Amazing Planetary Movements

[Witness1970]

A simple image of the way the moon moves if we look at the solar system from directly above.  As the moon orbits the Earth and the Earth orbits the sun, the moon's movements become more complicated.  The moon takes about 27.3 days to orbit the earth, and the moon phases repeat about every 29.5 days.  The difference is due to the fact that as the moon orbits the earth, the earth is also moving around the sun.  It is the relative positions of the sun, earth, and moon that creates the phases of the moon that we observe.

 

If we add in the movement of the sun around the center of the galaxy, it creates a completely new picture.  Once again, we are taking a certain perspective.  This image is a view from directly above the galactic center.  The orbit of the sun around the center of the galaxy is estimated to take somewhere between 225,000,000 and 250,000,000 years.  The image below is an approximation of what you would see from directly above the galactic center.

 

T

This is showing the movements of the moon around the earth, which is moving around the sun, which is moving around the galactic center.   None of these orbits are actually perfect circles but are actually more elliptical.  This, of course, is a simplified image.  The image shows the movements of the moon but only uses 16 circles.  An image showing between 225,000,000 and 250,000,000 would of course be ridiculously large.

 

Even more complicated would be trying to show the movement of the galaxy through space.  It would be a very complex image.  And these images are just from one viewpoint, above (or below) the galaxy, perpendicular to the plane of the galaxy.

[Witness1970]

From another viewpoint, we get a different perspective from the one above.

 

https://www.google.com/search?q=helical+solar+system&client=ms-android-tracfone-us-rvc3&sca_esv=ec1c0fa4563bd641&source=android-browser&sxsrf=AHTn8zoy1RyTs7d0AcxGkLhAicpU3EuRIg%3A1744979003320&ei=O0QCaOqRE8Tep84P2uipwQ0&ved=0ahUKEwiqm4ityeGMAxVE78kDHVp0KtgQ4dUDCBA&uact=5&oq=helical+solar+system&gs_lp=Egxnd3Mtd2l6LXNlcnAiFGhlbGljYWwgc29sYXIgc3lzdGVtMgsQABiABBiRAhiKBTIGEAAYFhgeMgsQABiABBiGAxiKBTILEAAYgAQYhgMYigUyCxAAGIAEGIYDGIoFMgUQABjvBUjuP1DCCFinH3ABeACQAQCYAYsBoAGqCaoBBDEwLjO4AQPIAQD4AQGYAg2gAoIJwgIOEAAYgAQYsAMYhgMYigXCAggQABiwAxjvBcICCxAAGIAEGLADGKIEwgILEC4YgAQY0QMYxwHCAgUQABiABMICCxAuGIAEGMcBGK8BwgIaEC4YgAQY0QMYxwEYlwUY3AQY3gQY4ATYAQHCAggQABgWGAoYHsICCBAAGIAEGKIEmAMAiAYBkAYEugYGCAEQARgUkgcEMTAuM6AHi2CyBwM5LjO4B_wI&sclient=gws-wiz-serp#fpstate=ive&vld=cid:6a20f387,vid:0jHsq36_NTU,st:0

 

Is this model perfect?  NO!  In the video, he states that the heliocentric model of the solar system is wrong.  It isn't wrong, it is merely from a different perspective, a different viewpoint.  The heliocentric model of the universe works just fine from one perspective and the model shown above is fine from another perspective, and this video just shows the movement from a third perspective. 

 

The video is very nice but has its own flaws.  As the sun moves around the center of the galaxy, there is something of a wobble so that the sun is sometimes slightly above the galactic plane and is sometimes slightly below the galactic plane.  The video does show how the sun moves through space as it orbits the galactic center.  

Edited April 18, 2025 by Witness1970
corrected some spelling errors.

[Witness1970]

Is time real?  This might sound like it is off topic, but is it really?

 

There have been science fiction programs about travelling through time.  But what is time really?

 

We measure time with movements of the heavenly bodies.  When the earth makes one rotation, it is called a day.  It actually takes 23 hours and 56 minutes for the earth to rotate one time, but since the earth is also moving around the sun, it affects what we observe to be a day.  When the earth makes a complete orbit around the sun, it is called a year.  It takes 365.2422 days for the earth to make one full orbit.  This means we need to use 97 leap years out of every 400 years to keep the seasons close to the same time of year.

