the Earth, then this is where that process came to end. With no water to act a lubricant, the great slow grinding of the plates seized up, locking the crust in place. This constant churning acts as a natural sink for carbon: the carbon dioxide binds to rocks which get pulled deep into the mantle, preventing too much carbon from building up in the atmosphere.

-

-   But without the cleansing effect of plate tectonics, carbon dioxide levels rose to dangerous heights, its own ability to absorb radiation from the surface choking off any remaining hope for rescuing the planet. Eventually the atmosphere would pile upon itself until it reached its present swollen size.

-

-    As our Sun aged, Venus strangled itself.  Venus is not alone in sharing that fate, for the Sun has not yet reached its final days. It continues to brighten, bringing more warmth to the solar system day by day, its habitable zone steadily inching outwards with every passing year.

-

-    At some point, approximately 500 million years from now, Venus will not be alone, The Earth’s oceans will boil, our continents will halt their ancient motion, and we will finally be twins with our sister: dead, lifeless, and strangling on our own bloated atmosphere.

-

-    Hycean planets may be able to host life even though they’re outside what scientists consider the regular habitable zone. Their thick atmospheres can trap enough heat to keep the oceans warm even though they’re not close to their stars.

-

-   The word hycean is a portmanteau of ‘hydrogen’ and ‘ocean’ and it describes worlds with surface oceans and thick hydrogen-rich atmospheres. Scientists think that they may be common around red dwarfs and that they could be habitable, although any life that exists on a hycean world would be aquatic.

-

-    Because they contain so much water, scientists think they’re larger than comparable non-hycean planets. Their larger size makes them easier targets for atmospheric study by the JWST. Though hycean worlds are largely hypothetical now, the JWST is heralding a new era in planetary science and may be able to show that they do exist.

-

-   The telescope’s ability to characterize exoplanet atmospheres could be the key to confirming their existence. Using transmission spectroscopy, the space telescope can watch as starlight travels through their atmospheres, revealing the presence of certain important chemicals and even biosignatures.

-

-    The exoplanet “TOI-270 d” could be a hycean world.  The JWST has ushered in a new era in atmospheric characterizations of temperate low-mass exoplanets with recent detections of carbon-bearing molecules in the candidate Hycean world “K2-18 b”.

-

-     TOI-270 is an M-dwarf (red dwarf) star about 73 light-years away. Red dwarfs are known to sometimes flare violently, ruling out habitability on nearby planets. However, they describe TOI-270 as a quiet star. It hosts three sub-Neptune planets, and the pair of outermost planets, TOI-270 c and d, are both candidate hycean worlds. TOI-270 d is considered the strongest candidate.

-

-    TOI-270 d is about 4.2 Earth masses and measures about 2.1 Earth radii. It takes just over 11 Earth days to complete an orbit, a fact that aids atmospheric study. The Hubble Space Telescope looked at TOI-270 d recently, and its observations suggested a hydrogen-rich atmosphere with some evidence of H2O. Those results warranted further examination with the more powerful JWST.

-

-   Though scientists still haven’t proven that hycean worlds exist, they know something about their atmospheric chemistry. On an ocean world with a thick, hydrogen-rich atmosphere, scientists expect to find strong signatures of CH4 (methane) and CO2 and no evidence of NH3 (ammonia.) This is what the JWST found at K2-18b, though there is still uncertainty if that exoplanet is a hycean world.

-

-    Every planet is different, but each type should have things in common.  For Hycean worlds, the presence of an ocean below a thin H2-rich atmosphere may be inferred by an enhancement of CO2, H2O, and/or CH4, together with a depletion of NH3.

-

-    Since TOI-270 d is a candidate hycean world, its spectroscopy should be similar to other hycean candidates like K2-18b.   Therefore, for the Hycean candidate TOI-270 d, observations of these key carbon-, nitrogen-, and oxygen- (CNO) bearing molecules are required to assess whether or not it is a Hycean world.

-

-   In October of 2023, the JWST observed TOI-270 b and d during two transits. The observations amounted to a total exposure time of 5.3 hours.  This rare event when the planets pass in front of their star allows for transmission spectroscopy of both planets.

-

-   Our atmospheric retrieval results support the inference of an H2-rich atmosphere on TOI-270 d and provide valuable insights into the abundances of dominant CNO molecules. Furthermore, the abundances are similar to what the JWST found on K2-18 b, another suspected hycean world.

