Showing posts with label Science. Show all posts
Showing posts with label Science. Show all posts

Thursday, August 17, 2023

Tour of the Solar System News, from Mercury to outer limits of the Solar System

 Let's take another tour of the Solar System with current news about each of our major objects.

Mercury Dramatic Flyby Confirms That Mercury's Radioactive Aurora Touches the Ground, backup link and source material.

VenusThe Founder of OceanGate Wants to Send 1,000 People to Colonize Venus, backup link.

Earth Why Nasa is exploring the deepest oceans on Earth, backup link.

Mars Mars helicopter Ingenuity breaks 3-month flight gap with 53rd Red Planet hop. backup link.

Ceres The Dwarf Planet on Our Doorstep, backup link.

Jupiter James Webb Space Telescope sees Jupiter moons in a new light, backup link.

Saturn 100-year 'megastorms' on Saturn shower the ringed planet in ammonia rain, backup link.

Uranus NASA's New Horizons will investigate Uranus from the rear (Neptune, too). Here's how you can help, backup link.

NeptuneNeptune's Disappearing Clouds Linked to the Solar Cycle, backup link.

Pluto None Of Pluto's Five Moons Actually Orbit The Dwarf Planet, backup link.

Haumea NASA Studies Origins of ‘Weird’ Solar System Object: Dwarf Planet Haumea, backup link.

Makemake - The Dwarf Planet Named for an Easter Island Fertility God, backup link.

Eris -  Meet the Solar System's five, backup link.

Quaoar - Dwarf planet Quaoar has a ring instead of a moon, and scientists don't know why, backup link.

Orcus The Dwarf Planet Orcus, backup link.

Salacia As big as Ceres, but much farther away, backup link.

Gonggong - First dwarf planet in solar system named after Chinese mythical figure, backup link.

Sedna 2029 will be the perfect year to launch a mission to Sedna, backup link.

Thursday, October 28, 2021

A wikipedia article all grown up: Brine Pools

I was watching some nature show back in the mid-aughts that covered the topic of the ocean floor.  This show mentioned the geological formation called brine pool.  Brine pools are amazing "lakes" of brine at the bottom of the ocean.  The water of a brine pool is separated from the ocean above due to the pool's extreme salinity.  Brine pools even have their own surface upon which objects can float.  Imagine this: a submarine floating on top of a brine pool at the bottom of the ocean.

So, why all this talk about brine pools now?  Well, at that time, I was interested to learn more about them.  Upon searching the topic on the Internet, I found nearly nothing.  Wikipedia didn't even have an article about brine pools.  That means it was up to me to create the article.  The only thing I had to go on was what I remembered from the nature show.  So, all I could say was this:

"Brine pools have been discovered at on the ocean floor near methane vents. Lifeforms around these pools do not depend on the sun for energy."

That's it.  That was the whole article.  It's dangerous (metaphorically) to add articles to Wikipedia.  Wikipedia is a vicious and uncaring environment with nearly draconian rules about what can stay and what must be removed.  It's doubly risky (again, metaphorically) to create an article with only one sentence for a topic that isn't well know.  The final risk is posting such an article without any citations.  

By some miracle, the brine pool Wikipedia article grew.  This happened due to other editors adding more detail and cited sources.  Images were added soon after.  I kept an eye on the article and helped edit it further from time to time until late 2010.  At that time, the article grew to include a couple of images and three subheadings, each with a short paragraph.  By the Wikipedia measure, it was "2,960 bytes".  


2010 is around the time I stopped editing on Wikipedia in general, but for no other reason than I just got too busy.  So, I forgot about this little article over time.  It wasn't forgotten by others, though.  The article had a moderate number of edits between 2010 and 2017.  Its size grew to a modest 3,410 bytes by the middle of 2018.  

In August of 2018, according to the article's history, something weird happened.  An anonymous editor added a new subheading with a rather large paragraph.  The problem with this edit was that the subject of the subheading had nothing to do with brine pools, but was actually about the land formation of artificial brine sinks.  The edit appears to have been made in good faith by someone who did not understand the topic of brine pools.  After some back-and-forth edits, the incorrect subheading was removed by other editors.  After that, edits to the article went quiet until September last year.