 

Since our measurement of time is based on the movements of physical objects, time is really just another space dimension.  So, this post is still about planetary movements, since time is just a measure of the relative positions of objects as they move.

 

When we make appointments, it is said to use 4 dimensions.  A street address (which can be located using latitude and longitude) on the 4th floor meeting room, a measure of height (a 3rd dimension) and the time is 9:00 AM (a 4th dimension).  But when we say 9:00 AM, we are really describing time in terms of the position of the sun relative to our position.  This means that the time mentioned is just another description of the position of heavenly bodies relative to our position.  

 

No! We can never travel back through time.  The past does not exist except as a memory.

[Witness1970]

Gravity travels at the speed of light.  If the black hole at the center of the galaxy suddenly disappeared objects would begin to drift away.  Anything within one (1) light-year would start to drift away after one year.  The solar system, which is approximately 25,000 light-years from galactic center would start to drift away after 25,000 years. The edge of the galaxy, which is approximately 50,000 light-years from galactic center would start to drift away after 50,000 years.

 

If you could observe this from a position 100,000 light-years from the center of the galaxy, everything would appear to start drifting away at exactly the same time.  The object that is 1 light-year from the center would start drifting away after one year but the light from that object would take another 99,999 years to reach us.  The solar system would start drifting away after 25,000 years and the light from the solar system would reach us after another 75,000 years. The objects at the edge of the galaxy would start drifting away after 50,000 and the light from those objects would take another 50,000 years to reach us.  Simply put we would see all these things 100,000 years after the black hole disappeared.  I am of course talking about the objects that are on the side of the galaxy nearest to us.  Other objects would take completely different calculations.

 

If the gravity from the center of the galaxy somehow diminished 30,000 years ago, our solar system would be reacting to the gravity that existed 25,000 years ago.  The edge of the galaxy would still be reacting to the gravity that existed 50,000 years ago since the gravity change has not reached out that far yet.

 

Mind-blowing thoughts!

Edited April 18, 2025 by Witness1970

[Witness1970]

https://www.sciencealert.com/black-holes-burp-years-after-shredding-stars-and-we-dont-know-why

 

Black holes burp almost 3 years after eating a star!

[just1-4all]

Pretty cool! Pretty awe-inspiring the scale and power of Jehovah's works.

[Witness1970]

Raining diamonds on Uranus and Neptune:

 

It's raining diamonds

The idea of diamond rain was first proposed before the Voyager 2 mission which launched in 1977. The reasoning was pretty simple: We know what Uranus and Neptune are made of, and we know that stuff gets hotter and denser the deeper into a planet you go. The mathematical modeling helps fill in the details, like that the innermost regions of the mantles of these planets likely have temperatures somewhere around 7,000 kelvins (12,140 degrees Fahrenheit, or 6,727 degrees Celsius) and pressures 6 million times that of Earth's atmosphere.

Those same models tell us that the outermost layers of the mantles are somewhat cooler — 2,000 K (3,140 F or 1,727 C — and somewhat less intensely pressurized (200,000 times Earth's atmospheric pressure). And so, it's natural to ask: What happens to water, ammonia and methane at those kinds of temperatures and pressures?

With methane, in particular, the intense pressures can break the molecule apart, releasing the carbon. The carbon then finds its brethren, forming long chains. The long chains then squeeze together to form crystalline patterns like diamonds.

The dense diamond formations then drop through the layers of the mantle until it gets too hot, where they vaporize and float back up and repeat the cycle — hence the term "diamond rain."

 

EDIT: https://www.space.com/diamond-rain-atmosphere-uranus-neptune

Edited August 15, 2025 by Witness1970

[Witness1970]

Deep gashes in the earth are slicing up cities, swallowing houses and displacing vast numbers of people

 

https://www.nature.com/articles/d41586-025-02745-x

 

Not exactly earthquakes, but interesting.

