The Big Splat or How Our Moon Came to Be

The Big Splat or How Our Moon Came to Be

This might be a series of reviews and overviews of science and skepticism books. Right now I am starting with books that I have handy to me so they will a bit outdated. Hopefully in October when the Skeptics Guide to the Universe podcast book comes out I will get as soon as possible and before that I will read A Demon Haunted World.

This overview is of The Big Splat or How Our Moon Came to Be by Dana MacKenzie in 2003. I have read this years ago while working at call center. This is basically a history of our views of what we thought of the moon over the last 2500 years. It starts in Greek times and finishes in the early 2000’s. The story does mention of the usual suspects in planetary science and astronomy such as Kepler, Galileo, Newton and Darwin (probably not the one you are thinking of.).

The first couple of chapters of the deals with how for until recently in human history how the moon was the only light at night and then how Greeks brought the moon back to Earth from the gods. The Greeks originally thought that all the celestial bodies were gods, the god of the Moon was Artemis. Then a meteorite came down to the Earth, this one was different then any previous meteorite. First it landed in Thrace, second people found it. It also fall when the Greeks the group that controlled this area started to try to explain things by natural reasons rather than supernatural reasoning. Anaxagoras one of the first physici, he eventually figure that the moon, the sun, stars and planets were made of solid matter. After this there were two different schools on what the heavens were made up of and the other still wanted to believe that heavens were made out of the same stuff as the Earth.

The next major set of developments came about almost two thousand years later. It started with Nicolas Copernicus who came up with the idea that the planets including the Earth orbited around the sun and not everything orbiting the Earth. The next development came bu Johannes Kepler. Kepler started hos career as a math instructor in a school. One day he had the thought the orbits could fitted by the platonic solids. He got the attention Tycho Brahe who was the astronomer to the Emperor of Austria
and Kepler his assistant. After Tycho passed Kepler inherited Tycho’s observational data including that of Mars. Kepler tried to fit the observations to an orbit of a circle but couldn’t find out how. He eventually considered the eclipse which is a slightly squashed orbit. He then realized that the a planet orbiting the sun would cover the same are over the same time. Another relationship he found was that the square of the time it took a planet to orbit a star was equal to the cube of the radius of the orbit. The major player was Galileo, he did not invent the telescope or the first to point at the moon or the havens.
But he was the first to realize that the objects moving around the planet Jupiter to be orbiting around Jupiter itself. Galileo wrote a 40 page pamphlet describing his discoveries and his telescope design. Kepler wrote a pamphlet in response in which he described a better arrangement of lenses to improve Galileo’s telescope. Kepler last major installment in the tale of the moon was a Sci-Fi story which he tells of a traveler to the moon and his meeting the inhabitants of the Moon. This actually got his mother in trouble because of the method he described tot he moon looked a like witch craft, eventually she got out of the charges.

The next major contribution was done by Issac Newton. He didn’t really make any great discoveries about the moon but how things orbit. When an object orbits another object there is force towards the object in the center, the force decreases by the square of distance between the two objects and the force is dependent on the force of the two objects. He also along with Leibniz of Germany the new branch of mathematics called calculus. Immanual Kant and Marquis Laplace thought the solar system formed by a spinning collapsing cloud of gas and dust, they came up with the theory independently within years of each other, knowledge took a lot longer to get around. They figured that the moon formed in a region near Earth in this theory This was the coaccretion process was refined. The major refinement was worked out Roche. Roche discovered if a moon comes to close to the planet it is orbiting the moon would break apart. The most famous example of this Saturn’s rings which are 2.46 the radius of Saturn. To do this to the moon it would be 2.49 the radius of Earth because our moon. He figured that the it was the sun’s tidal force and the not the force from the Earth had a greater effect on the forming Earth -moon system. His calculations showed the Earth had in influence on objects within 237 times its radius.

