Starship Asterisk*

[quote=shaileshs post_id=331554 time=1686085600 user_id=143908]
[quote=MelvzLuster post_id=331548 time=1686075729 user_id=146742]
When the Sun gets nova, our Earth will be eaten and that will happen in 3937 as prophesized by Nostradamus as the end of the world. This can be scientifically proven by Arthur Clarke's novel The Songs of Distant Earth.
[/quote]

Lol.. Whole world was going to come to an end on 21st Dec 2012.. And we are here today.. I'm surprised (and sad) that there are people believing such BS predictions but I respect that everyone has a right to believe whatever they want to believe..
[/quote]

Except when the person is the former president of the U.S. of A.! :ssmile:

[quote="Chris Peterson" post_id=331555 time=1686086030 user_id=117706]
[quote=johnnydeep post_id=331551 time=1686082489 user_id=132061]
The last sentence doesn't seem to mesh with the Sun becoming a red giant in 5 Gy and engulfing the Earth. Unless the Earth will indeed be engulfed in 5 Gy, yet will still exist as a waterless molten rock for another 3 Gy until spiraling into the Sun's interior?
[/quote]

The outer atmosphere of a red giant is practically a vacuum, and quite likely not hot enough to melt rock.
[/quote]

Point taken, But I presume the atmosphere and oceans will still be heated or blown away, right? Although I can't really see how a near vacuum would be able to that either!

[quote=longtry post_id=331561 time=1686111629 user_id=144549]
I find the animation/simulation not convincing. From the accompanied text and links, I can't really tell if the planet is a rocky or gassy one, but in any case it can hardly be any more than 1% the mass of the star. Also, I assume that this "Sun-like" star has run out of H and is now fusing He or something, thus the red giant depiction. Now, a <1% of mass spiraling into the envelope of 99% mass of an almost identical composition can trigger a change in color and dramatic expansion (looks like 3.5-4 times the old radius, which mean ~50 times volume)? It hardly makes sense. Could someone correct me if I'm wrong somewhere?
[/quote]

I'd suggest that you read the paper describing this event. https://www.nature.com/articles/s41586-023-05842-x.epdf?sharing_token=XpHwbzgQUo43KmLrQl56-NRgN0jAjWel9jnR3ZoTv0OCbSlJfNYHXYBBBki73pgzs92RGkyR__x4DPfnoaqk-bF6f4Kjxy1Q5K4lZPsxhiURgkCKD4WUMuwz8-AFEO3kh0XXSOD_PSKBpYsuPnWkFhNQXQvhKJqRlNjxWKmjXbQ%3D

I find the animation/simulation not convincing. From the accompanied text and links, I can't really tell if the planet is a rocky or gassy one, but in any case it can hardly be any more than 1% the mass of the star. Also, I assume that this "Sun-like" star has run out of H and is now fusing He or something, thus the red giant depiction. Now, a <1% of mass spiraling into the envelope of 99% mass of an almost identical composition can trigger a change in color and dramatic expansion (looks like 3.5-4 times the old radius, which mean ~50 times volume)? It hardly makes sense. Could someone correct me if I'm wrong somewhere?

[quote=johnnydeep post_id=331551 time=1686082489 user_id=132061]
The last sentence doesn't seem to mesh with the Sun becoming a red giant in 5 Gy and engulfing the Earth. Unless the Earth will indeed be engulfed in 5 Gy, yet will still exist as a waterless molten rock for another 3 Gy until spiraling into the Sun's interior?
[/quote]

The outer atmosphere of a red giant is practically a vacuum, and quite likely not hot enough to melt rock.

[quote=MelvzLuster post_id=331548 time=1686075729 user_id=146742]
When the Sun gets nova, our Earth will be eaten and that will happen in 3937 as prophesized by Nostradamus as the end of the world. This can be scientifically proven by Arthur Clarke's novel The Songs of Distant Earth.
[/quote]

Lol.. Whole world was going to come to an end on 21st Dec 2012.. And we are here today.. I'm surprised (and sad) that there are people believing such BS predictions but I respect that everyone has a right to believe whatever they want to believe..

The last sentence doesn't seem to mesh with the Sun becoming a red giant in 5 Gy and engulfing the Earth. Unless the Earth will indeed be engulfed in 5 Gy, yet will still exist as a waterless molten rock for another 3 Gy until spiraling into the Sun's interior?

When the Sun gets nova, our Earth will be eaten and that will happen in 3937 as prophesized by Nostradamus as the end of the world. This can be scientifically proven by Arthur Clarke's novel The Songs of Distant Earth.

[quote=Ann post_id=331533 time=1686029791 user_id=129702]
Humanity has witnessed one other event where a star possibly ate a planet, namely in the case of V838 Monocerotis:


[youtube]https://www.youtube.com/watch?v=CJiqjppxToI[/youtube]


The accepted view appears to be that the incredible brightening of V838 Mon was caused by the merger of two stars. However, the "star eats planet" hypothesis has also been put forth.