-

-   But when it comes to water, the results are less certain.  We found only tentative evidence of H2O, with the detection significance and abundance estimates varying. The detection and abundance of H2O were more strongly dependent on what method the researchers used to analyze the data.

-

-    The appearance of CS2 (carbon disulphide) in TOI-270 d’s atmosphere is intriguing. It’s considered a detectable biomarker in hycean world atmospheres, as well as in hydrogen-rich atmospheres of rocky worlds, although the direct sources could also be volcanic or photochemical.

-

-    The atmospheric spectrum also contains hints of C2H6 (ethane.) Ethane can be a byproduct of photochemical reactions involving methane and other gases, including biogenic ones. Its presence is another indication that methane is present. The researchers also point out that the abundances of ethane and carbon disulphide are well above theoretical predictions.

-

-    All the researchers can conclude is that TOI-720 d is a candidate hycean world. But while the previous HST observations that hinted at its status showed the presence of H2O in an H2-rich atmosphere, the JWST observations provide more depth. The JWST’s more robust detections of CH4 and CO2, along with its non-detection of NH3, makes it an even stronger hycean world candidate.

-

-   The planet stands out as a promising Hycean candidate, consistent with its initial predictions as a world with the potential for habitable oceans beneath an H2-rich atmosphere.

-

-

May 2, 2024                MARS &  VENUS -  were they water worlds?                     4452

------------------------------------------------------------------------------------------                                                                                                                       

--------  Comments appreciated and Pass it on to whomever is interested. ---

---   Some reviews are at:  --------------     http://jdetrick.blogspot.com ----- 

--  email feedback, corrections, request for copies or Index of all reviews

---  to:  ------    jamesdetrick@comcast.net  ------  “Jim Detrick”  -----------

--------------------- ---  Friday, May 3, 2024  ---------------------------------

 

 

 

 

 

           

 

 

4451 - SUN - becomes a White Dwarf?

 -    4451 -  SUN   -  becomes a White Dwarf?  -   In a couple billion years, our Sun will be unrecognizable. It will swell up and become a  “red giant”, then shrink again and become a “white dwarf”. The inner planets aren’t expected to survive all the mayhem these transitions unleash, but what will happen to them? What will happen to the outer planets?

-------------------------------------  4451    -   SUN   -  becomes a White Dwarf?

-   Our Sun is about 4,600,000,000 years old. It’s firmly in the “main sequence” now, meaning it's fusing hydrogen into helium and releasing energy. But even though it’s about 330,000 times more massive than the Earth, and nearly all of that mass is hydrogen fuel, it will eventually run out.

-

-   In another five billion years or so, its vast reservoir of hydrogen will suffer depletion. As it burns through its hydrogen, the Sun will lose mass. As it loses mass, its gravity weakens and can no longer counteract the outward force driven by fusion. A star is a balancing act between the outward expansion of fusion and the inward force of gravity. Eventually, the Sun’s billions-of-years-long balancing act will totter.

-

-    With weakened gravity, the Sun will begin to expand and become a “red giant”.  The Sun will almost certainly consume Mercury and Venus when it becomes a red giant. It will expand and become about 256 times larger than it is now.

-

-    The inner two planets are too close, and there’s no way they can escape the swelling star. Earth’s fate is less certain. It may be swallowed by the giant Sun, or it may not. But even if it isn’t consumed, it will lose its oceans and atmosphere and become uninhabitable.

-

-   The Sun will be a red giant for about one billion years. After that, it will undergo a series of more rapid changes, shrinking and expanding again. But the mayhem doesn’t end there.  The Sun will pulse and shed its outer layers before being reduced to a tiny remnant of what it once was: a “white dwarf”.

-

-   This will happen to the Sun and almost all stars that host planets. Even the long-lived red dwarfs (M-dwarfs) will eventually become white dwarfs, though their path is different.

-

-    Astronomers know the fate of planets too close to the stars undergoing these tumultuous changes. But what happens to planets further away? To their moons? To asteroids and comets?

-

-   Practically all known planet hosts will evolve eventually into white dwarfs, and large parts of the various components of their planetary systems—planets, moons, asteroids, and comets—will survive.