It appears that someone familiar with the topic of brine pools added a ton of detail in Fall of 2020.  Edits by others quickly followed.  The article ballooned to 10,269 bytes, then again to 21,471 bytes.  Over the past year, the article has received regular and quality edits.  It's turned into a good article about the subject.  The current version of the article is 28,184 bytes with five well flushed-out subheadings and tons of cited sources.  Of course, a lot new information has been discovered about brine pools in the past 15 years, which may have something to do with the explosion of information added to the article.  Most of the cited scientific studies were published since the inception of the brine pool article.

How did I suddenly remember this little article that could?  Literally yesterday, a related geological formation, called cold seep, showed up in a news feed.  Cold seeps are associated with one of the three methods that form brine pools.  So, I was reminded about the article I created all those years ago.  I checked out the brine pool article, and it is glorious (hyperbole, of course).  

I'm glad I was able to contribute in some small way to the dissemination of scientific knowledge.  I've created many other Wikipedia articles, but this one seems to be the most impactful.

One side note, I've actually referenced Wikipedia a lot over the years!  Check out this search: Wikipedia search.

Monday, January 30, 2017

Maybe we are the first

I've said several times that it is possible that the human species is the first species in the Milky Way galaxy to evolve to our level of intelligence and technology.  This opinion is based on information about just how much needs to happen to allow for the spark of life in conjunction with the apparent rarity of our own solar system.  The recent study Relative likelihood for life as a function of cosmic time seems to confirm this idea.

A basic premise is that life requires stars for two different purposes.  The study states,
Life requires stars for two reasons. Stars are needed to produce the heavy elements (carbon, oxygen and so on, up to iron) out of which rocky planets and the molecules of life are made. Stars also provide a heat source for powering the chemistry of life on the surface of their planets.[001]
This means that rogue planets aren't likely to spark or support life.  This also means that Population III and most Population II stars systems will not have life either, because they are unlikely to have the elements necessary to form terrestrial planets.  That pretty much leaves us with Population I stars.

Rogue Planet - artist concept
Rogue planet, artist concept
Population III or II stars, article concept
Population III or II stars, artist concept
What's all this about "Population"? It's a name for stars at various stages of galaxy development.  
  • Population III stars are the stars that likely formed right after the Big Bang.  They have not been directly observed, so their existed is estimated.  They were made up of mostly Hydrogen and Helium.  As such, they are unlikely to have any planets.
  • Population II stars are stars that are still made up of mostly Hydrogen and Helium, but have higher concentrations of elements such as Oxygen, Silicon, Neon, etc.  Typically, such star systems are still unlikely to contain terrestrial planets.  Many Population II stars still exist in our galaxy, though in regions without access to many heavier elements.
  • Population I stars are stars that are yet again still made up of mostly Hydrogen and Helium, but have much higher concentrations of the more stable element Iron and other heavy elements.  Population I star systems are much more likely to contain terrestrial planets.  The Sun (Sol) is a Population I star.
Why is this discussion about "Populations" important to the discussion about the arrival of human-like intelligence?  At the risk of oversimplifying this a bit, I'll state that Population III stars lead to the formation of Population II stars, and Population II stars lead to the formation of Population I stars.  As each generation of stars lived out their lifespans, they made way for the next generation to arise.  Population I stars could not have formed 13.5B years ago; there weren't enough heavy elements around.  Just as today, it is extremely unlikely that Population III stars could arise now; there's too much heavy elements around.

Life is very unlikely to have occurred until Population I stars formed and supported terrestrial planets.  Terrestrial planets in the Goldilocks Zone around their star then had to have the necessary events and composition to allow for the spark of life to occur, and subsequently support life until species of higher intelligence evolve.


Is Earth ahead of the curve for the development of life?

The previously mentioned study suggests that Earth may have developed life to the human-level a bit earlier than average.  The study concludes that, "life around low mass stars in the distant future is much more likely than terrestrial life around the Sun today."[001]  Life throughout the galaxy may be far more common billions of years from now than it is today.  That also means that there may not be any/many other alien species with which we can contact and interact right now.  The study puts our odds at 0.1%.[001]

This could explain why we've not seen evidence of extraterrestrial intelligent life in our galaxy.  Maybe we are among the very first. Others like us are so rare, we will not be able to contact each other.