 

Other sources  https://www.bing.com/search?pglt=299&q=Huge+Cracks+in+the+Earth+Are+Slicing+through+Cities%2C+Swallowing+Houses+and+Displacing+Thousands+of+People+Hundreds+of+thousands+of+people+are+at+risk+of+losing+homes%2C+businesses—and+lives—as+giant+“gullies”+expand+into+cities+across+Africa+By+Miryam+Naddaf+%26+Nature+magazine+An+aerial+view+over+an+urban+gully+in+Kamonia%2C+Democratic+Republic+of+Congo+on+March+20%2C+2025+A+view+of+a+deep+urban+gully+in+Kamonia+in+the+Democratic+Republic+of+the+Congo.+More+than+3%2C000+people+are+at+risk+of+this+gully+expanding.+Ruben+Nyanguila%2FAnadolu+via+Getty+Images+Natural+Disasters+Gigantic+trenches+known+as+gullies+are+opening+up+in+cities+in+Africa%2C+swallowing+up+homes+and+businesses%2C+sometimes+in+an+instant%2C+a+study+has+found.+About+118%2C600+people%2C+on+average%2C+in+the+Democratic+Republic+of+the+Congo+(DRC)+alone+were+displaced+between+2004+and+2023%2C+according+to+researchers+reporting+their+findings+in+Nature.&cvid=175297d6f1c549439235e8f1f60595f6&gs_lcrp=EgRlZGdlKgYIABBFGDkyBggAEEUYOTIHCAEQ6wcYQNIBCTExMjUyajBqMagCCLACAQ&FORM=ANNTA1&PC=ACTS

[Witness1970]

Most orbits are not circular.  They are elliptical. Circular orbits would be very rare.

 

The reason that most bodies in the universe would have elliptical orbits is because there are 2 forces that act on those objects.  The smaller body would continue in a straight line if not acted on by gravity from a larger body.

 

Using the sun and earth as examples.  The earth would continue moving in a straight line if not for the sun's gravity.  The earth is going fast enough to move away from the sun slightly.  Due to the law of conservation of angular momentum, as the earth moves away from the sun, it slows down.  Due to the earth slowing down, the gravity from the sun pulls it in closer and the earth speeds up again.  This causes the earth's orbit to be elliptical.

 

Will the earth's orbit ever be a perfect circle?  The earth has been in existence for an estimated 4.5 billion years.  The orbit is still elliptical.  Maybe someday several billion years in the future, the earth's orbit might be a perfect circle.  We can wait and see!

Edited October 13, 2025 by Witness1970

[Witness1970]

Time travels faster on Mars than on Earth, and here's why

 

https://www.space.com/astronomy/mars/time-travels-faster-on-mars-than-on-earth-and-heres-why

[Witness1970]

A bright galaxy called MoM-z14, found using NASA’s James Webb Space Telescope, is the farthest yet detected, existing just 280 million years after the big bang.

 

NASA Webb Pushes Boundaries of Observable Universe Closer to Big Bang - NASA Science

[Witness1970]

For its 100th birthday, the Schrödinger equation, which describes how the quantum world behaves, is getting a glow-up. Physicists now ask what happens when the observer is part of that quantum world.

 

The Schrödinger equation, formulated by Erwin Schrödinger in 1925, is a fundamental equation in quantum mechanics that describes how the quantum state of a physical system evolves over time. As the equation approaches its 100th birthday, physicists are exploring its implications when the observer is part of the quantum world, raising questions about the nature of reality and the observer's role in the quantum state. This ongoing research reflects the ongoing relevance and significance of the Schrödinger equation in understanding quantum phenomena and its potential applications in various fields.

 

https://www.news.uzh.ch/en/articles/news/2025/schroedingers-legacy.html

[Mike047]

I'm all for feeding Schrödinger's cat

[Barbllm]

Found this on another website. These are the patterns made by various planetary orbits:

 

[Witness1970]

On 1/31/2026 at 5:10 PM, Barbllm said:

Found this on another website. These are the patterns made by various planetary orbits:

 

I wonder about perspective of these views.  Where would the observer be?