-

-   There’s lots of observational evidence for this. Astronomers have detected planetary debris polluting the photospheres of white dwarfs, and they’ve also found compact debris disks around white dwarfs. Those findings show that not everything survives the main sequence to red giant to white dwarf transition.

-

-    Previous research had shown that when asteroids, moons and planets get close to white dwarfs, the huge gravity of these stars rips these small planetary bodies into smaller and smaller pieces.   The authors observed three white dwarfs over the span of 17 years. They analyzed the changes in brightness that occurred. Each of the three stars behaved differently.

-

-   When planets orbit stars, their transits are orderly and predictable. Not so with debris. The fact that the three white dwarfs showed such disorderly transits means they’re being orbited by debris. It also means the nature of that debris is changing.

-

-   The unpredictable nature of these transits can drive astronomers crazy—one minute they are there, the next they are gone.   As small bodies like asteroids and moons are torn into small pieces, they collide with one another until nothing’s left but dust. The dust forms clouds and disks that orbit and rotate around the white dwarfs.

-

-    The simple fact that we can detect the debris of asteroids, maybe moons or even planets whizzing around a white dwarf every couple of hours is quite mind-blowing.   These systems can evolve rapidly, in a matter of a few years.   The fate of these systems is far more complex than we could have ever imagined.

-

-    During the 17 years of observations, all three white dwarfs showed variability.  The first white dwarf (ZTF J0328?1219) was steady and stable until a major catastrophic event around 2011.  The system underwent a large collision event around 2011, resulting in the production of large amounts of dust occulting the white dwarf, which has since then gradually dispersed, though leaving sufficient material to account for the ongoing transit activity, which implies continued dust production.

-

-    The second white dwarf (ZTF J0923+4236) dimmed irregularly every couple of months and displayed chaotic variability on the timescale of minutes.  These long-term changes may be the result of the ongoing disruption of a planetesimal or the collision between multiple fragments, both leading to a temporarily increased dust production.

-

-   The third star (WD 1145+017) showed large variations in numbers, shapes and depths of transits in 2015. This activity concurs with a large increase in transit activity, followed by a subsequent gradual re-brightening, adding that the overall trends seen in the brightness of WD1145+017 are linked to varying amounts of transit activity.

-

-   But now all those transits are gone.   But astronomers have also found planetesimals, planets, and giant planets around white dwarfs, indicating that the stars’ transitions from main sequence to red giant don’t destroy everything. The dust and debris that astronomers see around these white dwarfs might come from asteroids or from moons pulled free from their giant planets.

-

-    For the rest of the Solar System, some of the asteroids located between Mars and Jupiter, and maybe some of the moons of Jupiter may get dislodged and travel close enough to the eventual white dwarf to undergo the shredding process.

-

-   When our Sun finally becomes a white dwarf, it will likely have debris around it. But the debris won’t be from Earth. One way or another, the Sun will destroy Earth during its red giant phase.  Whether or not the Earth can just move out fast enough before the Sun can catch up and burn it is not clear, but if it does the Earth would still lose its atmosphere and ocean and not be a very nice place to live.

-

-

April 29, 2023              SUN   -  becomes a White Dwarf?                               4451

------------------------------------------------------------------------------------------                                                                                                                       

--------  Comments appreciated and Pass it on to whomever is interested. ---

---   Some reviews are at:  --------------     http://jdetrick.blogspot.com ----- 

--  email feedback, corrections, request for copies or Index of all reviews

---  to:  ------    jamesdetrick@comcast.net  ------  “Jim Detrick”  -----------

--------------------- ---  Friday, May 3, 2024  ---------------------------------

 

 

 

 

 

           

 

 

 

 

 

 

           

 

 

4400 - Index of Reviews 4400 to 4450

 

  

            -  4400  -   Index of Reviews 4400  to 4450

            -     This index is of the 50 reviews from 4400 to 4450.  Indices of all previous reviews is available upon request.      Writing style is stocatto with each paragraph an idea and limited to a few pages in total.  Comments are always welcome.  See  https://jimdetrick@blogspot.net

             ----------------------------------------------------------------------------

            

            ----------------------------------  4400  -   Index of Reviews 4400  to 4450

           

       

            -     4400 - BLACKHOLES  -  stretch the mind?  -   Is there anything stranger in the universe than black holes? These bizarre, gravitational monstrosities don't only warp space and time; just thinking about them stretches and bends people's imaginations .