The next major theory came form George Darwin son of the one that wrote something about natural selection. George become of the great mathematician of his era and got intrigued by the tidal forces between the Earth and the moon. He realized that the interaction between the two was slowing down how fast the Earth was revolving around its axis and how long moon was taking to orbit the Earth so one day the two would be the same of 55 days. This also meant as you went back in time the Earth would be rotating once in 5 hour and 36 minutes. Darwin thought that at one point the was ejected from the Earth. At around the same time the discovery of radioactivity and and radioactive elements. It was discovered that Uranium decayed into lead at a certain rate and the age of the Earth was figured to be 4.47 billion years which was off because the decay process wasn’t fully understood at the time.

The next theory how the moon came to be was the capture theory. This theory was first brought about T.J.J See. See was from the southern states and named after two confederate generals. When went to Germany for graduate school and was told not to think about planetary formation because it was a dead end instead he went to study binary stars. He discovered over 400 pairs of stars orbiting each other. He was invented to work at the university of Chicago to help setup an astronomy department there. He convinced a business man by the name Yerkes to donate the money but because of politics at the university Hale was named his supervisor. Eventually he ended up working for the US Navy at mare Island as a time keeper for most of the west coast of the US. While there he had time to write articles for the local paper and came up with the idea that the moon was captured and Darwin’s and other math is wrong. He published his theory in the self published volume,Evolution of Solar Systems, vol II, The Capture Theory. He stayed his post until his death in 1962. Starting in the mid 1950’s a German high school teacher Gerstenkorn started to do calculations on the capture theory later MacDonald in England partnered with him to to do the model on computers. These models showed that the moon would have to come within the Roche limit a few days each orbit and it could survive without breaking up, the moon would of heated by 2000-5000k which would melt the surface of the moon and the would have been travelling +/- 5% the speed of the Earth at the time.

Around this time Otto Schmidt one of the heroes of the Soviet Union was allowed to open a research institute outside of Moscow. One the researchers was Safronov. Safronov Started to do his calculations on planetary development without computers. His calculations showed that a field about 250 time s the radius of the Earth surround the Earth until it formed the moon. The major contribution his model introduce was collisions between objects was possible this explained way Uranus rotates with one pole pointed to the Sun rather then pointing at a 90 degree angle.

The Americans and the Russians got into a race of who would do what first in Space and this led to the Americans putting 12 men on the moon in late 60’s and early 70’s, there was another mission that was suppose to go there but had some issues. While the astronauts were on the moon 841 lbs of samples were returned to the Earth from different locations on the Moon. These samples showed the mare or seas were made up from magma flows and 3.6 billions years old and regolith which is 4.5 billion years old and thicker near the highlands at 10-15 meters and about 5 meters in the mare. Regolith was formed from meteorites colliding with the moon. They found that 98% of the moon was composed of 4 minerals, plagioclase feldspar (CaAlSi₂O₈), Olivine( (Mg,Fe)₂SiO₄. Pryoxene (FeSiO₄ or CaSi₄O₆), and Ilmenite (FeTiO₃). Before the astronauts could go they needed to know where to land. In 1963 William Hartmann went to the University of Arizona to study at the Lunar and Planetary Laboratory under Gerard Kuiper. One of Hartmanns first jobs was to take photos taken of the moon and to transfer them to a globe. While doing this they figured Mare Orientale was formed by a 90 km asteroid hitting the moon. Hartmann’s next job was too count the moon was to count the amount of craters in certain areas to find an estimate of the age of moon, the more craters the more time it had a chance to get hit by the asteroids. He came to the idea that the mares were about 3.6 billion years old before the astronauts went to the moon. When moon exploration was winding down Hartmann and Davis worked on refining Safronov’s model. Their model showed a lager body that started to form around the Earth this object later got the name Thea. It took some time but it eventually became to be the concensus of how the moon was formed.