[Witness1970]

Earth's precession is a slow, continuous wobble of its rotational axis, completing a full cycle approximately every 26,000 years.
What is Earth's Precession?
Earth's precession, also known as axial precession, is the gradual shift in the orientation of Earth's axis of rotation. This motion causes the axis to trace out a conical shape over time, with a tilt of about 23.4°, known as the obliquity of the ecliptic, similar to the wobble of a spinning top (axial precession). The full precessional cycle takes roughly 26,000 years, during which the positions of the equinoxes slowly move westward along the ecliptic relative to the fixed stars. 
Wikipedia
+1
Causes of Precession
The primary cause of Earth's precession is the gravitational torque exerted by the Sun and Moon on Earth's equatorial bulge. Because Earth is not a perfect sphere but slightly flattened at the poles, the gravitational pull on the bulge generates a torque perpendicular to the axis of rotation, causing the axis to slowly rotate in space. Planetary gravitational influences also contribute slightly, causing planetary precession, but this effect is much smaller than the dominant lunisolar precession. 
Wikipedia
+2
Historical Discovery
The phenomenon was first identified by the Greek astronomer Hipparchus around 130 BC. By comparing his observations with older records, he noticed that the positions of the equinoxes had shifted by about 2° over 169 years, leading him to describe this motion as the precession of the equinoxes. This discovery explained why the "first point of Aries," marking the spring equinox, gradually moves through different constellations over millennia. 
NASA
+1
Effects of Precession
Pole Star Shift: The star currently near the north celestial pole, Polaris, will not always occupy this position. In the distant future, stars like Vega will become the north star. 
1
Equinox Movement: The vernal equinox slowly shifts westward along the ecliptic at a rate of about 50.26 arc-seconds per year, affecting the alignment of calendars and celestial coordinates. 
1
Astronomical Implications: Precession introduces a difference between the tropical year (based on the Sun) and the sidereal year (based on stars), which is important for precise astronomical observations and long-term climate studies. 
1
Interaction with Other Cycles: Precession combines with other orbital variations, such as the 41,000-year tilt oscillation and 71,000-year orbital plane precession, influencing Earth's long-term climate patterns, including the Milankovitch cycles. 
1

2 Sources
Modern Understanding
Today, precession is described in terms of general precession, which combines the precession of the equator (dominant) and the precession of the ecliptic (minor). Advanced techniques like very long baseline interferometry (VLBI) allow precise measurement of Earth's orientation relative to distant celestial objects, improving our understanding of precession and its variations. 
Cambridge University Press & Assessment

In summary, Earth's precession is a slow, gyroscopic wobble caused by gravitational forces on its equatorial bulge, with profound effects on celestial navigation, the position of the pole star, and long-term astronomical and climatic cycles.

[Witness1970]

[Witness1970]

Milankovitch cycles

 

https://science.nasa.gov/science-research/earth-science/milankovitch-orbital-cycles-and-their-role-in-earths-climate/

 

https://science.nasa.gov/science-research/earth-science/why-milankovitch-orbital-cycles-cant-explain-earths-current-warming/

Milankovitch (Orbital) Cycles and Their Role in Earth’s Climate

NASA Science Editorial Team

Feb 27, 2020

Article

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• (The pictures didn't work in the post.  You can view the article with pictures on the link)
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Our lives literally revolve around cycles: series of events that are repeated regularly in the same order. There are hundreds of different types of cycles in our world and in the universe. Some are natural, such as the change of the seasons, annual animal migrations or the circadian rhythms that govern our sleep patterns. Others are human-produced, like growing and harvesting crops, musical rhythms or economic cycles.

Cycles also play key roles in Earth’s short-term weather and long-term climate. A century ago, Serbian scientist Milutin Milankovitch hypothesized the long-term, collective effects of changes in Earth’s position relative to the Sun are a strong driver of Earth’s long-term climate, and are responsible for triggering the beginning and end of glaciation periods (Ice Ages).

Specifically, he examined how variations in three types of Earth orbital movements affect how much solar radiation (known as insolation) reaches the top of Earth’s atmosphere as well as where the insolation reaches. These cyclical orbital movements, which became known as the Milankovitch cycles, cause variations of up to 25 percent in the amount of incoming insolation at Earth’s mid-latitudes (the areas of our planet located between about 30 and 60 degrees north and south of the equator).