[quote][url=https://en.wikipedia.org/wiki/V838_Monocerotis#Planetary_capture_event]Wikipedia[/url] wrote:

Another possibility is that V838 Monocerotis may have swallowed its giant planets. If one of the planets entered into the atmosphere of the star, the stellar atmosphere would have begun slowing down the planet. As the planet penetrated deeper into the atmosphere, friction would become stronger and kinetic energy would be released into the star more rapidly. The star's envelope would then warm up enough to trigger deuterium fusion, which would lead to rapid expansion. The later peaks may then have occurred when two other planets entered into the expanded envelope. The authors of this model calculate that every year about 0.4 planetary capture events occur in Sun-like stars in the Milky Way galaxy, whereas for massive stars like V838 Monocerotis the rate is approximately 0.5–2.5 events per year.[/quote]

Ann
[/quote]

ThanX Ann

Your comparison with V838 Monocerotis is extremely exciting. But apparently there is no clear scientific explanation. At least 6 different explanatory models are listed in the English Wikipedia entry.

[img]https://upload.wikimedia.org/wikipedia/commons/thumb/c/c2/V838_Mon_1989-2006.gif/440px-V838_Mon_1989-2006.gif[/img]

What is still hard to understand is the principle of the light echo in this specific case.

"In the case of V838 Monocerotis, the light echo produced was unprecedented and is well documented in images taken by the Hubble Space Telescope. While the photos appear to depict an expanding spherical shell of debris, they are actually formed by the illumination of an ever-expanding ellipsoid with the progenitor star at one focus and the observer at the other. Hence, despite appearances, the structures in these photos are actually concave toward the viewer." [url]https://en.wikipedia.org/wiki/V838_Monocerotis[/url]

There are a lot of interessting questions:

[b]1) Why does the flash of light expand in the form of an ellipsoid and not a sphere?[/b]
ChatGPT: The flash of light from V838 Monocerotis expands in the form of an ellipsoid rather than a sphere due to the interaction of the light with surrounding dust particles. As the light from the initial outburst travels through the dust cloud surrounding the star, it scatters off the particles in different directions. This scattering process is not uniform in all directions, resulting in an elongated or ellipsoidal shape rather than a symmetric spherical shape.

[b]2) And I assume that "the viewer" means us earthlings. Isn't that a bit too much of a coincidence that the only accurately documented novae (?) in the last 100 years aims exactly in the direction of earth, even if x other orientations would have been possible?[/b]
ChatGPT: The term "the viewer" typically refers to the observer or the person viewing the phenomenon, which in the case of V838 Monocerotis would indeed be Earthlings or observers on Earth. It may seem coincidental that the event is accurately documented and aimed towards Earth, but it is important to note that there are countless stars and novae in the universe, and we happen to observe only a small fraction of them. The chances of any given event being observed from Earth are relatively low. V838 Monocerotis was an exceptional case where we happened to have a fortunate viewing angle, allowing us to capture detailed observations.

[b]3) The clouds of dust visible in the time-lapse are not moving, but are existing and are only illuminated by the spreading lightning?[/b]
ChatGPT: The clouds of dust visible in the time-lapse images of V838 Monocerotis are not actually stationary. They are present in the vicinity of the star and are illuminated by the expanding light echo. The dust clouds may appear static in the images because the timescales of the changes in the dust cloud structure are much longer compared to the rapid expansion of the light echo. However, over longer periods of time, these dust clouds can evolve and disperse due to various physical processes in space.

[b]4) Why can't I calculate the exact distance when I can measure the time it takes for the light echo to propagate at right angles to the viewer?[/b]
ChatGPT: Calculating the exact distance to an object solely based on the time it takes for the light echo to propagate at right angles to the viewer can be challenging. The light echo's apparent expansion depends not only on the distance to the object but also on the geometry of the surrounding medium, such as the distribution of dust particles. Additionally, the light echo can be affected by interactions with the interstellar medium, which can cause changes in its shape and intensity. To determine the precise distance, astronomers typically use a combination of observational techniques, including parallax measurements, spectroscopic analysis, and other distance indicators specific to the type of object being studied.

20 second to wait. Just crazy. Well done my friend.

i like it fluffy :P
[img2]https://live.staticflickr.com/65535/52174049543_5707b8a85a_c.jpg[/img2]
[size=85]bigg: [url]https://live.staticflickr.com/65535/52174049543_9bcc905ee1_o.jpg[/url]
jac berne (flickr)[/size]

To be honest, didn't find this at all any interesting. Gas (planet) merging into gas (Star). No traces left behind.. What's the big deal ? Nothing spectacular, no dent.. like mixing river water into ocean..

Also not sure why in 8B years earth will fall into Sun, I thought the Sun was expected to die in 5B years consuming Earth and even Mars during it's late stage expansion.. Hopefully by then humanity has long left Earth and even Solar system for that matter.

[quote="orin stepanek" post_id=331540 time=1686057288 user_id=100812]
1-star-eats-planet-16.jpg,
Oh what a horrible way to die! :mrgreen:
And 8 billion years from now that may happen to Earth? wow!
[/quote]

In 8 billion years the Earth will be a desiccated cinder, devoid of life. And the star that got eaten was a gas giant nearly as hot as a star itself, so similarly devoid of life.