            -

            -     4401  - EMERGENT  GRAVITY  -  instead of dark matter?  -    In 2009, theoretical physicists proposed a radical reformulation of gravity. In this theory, gravity is not a fundamental force but rather a manifestation of deeper hidden processes. But in the 15 years since then, there hasn't been much experimental support for the idea. So where do we go next?

            -

            -      4402  - DARK  MATTER  TESTS  -     Most, if not all galaxies are surrounded by halos of this mysterious, unknown, but ubiquitous material.  This stuff also played a role in galaxy formation. The nature of that role is something astronomers are still figuring out. Today, they’re searching the infant Universe, looking for the tiniest, brightest galaxies. That’s because they could help tell the tale of dark matter’s role in galactic creation.

            -

            -    4403  -  BRIGHTEST  QUASAR -    The brightest quasar ever seen is powered by black hole that eats a 'sun a day'.   This quasar, as bright as 500 trillion suns, has evaded astronomers for over 40 years because of its incredible luminosity. Not only is it the brightest quasar ever seen, but it's also the brightest astronomical object in general ever seen. It's also powered by the hungriest and fastest-growing black hole ever seen.   It consumes the equivalent of over one sun's mass a day.

            -

            -     4404  -   PLANETS  -  why is solar system flat?  -    Have all 8 planets in our solar system ever aligned?    All eight planets will never truly be in a straight line, but they can get close to it.  The Sun, followed by Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune & Pluto.

            -

            -     4405  -  PLANETS  -  how do atmospheres vary?   -   What can they teach us about finding life beyond Earth?   Why study impact craters, planetary surfaces, exoplanets, astrobiology, solar physics, and comets, and what these fantastic scientific fields can teach researchers and space fans regarding the search for life beyond Earth?

            -

            -      4406  -  UNIVERSE  -  expanding at different rates?  -   James Webb telescope confirms there is something seriously wrong with our understanding of the universe.  Depending on where we look, the universe is expanding at different rates. Now, scientists using space telescopes have confirmed that the observation is not down to a measurement error.

            -

            -     4407  -   MOON   -  how old is the moon?   -    Moon is 40 million years older than we thought, tiny crystals from Apollo mission confirm.  A new analysis of zircon crystals from the Apollo 17 mission has revealed that the moon formed around 40 million years earlier than past geological evidence suggested. However, our cosmic companion may be even older than that.

            -

                  4408  -    SUN  -   eruption on March 24, 2024.  -  The sun erupted over the weekend,  flinging electromagnetic radiation towards Earth, even illuminating skies with spectacular aurora borealis. For the first time, ESA's satellites, unlikely space weather duo of SMOS and Swarm, tracked the severe solar storm which warped Earth's magnetic field.

            -

            -   4409  -   LIFE  -  on Mars and the farthest galaxy?    -    NASA's Perseverance rover may already have found signs of life on Mars.  The discovery of an ancient lake bed beneath the Perseverance rover's location on Mars could mean the robotic scout has already scraped up microbial fossils. But we won't know for sure until we fetch the sample.

            -

            -     4410  -    CENTAURS  -   are small planetary bodies ?  -   These planetary bodies orbit between Jupiter and Neptune and have baffled astronomers for sharing characteristics with both asteroids and comets. Centaurs got their name after the mythical half-horse, half-human creatures called centaurs due to their dual characteristics.

            -

            -     4411  -    SPEED  OF  LIGHT  -  think about it, amazing!    Light travels fast but space has enormous distances.   Andromeda Galaxy is the farthest thing you can see with the naked eye. Check it out. It took  2.5 million years to reach your eyes.

            -

            -      4412  -   CLIMATE  CHANGE  -    time, of course it is changing?  -    Climate change is messing with how we measure time.  It may have delayed the need for the world's timekeepers to add a "negative leap second" to standard time.   Struggle to wrap your head around daylight savings? Spare a thought for the world's timekeepers, who are trying to work out how climate change is affecting Earth's rotation, and in turn, how we keep track of time.

            -

            -    4413  -  NEUTRINO  FACTORY  -  making stardust particles? -    A stardust particle locked in meteorite holds secrets of a star's explosive death.  These particles are like celestial time capsules, providing a snapshot into the life of their parent star.