The Milankovitch cycles include:

1. The shape of Earth’s orbit, known as eccentricity;
2. The angle Earth’s axis is tilted with respect to Earth’s orbital plane, known as obliquity; and
3. The direction Earth’s axis of rotation is pointed, known as precession.

 

 

Play Video

Credit: NASA/JPL-Caltech

Eccentricity – Earth’s annual pilgrimage around the Sun isn’t perfectly circular, but it’s pretty close. Over time, the pull of gravity from our solar system’s two largest gas giant planets, Jupiter and Saturn, causes the shape of Earth’s orbit to vary from nearly circular to slightly elliptical. Eccentricity measures how much the shape of Earth’s orbit departs from a perfect circle. These variations affect the distance between Earth and the Sun.

Eccentricity is the reason why our seasons are slightly different lengths, with summers in the Northern Hemisphere currently about 4.5 days longer than winters, and springs about three days longer than autumns. As eccentricity decreases, the length of our seasons gradually evens out.

The difference in the distance between Earth’s closest approach to the Sun (known as perihelion), which occurs on or about January 3 each year, and its farthest departure from the Sun (known as aphelion) on or about July 4, is currently about 5.1 million kilometers (about 3.2 million miles), a variation of 3.4 percent. That means each January, about 6.8 percent more incoming solar radiation reaches Earth than it does each July.

When Earth’s orbit is at its most elliptic, about 23 percent more incoming solar radiation reaches Earth at our planet’s closest approach to the Sun each year than does at its farthest departure from the Sun. Currently, Earth’s eccentricity is very slowly decreasing and is approaching its least elliptic (most circular), in a cycle that spans about 100,000 years.

The total change in global annual insolation due to the eccentricity cycle is very small. Because variations in Earth’s eccentricity are fairly small, they’re a relatively minor factor in annual seasonal climate variations.

 

Play Video

Credit: NASA/JPL-Caltech

Obliquity – The angle Earth’s axis of rotation is tilted as it travels around the Sun is known as obliquity. Obliquity is why Earth has seasons. Over the last million years, it has varied between 22.1 and 24.5 degrees with respect to Earth’s orbital plane. The greater Earth’s axial tilt angle, the more extreme our seasons are, as each hemisphere receives more solar radiation during its summer, when the hemisphere is tilted toward the Sun, and less during winter, when it is tilted away. Larger tilt angles favor periods of deglaciation (the melting and retreat of glaciers and ice sheets). These effects aren’t uniform globally -- higher latitudes receive a larger change in total solar radiation than areas closer to the equator.

Earth’s axis is currently tilted 23.4 degrees, or about half way between its extremes, and this angle is very slowly decreasing in a cycle that spans about 41,000 years. It was last at its maximum tilt about 10,000 years ago and will reach its minimum tilt about 10,000 years from now. As obliquity decreases, it gradually helps make our seasons milder, resulting in increasingly warmer winters, and cooler summers that gradually, over time, allow snow and ice at high latitudes to build up into large ice sheets. As ice cover increases, it reflects more of the Sun’s energy back into space, promoting even further cooling.

 

Play Video

Credit: NASA/JPL-Caltech

Precession – As Earth rotates, it wobbles slightly upon its rotational axis, like a slightly off-center spinning toy top. This wobble is due to tidal forces caused by the gravitational influences of the Sun and Moon that cause Earth to bulge at the equator, affecting its rotation. The trend in the direction of this wobble relative to the fixed positions of stars is known as axial precession. The cycle of axial precession spans about 25,771.5 years.

Axial precession makes seasonal contrasts more extreme in one hemisphere and less extreme in the other. Currently perihelion occurs during winter in the Northern Hemisphere and in summer in the Southern Hemisphere. This makes Southern Hemisphere summers hotter and moderates Northern Hemisphere seasonal variations. But in about 13,000 years, axial precession will cause these conditions to flip, with the Northern Hemisphere seeing more extremes in solar radiation and the Southern Hemisphere experiencing more moderate seasonal variations.