[attachment=1]1-star-eats-planet-16.jpg[/attachment],
Oh what a horrible way to die! :mrgreen:
And 8 billion years from now that may happen to Earth? wow!
[attachment=0]15634745431_af629b9374.jpg[/attachment]
You ate the whole planet? :D

[quote=LeighGus post_id=331538 time=1686056024 user_id=142205]
"One day, about eight billion years from now, planet Earth may spiral into our Sun."

By that time our sun may be dead by about 3 billion years or so and be a white dwarf, correct? So what would happen then? Is there a video of such a merger? I've also read on APOD multiple times that Earth may not survive the suns red giant phase. Space.com also suggests this:

https://www.space.com/14732-sun-burns-star-death.html

Leigh
[/quote]

There would be no mechanism for planets to decay into a white dwarf. That would be a very stable system. The Earth could orbit [i]inside [/i]the Sun in its red giant phase for a long time, slowly losing energy and moving inwards. But if the Sun contracted fast enough, that would leave the Earth once again in a stable orbit, ultimately around a white dwarf.

"One day, about eight billion years from now, planet Earth may spiral into our Sun."

By that time our sun may be dead by about 3 billion years or so and be a white dwarf, correct? So what would happen then? Is there a video of such a merger? I've also read on APOD multiple times that Earth may not survive the suns red giant phase. Space.com also suggests this:

https://www.space.com/14732-sun-burns-star-death.html

Leigh

How long does it take for this process to happen?

Humanity has witnessed one other event where a star possibly ate a planet, namely in the case of V838 Monocerotis:


[youtube]https://www.youtube.com/watch?v=CJiqjppxToI[/youtube]


The accepted view appears to be that the incredible brightening of V838 Mon was caused by the merger of two stars. However, the "star eats planet" hypothesis has also been put forth.


[quote][url=https://en.wikipedia.org/wiki/V838_Monocerotis#Planetary_capture_event]Wikipedia[/url] wrote:

Another possibility is that V838 Monocerotis may have swallowed its giant planets. If one of the planets entered into the atmosphere of the star, the stellar atmosphere would have begun slowing down the planet. As the planet penetrated deeper into the atmosphere, friction would become stronger and kinetic energy would be released into the star more rapidly. The star's envelope would then warm up enough to trigger deuterium fusion, which would lead to rapid expansion. The later peaks may then have occurred when two other planets entered into the expanded envelope. The authors of this model calculate that every year about 0.4 planetary capture events occur in Sun-like stars in the Milky Way galaxy, whereas for massive stars like V838 Monocerotis the rate is approximately 0.5–2.5 events per year.[/quote]

Ann

[url=https://apod.nasa.gov/apod/ap230606.html] [img]https://apod.nasa.gov/apod/calendar/S_230606.jpg[/img] [size=150]Star Eats Planet[/size][/url]

[b] Explanation: [/b] It’s [url=https://youtu.be/8OyBtMPqpNY?t=48]the end[/url] of a world as we know it. Specifically, the Sun-like star [url=https://www.caltech.edu/about/news/star-eats-planet-brightens-dramatically]ZTF SLRN-2020[/url] was seen eating one of its own planets. Although many a planet eventually dies by spiraling into their central star, the [url=https://www.nature.com/articles/s41586-023-05842-x]2020 event[/url], involving a Jupiter-like planet, was the first time it was [url=https://www.nasa.gov/feature/jpl/caught-in-the-act-astronomers-detect-a-star-devouring-a-planet]seen directly[/url]. The star [url=https://en.wikipedia.org/wiki/Zwicky_Transient_Facility]ZTF[/url] SLRN-2020 lies about 12,000 [url=https://spaceplace.nasa.gov/light-year/en/]light year[/url]s from the Sun toward the constellation of the Eagle ([url=https://en.wikipedia.org/wiki/Aquila_(constellation)]Aquila[/url]). In the [url=https://caltech.app.box.com/v/ZTF-NEOWISE-STAR-PLANET]featured animated illustration[/url] of the incident, the gas planet's atmosphere is first pictured being stripped away as it skims along the outskirts of the attracting star. Some of the planet's gas is absorbed into the star's atmosphere, while other gas is [url=https://apod.nasa.gov/apod/ap210427.html]expelled into space[/url]. By the video's end, the [url=https://live.staticflickr.com/5613/15634745431_af629b9374.jpg]planet is completely engulfed[/url] and falls into the star's center, causing the star's outer atmosphere to briefly expand, heat up, and brighten. One day, [url=https://ui.adsabs.harvard.edu/abs/2008MNRAS.386..155S/abstract]about eight billion years[/url] from now, planet [url=https://apod.nasa.gov/apod/ap220206.html]Earth[/url] may spiral into our [url=https://solarsystem.nasa.gov/solar-system/sun/overview/]Sun[/url].


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