            -

            -     4414  -   NUCLEAR  ENERGY  -  solution waiting to happen?  -    In December 2022, after more than a decade of effort and frustration, scientists at the US National Ignition Facility (NIF) announced that they had set a world record by producing a fusion reaction that released more energy than it consumed, a phenomenon known as “ignition”.

            -

            -     4415  - SOLAR  ECLIPSE  -    in 2024, what we hope to learn? -  A total solar eclipse will be seen across the United States in April 2024.  When a rare total solar eclipse sweeps across North America on April 8, scientists will be able to gather invaluable data on everything from the sun's atmosphere to strange animal behaviors and even possible effects on humans.

            -

            -      4416  -    SUPERNOVA  EXPLOSION  -  we live on what's left behind?  -   The threat posed by stellar cataclysms such as supernovae and related phenomena such as gamma-ray bursts are cataclysms are remote, but when they occur closer to home they can pose a threat to life on Earth.

            -

            -     4417    -   EXOPLANET  -   search for life.  -    With all the in-motion SETI research underway, just how prepared are we for a confirmed, door-ringing neighborhood watch revelation?  We should begin to think about how we convey this information, possible impacts to society, to religion, to politics, to technology, to governments.

            -

            -  4418  -  EXOPLANET  FOUND  -  will it host life?      Hycean Planet Found? “TOI-270 d”.  It may be able to host life even though being outside what scientists consider the regular habitable zone. Exoplanet's thick atmospheres can trap enough heat to keep the oceans warm even though they’re not close to their stars.

            -

            -      4419  -  SOLAR  ECLIPSE – 2024 , much more to learn?       Although Earth-based telescopes can provide images of the sun in a higher resolution, these telescopes can't study the extreme ultraviolet part of the solar light spectrum. Because these frequencies are filtered out by Earth's atmosphere, ground-based telescopes therefore don't see many of the key phenomena driving the sun's behavior.

            -

            -     4420  -  UNIVERSE  EXPANSION  RATE?  -   how fast is it,  really?  -   The notion of the absolute speed limit comes from special relativity, but who ever said that special relativity should apply to things on the other side of the universe? That's the domain of a more general theory. A theory called “general relativity”.

            -

            -    4421  -   DARK  ENERGY  SURVEY  -  to explain the universe?  -    By the time DESI has completed its five-year run, it will have mapped over three million quasars and 37 million galaxies. That massive trove of data should help scientists understand if dark energy is changing. Whatever the eventual answer, the question is vital to understanding the Universe.

            -

            -      4422  -   STARS  -   from birth to death?  -    Hubble Telescope witnesses a new star being born in a stunning cosmic light show.  The infant star FS Tau B is blasting out a powerful jet of matter that is slamming into sounding material.

            -

            -     4423  -   PARKER  SOLAR  PROBE?   -    Parker Solar Probe was blasted by Coronal Mass Ejections 28 times in 4 years.  PSP was launched on August 12, 2018, with the goal of becoming the first spacecraft to touch the Sun while teaching us more about our host star than any spacecraft or solar instrument in human history.

            -

            -     4424  -  SOLAR  ECLIPSE  SPEED  -   only the shadow knows ?  -    April's total solar eclipse will travel at speeds ranging from 10 million miles an hour, half the speed of the fastest supernova explosion ever detected, to as slow as 1,565 mph, about twice the speed of a supersonic aircraft.

            -

            -     4425  -  MARS  -  craters filled with water?  -    New research shows that the Gale Crater, the landing spot for NASA’s “MSL Curiosity”, held water for a longer time than scientists thought. Life needs water, and it needs stability. So, if Gale Crater held water for a long time, it strengthens the idea that Mars could’ve supported life.

            -

            -     4426  -  MILKY  WAY  GALAXY  -  from birth to today.   As galaxies merge and collide, their hydrogen gas clouds are disrupted, which can create a frenzy of star birth.   Over time, the Milky Way’s long filaments of gas and dust coalesced and resulted in the modern spiral structure of the galaxy today.