Precession does affect seasonal timing relative to Earth's closest/farthest points around the Sun. However, the modern calendar system ties itself to the seasons, and so, for example, the Northern Hemisphere winter will never occur in July. Today Earth’s North Stars are Polaris and Polaris Australis, but a couple of thousand years ago, they were Kochab and Pherkad.

There’s also apsidal precession. Not only does Earth wobble on its rotational axis, but Earth’s entire orbital ellipse – that is, the oval-shaped path Earth follows in its orbit around the Sun — also wobbles irregularly, primarily due to its interactions with Jupiter and Saturn. The cycle of apsidal precession spans about 112,000 years. Apsidal precession changes the orientation of Earth’s orbit relative to the ecliptic plane.

The combined effects of axial and apsidal precession result in an overall precession cycle spanning about 23,000 years on average.

A Climate Time Machine

The small changes set in motion by Milankovitch cycles operate separately and together to influence Earth’s climate over very long timespans, leading to larger changes in our climate over tens of thousands to hundreds of thousands of years. Milankovitch combined the cycles to create a comprehensive mathematical model for calculating differences in solar radiation at various Earth latitudes along with corresponding surface temperatures. The model is sort of like a climate time machine: it can be run backward and forward to examine past and future climate conditions.

Milankovitch assumed changes in radiation at some latitudes and in some seasons are more important than others to the growth and retreat of ice sheets. In addition, it was his belief that obliquity was the most important of the three cycles for climate, because it affects the amount of insolation in Earth’s northern high-latitude regions during summer (the relative role of precession versus obliquity is still a matter of scientific study).

He calculated that Ice Ages occur approximately every 41,000 years. Subsequent research confirms that they did occur at 41,000-year intervals between one and three million years ago. But about 800,000 years ago, the cycle of Ice Ages lengthened to 100,000 years, matching Earth’s eccentricity cycle. While various theories have been proposed to explain this transition, scientists do not yet have a clear answer.

Milankovitch’s work was supported by other researchers of his time, and he authored numerous publications on his hypothesis. But it wasn’t until about 10 years after his death in 1958 that the global science community began to take serious notice of his theory. In 1976, a study in the journal Science by Hays et al. using deep-sea sediment cores found that Milankovitch cycles correspond with periods of major climate change over the past 450,000 years, with Ice Ages occurring when Earth was undergoing different stages of orbital variation.

Several other projects and studies have also upheld the validity of Milankovitch’s work, including research using data from ice cores in Greenland and Antarctica that has provided strong evidence of Milankovitch cycles going back many hundreds of thousands of years. In addition, his work has been embraced by the National Research Council of the U.S. National Academy of Sciences.

Scientific research to better understand the mechanisms that cause changes in Earth’s rotation and how specifically Milankovitch cycles combine to affect climate is ongoing. But the theory that they drive the timing of glacial-interglacial cycles is well accepted.

Further Reading: Why Milankovitch Cycles Can’t Explain Earth’s Current Warming

Edited April 10 by Witness1970

[Witness1970]

On 1/31/2026 at 5:10 PM, Barbllm said:

Found this on another website. These are the patterns made by various planetary orbits:

 

I don't understand these photos.  I can not think of any point of view where these patterns would show up.

[Witness1970]

 

[Witness1970]

Any two objects that orbit each other tend to slowly become tidally locked.  Mercury is tidally locked to the sun, always having one side turned toward the sun.  The moon is tidally locked to the earth.  Pluto and Charon are tidally locked to each other.  The earth's orbit is slowing down because of the moon's gravity.  It will take billions of years for the earth to become tidally locked to the moon, because the earth is much larger.  Of course, Jehovah could do something before that time so that the earth never becomes tidally locked to the moon.  (There is no "dark side of the moon" because the moon has the same face toward the earth but different sides of the moon face the sun as it orbits earth.

[Witness1970]

https://www.msn.com/en-us/news/technology/god-of-chaos-asteroid-apophis-approaches-earth-what-scientists-expect-in-2029/vi-AA20SeGe?ocid=msedgdhp&pc=ACTS&cvid=69e3900ad082405a8280eb95171ef66d&ei=42

 

Apophis asteroid. Who cares where the name came from

[Witness1970]

What Is the Biggest Galaxy in Our Universe?