Maybe a billion years from now, a future intelligent species will evolve on some future (yet to exist) world, and when they point radio telescopes into their  night sky, they receive a song of hundreds of thousands radio signals from just as many other civilizations.  Maybe, if our species is able to continue evolving, our long-from-now-posterity becomes the evil invaders of other worlds, rather than our world being the one constantly invaded, as Hollywood would have us imagine.  Maybe we are the monsters in waiting.

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Monday, January 23, 2017

"Goldilocks zone of metallicity" on a galactic scale

What does the night sky look like to a planet within the Galactic Bulge?  Cool Cosmos describes it as,
Stars in the Galactic Center are so concentrated that they typically are only a few light weeks away from each other. In contrast, our local neighborhood of stars are separated from one another by light years. If we found ourselves on a planet near the Galactic Center, our nighttime sky would light up in a blazing display every night, filled with stars as bright as the planet Venus looks to us.[001]
However, would there be a habitable planet from which to see this sight?  Is it possible to have life-supporting planets near the Galaxy's center?

The concept of Habitable Zones around stars has been studied for a couple of decades.  Life similar to ours can only exist on planets that are a certain distance from their sun.  This is due to the amount of energy from the sun that is received by the planet.  Too much energy, the planet is too hot.  Too little energy, the planet is too cold, hence the Goldilocks reference.

There's another type of Habitable Zone at the galactic scale which uses a somewhat different set of criteria.  Solar systems which have planets that can support life must themselves be made from material that has a lot of elements that are heavier than Helium.  In astronomy, elements heavier than Helium are often referred to as metals.  Metal content of a star is called its metallicity.  The danger is that is if a solar system is made from material that is too rich in metallicity, Earth-sized planets may not be able to exist due to the likelihood of much larger (heavier) worlds displacing those Earth-size planets.  Hence, "Goldilock zone of metallicity" is the idea that certain regions of a galaxy may be too metal-rich and other regions may be metal-poor in order to allow for the presence of Earth-like worlds.[002]

It's not just the metals

Metallicity is not the only factor, however.
Early intense star formation toward the inner Galaxy provided the heavy elements necessary for life, but the supernova frequency remained dangerously high there for several billion years.[002]
If a solar system is too close to the galactic core, the intense supernova frequency in a young galaxy might've keep many worlds from supporting life.  This is because they would have experienced numerous blast waves, cosmic rays, gamma rays and x-rays that are fatal to lifeforms.[002]  As the collective of solar systems age and die, they would have contributed to increasing metallicity.  This means, the right conditions for life on Earth-like planets may have never happened near the galactic core.  Stars that are too close to the galactic core never had and never will have the right conditions to support Earth-like worlds with Earth-like life.

Where can solar systems with habitable planets reside within the Milky Way?  According to the study The Galactic Habitable Zone and the Age Distribution of Complex Life in the Milky Way, the inner bulge component, diffuse halo component, and a thick disk component of our Milky Way Galaxy would not likely allow for Earth-size planets to exist within the right timeframe.[002]  So, the Habitable Zone of our Milky Way Galaxy isn't even really based on distance from the galactic core.  It's a somewhat washer-shape region in between all the places that Earth-sized planets cannot exist within solar systems.

Current Habitable Zone of Milky Way 

Given all of these factors, the authors of the study The Galactic Habitable Zone and the Age Distribution of Complex Life in the Milky Way state,
We identified the Galactic habitable zone (GHZ) as an annular region between 7 and 9 kiloparsecs from the Galactic center that widens with time and is composed of stars that formed between 8 and 4 billion years ago.[002]
Galactic layout © Matthew Lorono 2016

Knowing our Milky Way's Habitable Zone helps us in the search for life on other worlds.  We can focus more efforts on this space.  This isn't to say that this is the only space where life can and does reside.  The Galactic Habitable Zone is just our safest bet for finding evidence of life.

Primary reference:
C. H. Lineweaver,Y. Fenner, B. K. Gibson, Science 303:59–62, DOI: 10.1126/science.1092322, The galactic habitable zone and the age distribution of complex life in the Milky Way

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