            -

            -     4427  -  MILKYWAY GALAXY   -  how big is it?   -    Exactly how massive is the Milky Way? How do you weigh a galaxy? It's an astronomical challenge, particularly if it's the galaxy you call home. It turns out there are several ways to get a handle on the mass of the Milky Way.

            -

            -     4428  -  GAMMA  RAY  BURSTS  -  from stars that collide?  -  Two neutron stars begin to merge blasting jets of high-speed particles creating short gamma-ray bursts. These are the most powerful events in the known universe.  Gamma-ray bursts are short-lived outbursts of the highest-energy light. They can erupt with a quintillion (a 10 followed by 18 zeros) times the luminosity of our sun.   They are now thought to announce the births of new black holes, they were discovered by accident.

            -

            -     4429  -  FAST  RADIO  BURSTS  -     Fast radio-wave explosion ever found could be used to weigh the universe.    Astronomers traced a mysterious radio source to three merging galaxies 8 billion light-years away. Studying it could help uncover the universe's missing matter.

            -

            -     4430  - AGES  OF  STARS  -  how to measure it? -   The upcoming Roman Space Telescope will gather data from hundreds of millions of stars through its “Galactic Bulge Time Domain Survey”, one of three core community surveys it will conduct. Roman will look toward our galaxy's center a region crowded with stars—to measure how many of these stars change in brightness over time. These measurements will enable multiple science investigations, from searching for distant exoplanets to determining the stars' rotation rates.

            -

            -     4431  -  BLACK  HOLES  CAME  FIRST?  -       Black holes not only existed at the dawn of time, they birthed new stars and supercharged galaxy formation.    New theories are challenging classical understanding that they formed after the first stars and galaxies emerged.

            -

            -     4432  -    MOON  HISTORY  -  splashed off the Earth?  -   Scientists recently solved a long-standing mystery surrounding the moon's 'lopsided' geology. About 4.5 billion years ago, a small planet smashed into the young Earth, flinging molten rock into space. Slowly, the debris coalesced, cooled and solidified, forming our moon.

            -

            -     4433  -  AGE  OF  THE  UNIVERSE?  -  was it the beginning?      If we count from the start of the hot Big Bang, we learn that the Universe is 13.8 billion years old, with only a very tiny (1%) degree of uncertainty. But what gives us the right to call the start of the hot Big Bang "the beginning," particularly if we now can confidently state that a period of cosmic inflation preceded it?

            -

            -     4434  -  CALIFORNIA  EARTHQUAKE? -  did you feel the ground shake?  -    Fears grow over supervolcano that 'may swallow this entire US state' in apocalyptic eruption.  2 hours ago, Monday, April 15, 2024, fears are mounting over the potential eruption of a supervolcano in California, which has been dormant for hundreds of thousands of years.

            -

            -     4435  -  SUN'S  CORONA  PROBE  -  to touch the Sun?  -    NASA’s Parker Solar Probe (PSP) was launched on August 12, 2018, with the goal of becoming the first spacecraft to touch the Sun while teaching us more about our host star than any spacecraft or solar instrument in human history.

            -

            -     4436  -    MARS  ROBOTS  -  what have they found?  -    Perseverance is a rover on Mars.  It finds its “dream rock” to be a specific type of rock so important that it holds convincing clues to Mars’ ancient habitability.   If scientists could design the perfect rock for Perseverance to find, it would be one that displayed evidence of ancient water and was the type that preserves ancient organic material.

            -

            -    4437  -  METEORITES  -  teach us about our solar system? -   Meteorites provide our best information about how the solar system formed and evolved. This includes planet formation. We also obtain information on astrophysics (stellar processes) through studies of pre-solar grains.

            -

            -    4438  -    ATOMS  -  are mostly empty space?      Practically all of the matter we see and interact with is made of atoms, which are mostly empty space. Then why is reality so... solid?   Although, at a fundamental level, the Universe is made up of point-like quantum particles, they assemble together to create objects of finite sizes and masses, occupying specific amounts of volume, that is space..

            -

            -     4439  -  OCEAN  TEMPERATURES  -  control the weather?   -    El Niño to flip to La Niña are the names of ocean cyrrents in what could be the hottest year on record.  A quick flip from El Niño to La Niña is coming soon, but what does that mean for the U.S.?  El Niño is likely to give way soon, ushering in a quick switch to its opposite atmospheric and ocean pattern, La Niña.