January 6, 2026

The universe contains billions of galaxies, ranging from small dwarf galaxies to colossal systems stretching across millions of light-years. Determining the “biggest” galaxy requires understanding how astronomers measure these immense, ill-defined objects. The vastness of space continually challenges our perception of scale, driving the search for the most extreme structures created by the cosmos.

How Astronomers Define Size

Determining the largest galaxy is complicated because “size” in astronomy can refer to several different metrics. The most intuitive measure is the physical diameter or stellar extent, which is the distance across the visible body of the galaxy. Since galaxies lack sharp edges, astronomers often define this size using an isophotal diameter, which measures the extent down to a specific, faint level of brightness.

Another definition of size focuses on mass, which includes the vast, invisible halo of dark matter surrounding every galaxy. While the Milky Way contains about 100 billion visible stars, its total mass is substantially greater due to dark matter. For many astronomers, a galaxy’s true size is best represented by its total gravitational influence.

A third, specialized measure considers the immense radio lobe extent produced by active galaxies with powerful central black holes. These galaxies blast jets of plasma millions of light-years into space, forming giant lobes visible only to radio telescopes. For instance, the galaxy Alcyoneus has radio structures spanning over 16 million light-years, making it the largest known single-galaxy structure in the universe.

Identifying the Largest Known Galaxy

When defined by the extent of its stellar light, the largest known system is the supergiant elliptical galaxy IC 1101. This colossal structure resides at the center of the Abell 2029 galaxy cluster, about one billion light-years from Earth. IC 1101 is classified as a cD galaxy (central dominant galaxy), known for its vast, diffuse envelope of stars.

Estimates of its diameter vary, but the galaxy’s visible stellar halo stretches between 4 and 6 million light-years across. For perspective, the Milky Way is only about 100,000 light-years in diameter, meaning IC 1101 is dozens of times wider. It is estimated to contain over 100 trillion stars, dwarfing the Milky Way’s population.

IC 1101 achieved this immense size through galactic cannibalism, where a galaxy at the center of a dense cluster absorbs smaller galaxies. Over billions of years, numerous mergers built this elliptical behemoth, leaving it with a yellowish-red hue indicative of an older stellar population. This accumulation of matter is typical for the most massive galaxies found in the densest regions of the universe.

Calculating Cosmic Distances

Determining the physical size of IC 1101 requires astronomers to first accurately measure its distance from Earth using the cosmic distance ladder. The initial rung of this ladder uses standard candles, astronomical objects with a known intrinsic brightness. For relatively nearby galaxies, astronomers use Cepheid variable stars, whose pulsation period is directly related to their absolute luminosity.

For more distant objects like IC 1101, Type Ia supernovae serve as the preferred standard candle. These stellar explosions reach a consistent peak luminosity, allowing scientists to calculate distance by comparing this known absolute brightness to their observed apparent brightness. The difference reveals the distance, based on the inverse square law of light.

For the most remote galaxies, the primary method relies on measuring redshift and applying Hubble’s Law. Redshift is the stretching of light waves toward the red end of the spectrum as an object moves away, a consequence of the universe’s expansion. The greater the redshift, the faster the galaxy is moving away, and according to Hubble’s Law, the greater its distance.

Once the distance is accurately established, astronomers use simple trigonometry, relating the galaxy’s observed angular size in the sky to its calculated distance, to determine its physical diameter in light-years. This combination of standard candles to calibrate the distance-redshift relationship allows for the precise measurement of the most distant and largest galaxies.

Edited 2 hours ago by Witness1970

[Witness1970]

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Euclid Discovers Most Ancient Quasars in the Universe

Astronomers using the European Space Agency’s Euclid space telescope have found 31 of the most ancient quasars ever observed, including two that are the oldest ever recorded Phys.org+1.

What are these quasars?

Quasars are extremely luminous cores of galaxies powered by supermassive black holes at their centers. When vast amounts of gas and dust spiral into the black hole, extreme friction heats the material to millions of degrees, producing light that can be hundreds to thousands of times brighter than the host galaxy Phys.org+1. They are among the most energetic events in the cosmos.

