Fate of the Universe

This is the last of dozens of other academic discussions this writer submitted for a course on Astronomy: Exploring the University at the University of Oxford 

Fate of the Universe forum

by lim ju boo 

My Personal View on Fate of The Universe

As promised last night in our regular forum discussion, I like to pose a question and discuss a very important issue on how the Universe will end

Much has been written on the fate of the Universe whether its expansion will go on forever bearing in mind the Hubble “constant” on the rate of expansion, currently 70 km/s that can be revised

However, the constant gravitational pull of all the galaxies in the Universe is universal. It can act as a brake on the inertia of expansion. This of course astronomers would argue depends on the critical mass and density of materials available

But if you were to ask my opinion even though mine may be amateurish, I would think how much mass would not matter in the final day of the Universe, because to my understanding,  gravity is persistent and will always be there as long there are still matter in the Universe even if all the galaxies have burnt their fuel away and turned into an aggregation of degenerate dwarf and neutron stars, or bloated up into giant red stars.  

But I believe  all may eventually clumped together into super huge and super massive black holes like soapy foams aggregating together and collapsing into bigger bubbles on a wet soapy floor 

To my thinking  the total mass in the final days of the Universe maybe less than during the first few moments of the Big Bang because the hydrogen is converted into fusion energy and  helium and other elements. This mass into energy conversion will cause the stars and galaxies to lose mass

Even if all the fuel runs out in this energy conversion, the remnants of mass will still be there where gravity can still act, be they dwarf, red giants, neutrons stars or black holes.

To the best of my understanding in Newtonian physics, as long as there is matter, gravity will be present, and where there is gravity there will always be an attractant force to bring everything together,  albeit gravitational force is the weakest compared with nuclear and electromagnetic forces.

Gravitational forces are eternally present and persistent as long as there are matter and mass in the Universe. How can matter or energy be destroyed except through conversion from one to the other. The net is always the same.

This unyielding force will continue to slow down the inertia of the galactic expansion, and finally drag all the dead galaxies, dark matter, whatever, and all their collective masses or densities together with a force acting inversely as the square of their distances no matter how far they are apart, and finally bring them together as they were before the Big Bang 

Hence, I don’t think density and amount of matter has any say when the eternal force of gravity acts

This is just how I reason it logically, but cosmologists may have their more advanced views to disagree 

Thus the present cooler Universe at just 3 Kelvin between the void and emptiness of intergalactic spaces may begin to warm up hotter and hotter at the last moments  of life of the Universe till the Big Crunch or Big Collapse when it shall be destroyed with fervent heat.

 But this scenario may be repeated again with another Big Bang, a Big Crunch… etc. We will now have a Pulsating Universe like a beating heart with a new heaven and a new earth with each pulse

This is from the scientific point of view if I can reason this scenario reasonably.

Now let me reveal what is written in the Bible.

“But the day of the Lord will come as a thief in the night; in the which the heavens shall pass away with a great noise, and the elements shall melt with fervent heat, the earth also and the works that are therein shall be burned up” (2 Peter 3:10)

Then I saw “a new heaven and a new earth,” for the first heaven and the first earth had passed away, and there was no longer any sea (Revelation 21)

My apologies for bringing religion and a Creator in this scientific discussion

Note it says “the elements shall melt with fervent heat’. Earlier at the beginning of this course we learn about heat from hydrogen into helium fusion and nucleosynthesis of the elements soon after the Big Bang.

Now the reverse event may come to pass when the elements already there shall come together and  melt with fervent heat when the Universe collapses into a single point in time, space and matter. What about that? This sounds very uncanny to me.  Does that verse ring a bell to Science?

Then further down in the last chapter in Revelation of the Bible it clearly says a new heaven and a new earth,” for the first heaven and the first earth had passed away, and there was NO LONGER ANY SEA (Revelation 21). Does that also ring another bell? 

In the Unit 8 on Astrobiology two weeks ago, we discussed the importance of water and life, and if we were to look for life in a habitable planet within the circum-stellar Goldilocks Zone, the presence of water is utmost important, that is life as we know it.

But we have no proper definition of what life is as yet. We have no clue if life in the form as we know it, or in other forms unknown to Science, probably spiritual form also exist in other worlds exist despite Frank Drake’s equation.

But this verse clearly says a new earth will have no sea (water). What about this? This is very errie and supernatural (for me at least).

Think this over. Sorry for bringing in religion or spiritual things into science in this discussion. Kindly do not ridicule or penalize me for the freedom of my own thinking or belief 

I can’t help it as they are just my personal thought just to share. You are free to disagree

Thank you peers and course mates in this course for reading. 