            -

            -     4440  -   ASTEROIDS  -  a close flyby?  -    The asteroid discovered Tuesday (April 9, 2024) made an extremely close, but harmless, pass by planet Earth on April 11.   Asteroid 2024 GJ2 is roughly the size of a car and, since its discovery, astronomers calculated that the space rock would graze by Earth at a mere 12-thousand-mile distance.     That's just three percent the distance between the Earth and the moon.

            -

            -     4441  - MARS  - Curiosity,  Ingenuity helicopter, Perseverance?      There was no intelligent life, but there may have been simple life in those lakes. Once we get Comet Geyser and the other samples back to Earth, we may find out for sure.

            -

            -    4442  -  NEUTRINOS  -      The Ghost Particle: What is a “Neutrino” and could it be the key to modern physics?   It came from deep space, moving at the speed of light, and crashed into Antarctica. Deep below the ice, it met its end. It wasn't an asteroid or alien spacecraft, but a particle that rarely interacts with matter, known as a “neutrino”. 

            -

            -      4443  -   DARK  MATTER  -  what is it , really?  -     Dark matter is the mysterious stuff that fills the universe but no one has ever seen.  “Dark matter” makes up over 80% of all matter in the universe, but scientists have never seen it.   We only assume it exists because, without it, the behavior of stars, planets and galaxies simply wouldn't make sense.

            -

            -     4444  -  “IO”  JUPITER'S  MOON  -  an active volcanic world?  -    Close flybys of Io, one of Jupiter’s moons and the most volcanically active world in our solar system, have revealed a lava lake and a towering feature called “Steeple Mountain” on the moon’s alien surface.

            -

            -      4445  -  UNIVERSE  EXPANDING   -  how to measure it?  -   James Webb Telescope continues to confirm that the Universe is behaving strangely?  Over a century ago, astronomers Edwin Hubble and Georges Lemaitre independently discovered that the Universe was expanding. Since then, scientists have attempted to measure the rate of expansion (known as the Hubble-Lemaitre Constant) to determine the origin, age, and ultimate fate of the Universe.

            -

            -      4446  -   OLDEST  GALAXY  -   and the oldest stars ? v  A new program to photograph one-quarter of the southern sky is using the “Blanco” 4 meter telescope in Chile and equipment designed to identify the most ancient fossil stars in the Milky Way and our galactic neighbor. By uncovering these relics, astronomers hope to paint a better picture of how stars have enriched the cosmos with the elements that make up all that we see around us.

            -

            -     4447  -  CLOSE  ENCOUNTERS  -  will we know it if we see it?      To spot potential intelligent life out there in the great beyond, first you must cast a net wide by using an array of techniques and technologies.   Any "fishing expedition" for Extra - Terrestrials includes close-in studies of life in extreme environments right here on Earth, to help us recognize any signatures we might find on Mars or deep diving through the icy shell of Jupiter's moon, Europa.

            -

            -    4448  -   EXOPLANETS  -  can we find them?  -   The Hubble Space Telescope joins the hunt for newborn exoplanets.   James Webb Space Telescope quickly spotted signs of a forming exoplanet, but,  not the one that astronomers had expected to see.

            -

            -     4449  -     COMET  DISCOVERIES  ?   The spacecraft 'SOHO' discovers its 5,000th comet.  In December 1995, an observatory traveled nearly a million miles from Earth as part of a $1 billion mission to study the sun.

            -

            -   4450  -  CONSTELLATION  CASSIOPEIA  -  stars after explosion?  -   When a massive star runs out of fuel, it collapses in on itself and then explodes. It leaves behind a dense core where the protons and electrons are crushed into neutrons. It’s called a “neutron star”, and they’re the smallest and densest stellar objects in the Universe other than black holes.

            -

            -

            March 24, 2024             Index of Reviews 4400 to 4450                          4450                                                                                              ---------------------------------------------------------------------------------------

            -----  Comments appreciated and Pass it on to whomever is interested. ---

            ---   Some reviews are at:  --------------     http://jdetrick.blogspot.com ----- 

            --  email feedback, corrections, request for copies or Index of all reviews

            ---  to:  ------    jamesdetrick@comcast.net  ------  “Jim Detrick”  -----------

            --------------------- ---  Monday, April 29, 2024  ---------------------------