How old are they?

The two most distant quasars discovered shine as they were 670 million years after the Big Bang, when the universe was only 5% of its current age Phys.org+1. Their light has traveled for over 12 billion years to reach Earth. The farthest of these is EUCL J172902.75+641018.1 (redshift 7.77), and the second-farthest is EUCL J125308.55+705432.3 (redshift 7.69) Phys.org.

Why are they important?

These primordial quasars are rare because:

• Few galaxies had grown large enough to host supermassive black holes.

• Their light is faint and can be mistaken for nearby stars Phys.org+1.

By studying them, astronomers can learn how the first supermassive black holes and galaxies formed so quickly after the Big Bang — one of the biggest mysteries in astrophysics Phys.org+1.

How were they found?

Launched in 2023, Euclid is equipped with cameras sensitive to both visible and near-infrared light, allowing it to detect faint, distant objects that ground-based telescopes miss Yahoo. Its Euclid Wide Survey began in 2024 and is mapping about a third of the sky. In just two years, it has found 31 ancient quasars, far more than previous decades combined Space.com.

What’s next?

These discoveries mark a shift from finding only the brightest outliers to studying the typical early-universe quasar population. This will help scientists understand the growth rates of black holes and their role in shaping early galaxies Yahoo. The findings also inform future missions like NASA’s Nancy Grace Roman Space Telescope, which will further explore dark energy and early cosmic structure Science Mission Directorate.

In short, Euclid’s haul of ancient quasars is a major leap forward in our ability to probe the universe’s infancy and the origins of its most massive black holes.

[Witness1970]

WD 1856 b: A Jupiter‑Sized Planet Surviving Its Star’s Death

Astronomers have found the first confirmed case of a planet with an atmosphere orbiting a white dwarf — a burned‑out core of a dead Sun‑like star — and the system offers a rare glimpse into the future of planetary systems like our own Yahoo+1.

Discovery and Location

The planet, WD 1856 b, was discovered in 2020 by NASA’s TESS and Spitzer telescopes. It orbits the white dwarf WD 1856+534, about 80 light‑years away, every 34 hours at a distance roughly 50 times closer than Earth is to the Sun Science Mission Directorate+1. The white dwarf is about the size of Earth, while WD 1856 b is about the size of Jupiter but seven times larger than its star Science Mission Directorate.

How It Survived

When its host star was a red giant, it should have engulfed and destroyed any nearby planets. Two main survival theories exist:

• Ingestion and ejection: The planet was swallowed by the red giant and somehow survived inside, then ejected as the star collapsed into a white dwarf Yahoo.

• Gravitational migration: The planet migrated inward later, possibly due to gravitational interactions with other bodies in the system Phys.org.

The planet’s unexpectedly high temperature (~126 °C) — hotter than expected from white dwarf light alone — helped scientists reconstruct its thermal history and support the migration theory European Space Agency.

Atmosphere and Composition

Using NASA’s James Webb Space Telescope, researchers observed a grazing transit where the planet’s atmosphere partially blocked starlight. They detected:

• Methane and haze particles in the atmosphere Cornell Chronicle+1.

• A transmission spectrum showing methane absorption bands and haze slopes, giving it a color similar to Saturn’s moon Titan Cornell Chronicle.

• A mass between 4 and 11 times Jupiter’s Cornell Chronicle.

The atmosphere’s warmth suggests ongoing internal heat sources, possibly from residual formation energy or gravitational contraction.

Why It Matters

WD 1856 b is the first confirmed atmosphere around a close‑orbiting white dwarf planet, opening a new window into the long‑term fate of planetary systems Yahoo+1. It shows that even in the final stages of a star’s life, some planets can survive and retain atmospheres, expanding the possible scenarios for where habitable zones might exist in the universe Phys.org.

In short: WD 1856 b is a rare, warm, methane‑rich gas giant that somehow survived its star’s death and now orbits a white dwarf with a detectable atmosphere — a cosmic time capsule for the future of our own Solar System.