Thank you to Dr. Grant Miller too for teaching us 

Jb lim

Malaysia

The Concept of a Habitable Zone on Exoplanets

The Concept of a Habitable Zone on Exoplanets Q & A

by Ju Boo Lim - Friday, 25 October 2019, 9:37 AM

Number of replies: 15

Calculations on the Goldilocks Zone where Earth-like environment around a star may be possible:

Given the relative sizes of the Habitable Zones around stars which are relatively 0.25, 0.5, 5 and 10 times the luminosity of the Sun

Applying the equations for the given luminosity of the Sun

The Habitable Radius around a star:

0.25 x the luminosity of the Sun, it would 0.47 AU (inner radius), and 0.68 AU (outer radius)

0.5 x the luminosity of the Sun, it would 0.67 AU (inner radius), and 0.97 AU (outer radius)

5.0 x the luminosity of the Sun, it would be 2.13 AU (inner radius) and 0.3.0 AU (outer radius)

10 x the luminosity of the Sun, it would be 3.0 AU (inner radius) and 4.34 AU (outer radius)

AU = Astronomical Unit is Earth-Sun distance

 = 1.495 978 707×1011 metres, or about 150 million kilometres (93 million miles).

However in my personal thinking this may just be a theoretical mathematical-physical  concept, because for life to be possible in another planet it is not just the physical Earth-like environment like heat, light and water that are just right, but I think we also need to consider the presence of complex organic compounds in their correct constituents and configurations to start jump life.

Not just the presence of carbon, nitrogen, hydrogen and oxygen to form amino-acids and other organic compounds as in Miller and Harold Urey experiment, but much more complex than that, which is the ability for organic molecules to form DNA which is still not life, but merely the chemical foot-prints of life.

What I strongly believe than just the synthesis of nucleic acids and DNA, is the presence of “the spark of life” (whatever that is residing inside a living body) to “ignite” these chemical substances into life itself in order for any exoplanet or even planets in our own Solar System (other than our own Earth) to give rise to life itself, and continue to support it as on Earth.

Although I don’t mean to show disrespect to these mathematical formulae given by astronomers, I am only expressing the freedom of my own (scientific) thinking that the Goldilocks Zone is only a zone that may mimic Earth-like physical environments on an (exo)planet  if it is not too near or too far away from a parent star.

I hope I will not be penalized for my independent thinking

Thank you.

Lim ju boo

In reply to Ju Boo Lim

Re: The Concept of a Habitable Zone on Exoplanets Q & A

From Dr. Grant Miller University of Oxford  - Friday, 25 October 2019, 6:36 PM

Hi Lim,

Good post! You raise some important points. Of course just finding a planet in the "habitable zone" does not mean it will actually be inhabited. This depends on many other factors, but it's a good first step on the search. The one thing that underpins all life on Earth is the need for liquid water, so first we look for places where liquid water can exist, and everything else comes after that.

Now you may say that there's a possibility that life exists in some other way in the Universe without the presence of liquid water, but that is such a big unknown that it makes a lot more sense to start the search with what we do know and expand from there.

I hope that makes sense!

Cheers,

Grant

Microlensing of Light Curves of A Distant Planet

 by lim ju boo

University of Oxford 

An analysis of the light curve of the microlensing event PA-99-N2 suggests the presence of a planet orbiting a star in the Andromeda Galaxy (2.54 ± 0.11 Mly).

 In late January 2018, a team of scientists led by Xinyu Dai claimed to have discovered a collection of about 2,000 rogue planets in the quasar microlens RX J1131-1231, which is 3.8 billion light-years distant. The bodies range in mass from that of the Moon to several Jupiter masses.[

The most distant potentially habitable planet confirmed is Kepler-443b, at 2,540 light-years distant although the unconfirmed planet KOI-5889.01 is over 5,000 light-years distant.

(Source: https://en.wikipedia.org/wiki/List_of_exoplanet_extremes)

I can quite understand measuring the distances of whole galaxies that lie at the edge of an Observable Universe by their red shifts.

But detecting a non- radiating planet in the Andromeda Galaxy is a different thing.  The ability of detecting, observing, and measuring the presence of just a planet or a group of them in another galaxy at such a horrendous distances mentioned above is taking things to the extreme. One can hardly see individual stars in a distant galaxy, let alone detecting planets orbiting around them.

This feat is truly remarkable to my feeble mind. My hats off to those teams of astronomers 

This is “light years” in the advancement of astronomy since the last planet Pluto was discovered by Clyde William Tombaugh in in 1930

Cheers to all the astronomers!

Emptiness in Space?

