The oldest continents in the Milky Way may be 5 billion years older than Earth's

[Admin]

Several exoplanets at the edge of our galaxy could have formed continents — and advanced life — 5 billion years earlier than Earth, new research suggests.

The oldest continents in the Milky Way may be 5 billion years older than Earth's : Read more

 

[rod]

Specific exoplanets that fit the model in the reference I did not see, When were the First Exocontinents?, https://iopscience.iop.org/article/10.3847/2515-5172/acf91a, Sep-2023. The space.com article cited some exoplanets though.

This exoplanet is in the space.com article, HD 219134b. The report stated, "She found that the first continents formed around nearby sun-like stars up to 2 billion years earlier than Earth's plate tectonics began. The oldest continents of a nearby star are around HD 4614, about 20 light-years from Earth. Earth's starting time, however, is average for our cosmic neighborhood." "Two stars stand out from the pack, though: The planets of two stars a bit smaller than our sun (HD 76932 and HD 201891), located 70 to 110 light-years away from us respectively in a region known as the "thick disk", could have formed continents up to 5 billion years earlier than us. Based on her sample of just 29 stars and astronomers' current best estimates for how likely a planet is to be habitable, Greaves wrote, "there could be two systems in this sample alone with biospheres more advanced than here on Earth."

IMO, this is quite a report and model for astrobiology Continents on some exoplanets perhaps and perhaps more advanced *biospheres* than on Earth.

HD 219134 b is listed in a 7 exoplanet system, https://exoplanet.eu/catalog/hd_219134_b--2415/, the nasa archive site shows 6 confirmed exoplanets, https://exoplanetarchive.ipac.caltech.edu/cgi-bin/TblView/nph-tblView?app=ExoTbls&config=PS

HD 76932 is not on the confirmed exoplanet lists, https://exoplanet.eu/home/, and https://exoplanetarchive.ipac.caltech.edu/index.html, and HD 201891 does not have a confirmed exoplanet on these two sites I use.

Edit, HD 4614 this star is not found on the confirmed exoplanet lists too.

 

[Justman]

Hi there I am new here....

Please explain how this was established. Who measured it 5 billion years ago or what scientific formulas was used to measure.

Who placed the instruments on these continents there to be measured.

Dont get me wrong, the one thing I fail to understand is that someone can measure something that is 5 billion or 5 million years old. Whiles recent tech that was to measure it was only recently develop. If we say we measure something then someone or some tech had to be there during the time we say it existed otherwise our fornulas is wrong. Then the formulas was created just to tell is what we want to hear.

For instance a 100 years back we invented the telephone, I now can say that the telephone is 100 years and odd old or the internet is 100 years old and the speed has evolved in such way as there was something to measure it or someone was there who wrote about it.

Now with that said who was 5 billion years on earth who measured the continents in out of space and if that is so then our tech is notnew but old has it was used 5 billion years back.

As I said I am new to this please help me understand

 

[billslugg]

The only information they have is from spectral lines. From these they can tell what a star is made of and its age. Computer models then solve for how long it took for planets to form, how hot they got and thus when plate tectonics began.

 

[rod]

Keep in mind the exoplanet sites, more than 5500 confirmed now. None have been shown to have continents like Earth for example, at least nothing imaged showing this or spectroscopic analysis showing land masses and seas for example. Models in science are good but always need follow up observations from nature showing the models and assumptions used in various simulations are factual and accurate. In my post #2, what caught my attention after reading this article, some stars listed in the report, do not have confirmed exoplanets reported orbiting. As post #1 in the article states, "could have formed continents — and advanced life" None confirmed presently among the exoplanets documented now with continents and *advanced life* or any life on them.

 

[billslugg]

Direct imaging of continents is going to be very difficult. At the distance of the nearest star, 4e16 m, a 1000 km continent would subtend but 1e-9 degree. Arc tan is 2.5e-11, inverted is 4e10, times wavelength of green light 600 nm, the mirror would need to be 24 km in diameter. LIGO is performing much better than that I believe. It might be possible through interferometry.

 

[Forrester]

Several exoplanets at the edge of our galaxy could have formed continents — and advanced life — 5 billion years earlier than Earth, new research suggests.

The oldest continents in the Milky Way may be 5 billion years older than Earth's : Read more

The article says by the decay of radioactive isotopes.

 

[Questioner]

It is always mentioned that radioactive decay heat sustains the molten activity,
but it seems rare that the tidal friction heating is included.
I would imagine tidal friction contributes some percentage of heat in Earth's case.
And that friction source must have been even greater when the moon was orbiting closer to the Earth.
Many outer moons in the Solar system are largely kept/made molten by tidal friction.

 

[Questioner]

It's borderline neurotic,
but i worry about the 4cm the moon is orbiting further away each year.
Keeping our magnetic field intact keeps the life sustaining atmosphere mostly in place.

Use ALL the gravity assist from the moon as possible.
It's all 'free' energy.
Free AND beneficial.

 

[billslugg]

The Moon drains energy from the Earth. The Moon's gravity raises a tidal bulge on the side of Earth facing the Moon (bigger than the one on the side away from the Moon), the Earth's rotation sweeps some of that bulge eastward, this mass exerts a pull on the Moon with a tiny vector force in the direction the Moon is moving. This acceleration raises the Moon's orbit about 4" per year, slows the Earth's rotation down by about a second. Eventually the Moon will slow the Earth enough they will become tidally locked.

 

[Questioner]

The (non-molten) moon is already tidally locked to Earth.
My impression is that locking happens because there is some fixed higher density point(s) that sort of drag on rotational movement.
Like a slightly elliptical shape that spends a little extra time as its long axis points towards the source of gravity & may eventually settle there in the gravity trough between objects.
If the Earth is molten to a good degree i would think it would resist locking to some degree because higher density places would shift & change on an ongoing basis.
It wouldn't have as fixed a density location to 'snag' on the gravity trough.

Also the question of whether the shrinking gravity trough to moon because of its outward spiral will become insignificant before it has a lot more effect on Earth's rotation.
The moon was only 50,000 miles from Earth after the binary collision formed it and gave Earth its spin.
It's now 5 times as far from Earth.

 

[billslugg]

Yes, the Moon is tidally locked to Earth but the Earth is not locked to the Moon. Locking occurs because the center of mass is not coincident with the measured center. Too much mass on one side. Modelling has shown the Earth will lock up in about 3 or 4 billion years. When this happens the Moon will no longer recede.

 

[Classical Motion]

I believe we are looking at orbits in the wrong manner. I believe the angular momenta transferred to the moon......is using the wrong rotation.

Draw a straight line from center of earth to center of moon. At the center of the moon, draw another radius. That radius swings perpendicular to the orbital direction. Giving an apogee and a perigee. And the moon, makes one of those small rotations.....for every rotation around earth. Completing a one turn helix during each rotation. The moon makes one long stretched out rotation....during the large rotation around earth. A turn inside of a turn.

It's the small perpendicular rotation that expands when angular momenta is transferred. NOT an elliptical trajectory.

It's just my discernment of motion. From watching moons fly thru debris fields.

The center-line of moon's orbit does move out from the earth, due to decreasing g of the sun.

Just like the center-line of the earth and the other planets do. And they are one turn helices also.