In the introductory on the Big Bang, allow me to quote this passage below:

"our island Universe of a hundred billion stars – was merely one of many such galaxies separated by millions of light years of empty space"

How can that be? How can there be emptiness between the galaxies ?

First, Nature abhors a vacuum. I would have thought even in intergalactic spaces, there would be at least one hydrogen atom per cubic metre of space.

Even if there is none, or let me put this another way - what lies between the two hydrogen atoms in two cubic meters of space?

Answer: Empty?

 I would argue that there would be gravity in the space no matter how weak since the force of gravity falls off as the square of its distance (between two stars or between two galaxies)

As far as I know, gravity has no seam or boundary. It permeates seamlessly throughout the entire Universe no matter how weak between vast distances of intergalactic space

If my personal argument is not correct because the gravity would be so weak between two galaxies or stars, that it is almost not tangible (but not exactly zero), then we still have time there as part of the space-time continuum (Einstein Theory of Relatively)

To me, nothing in this entire Universe can be zero, empty or nothing.

There must always be something there even in a black hole such as temperature as postulated by Steven Hawking if I am not mistaken.

Once again Nature abhors a vacuum

I hope my thinking is sound?

lim ju boo

Malaysia

Merging Galactic Spirals Becomes Red

Reasons why merging of spirals becomes red

by Ju Boo Lim - Sunday, 6 October 2019, 3:13 PM

Number of replies: 10

Forum Discussion

University of Oxford 

I think this is quite simple to explain

Since the spiral arms of galaxies are new with new blue and hot population 1 stars, over time they slowly burn up their fuel and became less hot and older. Their spectrum shifts from blue hot to the cooler red colour

At the same time their spiral arms whatever their various tunning fork classification, became to merge or coalesce, maybe I guess due to the gravitational pull of their elliptical or oval centers which are more massive due to the crowd of metal poor population 2 stars  within their galactic nuclei.

When two spirals merging to form an elliptical galaxy they began to contain older red stars.

These "centralized stars" are cooler, older and redder  than the metal rich population 1 blue and hotter stars

As the population 1 stars grow older and redder in the spirals, they may merge to become ellipticals

 Their centres too became redder because they now contain larger content of old red stars

Older population 2 stars in the galactic nuclei  are less rich in metal content than newer population 1 stars in their spiral arms due to the blast of some massive stars in supernovae spilling out their metal contents from nucleosynthesis outwards to contaminate the gas clouds and dusts in the surroundings even before they can  form new less  metal-rich  stars.

I think the shortest way to answer this question is, hot blue spiral galaxies after merging they become older over time, and became cooler and redder.

In reply to Ju Boo Lim

Re: Reasons why merging of spirals becomes red

by Dr. Grant Miller, University of Oxford

 - Thursday, 10 October 2019, 5:06 PM

This is basically the right answer! Good work! The key is in what you pointed out at the end. Red stars are cooler and older, so if merging takes some time then those are the stars that will be left at the end, whereas more of the younger, hotter blue stars from the original spiral galaxies will have died off.

Collisions of Galaxies

I do agree that even in the event of a major merger between two galaxies, the chances of a star to star head on collision is highly unlikely

I believe the closest separation between two stars even in the crowded center of each galaxy would be at least half a light year apart giving practically no chance of any collision

What is possible are the immense spread of gas clouds that diffuse between the stars

Thus, an aggregation of clouds during a major galactic merger may give a higher chance of stellar formation due to their combined masses, at least this is just my belief

Reply from University of Oxford

In reply to Ju Boo Lim by Dr. Grant Miller PhD (Astrophysics), University of Oxford  - Thursday, 10 October 2019, 5:08 PM

This is right! Stars do not actually physically collide during galaxy mergers, but the gas density increases and this can lead to the formation of new stars.

Combined methods to confirm the presence of an exoplanet

Combined methods to confirm the presence of an exoplanet

by Ju Boo Lim - Sunday, 27 October 2019, 5:50 PM

Number of replies: 32

My feeling is, with the different methods used in detecting exoplanets, such as from the detection of "wobbles" to microlensing, it would be better if the discoverers use different methods to confirm  the same results of the  planet(s) revolving around the same parent star.

My feeling is sometimes it may be an illusion because the star-planet system is so far away and so small, and that visual observation can be highly subjective.

I am unsure, but I feel that temperature differences in the different layers of the Earth's atmosphere may distort images and movements with their twinkling effects

Instrumental observation and measurement is more objective and less likely to make mistakes

For instance, using a photometer to observe changes in light intensity during an occultation would be much more reliable than any stand-alone visual method

Thus I wonder how many  new exoplanets discovered so far has been investigated using multiple systems?