Our current understanding of how the moon was formed started when the solar system was formed. A cloud of material started to form where the Earth-moon system is now. When the Earth got to be about 90 percent the size its present size Thea collided with the Earth, the Earth got most of the iron out of the two. For the next 50 million years the debris from the collision of two are finished forming the two present day objects. Four hundred million years later a bombardment of materials hits the Earth and moon for about two hundred million years. Two million years later the radioactive elements of uranium and thorium melt areas where the mares are today and eventually cool off. Since about 3.2 billion years ago the moon settled down pretty much with the impact here and there.

The book is a good read and is good at explaining things and I enjoyed every time I read it. I once did attend a talk Given by Eugene Shoemaker. It was given in my first year of university and I was 1 in hundreds in the theater (it was a room used for a lot of first year university talks ). In the last section the author discusses the moon hoax theory that no one has been to the moon. The evidence does not support such claims. Because I did not far so well at university I tried to get out of my system it didn’t really work and started to read astronomy magazines then started to follow Phil Plait who is the reference part of this book. His first book was on the arguments of the hoax believers and the reasons they are wrong, so there was some influence of this story on even my life. If you have a chance to read this book , pick it up and read it you might become a lunatic. [/p]

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Some Reasons why intelligent Design is Not Science.

In the morning the first thing I do is get the newest episodes I listen to, and sometimes check youtube for new videos, plus this morning I was waiting for a friend to post his most recent video about his car dealership. I mostly watch stuff on star trek, star wars, history and a few other topics. This morning I was saw a video about the history of the Celts. This peaked my interest because I have some Celtic in me (English, Irish and Scots) so I watched the video then saw another video about “Why Intelligent Design is not Science” this peaked my interest again and watched it, there goes the morning.

Intelligent design was brought about in the United States to do an end run around the first amendment in the Constitution which separates church from state. It was already determined that creation teachings were not allowed in the science classroom because it was not science. So a new tact was taken and that was a re-branding creationism as intelligent design. This was brought to a head in court case in Dover PA in the 2000’s. Some members of the school board arranged for an additional textbook called the “ The Pandas Thumb.” In the rush to publish the text book creationists was changed to “cdesign proponentist” and the judge saw this as an attempt to sneak creationism into the science classroom. I not hear to criticize peoples beliefs or thoughts everyone is entitled to their views and to make carpet statements would be unfair.

The first two examples they use is SETI and archaeology. SETI or the Search for Extraterrestrial Intelligence is the search for life other than our own in the universe. The intelligence that they are searching for beings like ourselves. This is done by looking for planets around other stars and looking for the tell tale traces of life from the spectrum of the light from the planets, or detecting any radio transmissions that these civilizations might be emitting. Archaeology is the study of ancient man, this is done by the study the bones and artifacts left by ancient man. Most of the ancient tools were stone tools and archaeologists study to know the difference between regular stones and the ones worked by the hands of man. Another example this video uses is that of Stonehenge. Stonehenge is a group of stones arranged in a circular pattern in Wiltshire, England. The stones were moved there, dressed and stood up by human hands. They stones can be determined if they were there naturally or moved there by their chemical make-up. The main difference between this type of intelligence and the one behind intelligent design is that of natural vs. supernatural. The natural intelligences have an influence of the natural world and can be measured and they supernatural intelligence can not be measured and outside the realm of science.

The next two examples they use are string theory and multiverse theory. Both are theoretical constructs to explain some things in physics. String theory basically is that all subatomic particle vibrate like strings and if change the vibration of a string you can change what type of particle it is like an electron can be turned into proton. String theory at this point can be tested because the energies involved to test it. The multiverse theory is that there are multiple universe existing and this can not be tested because there is no way of travelling between universes at this time. The major difference again is that their theory depends on something that can not be tested now or ever.

The next examples is that what I like to call scientist are just people after all. One claim they have is that Brian Green, Richard Dawkins and Neil Degrasse Tyson have stated that the universe is a computer simulation. This is probably them wondering why the universe is so set up for life like ours in the universe, this is often to referred to as the anthropocentric principle. If gravity was stringer the universe would be a giant ball of matter or if gravity was weaker everything would just be a fine mist in the universe. Or if the attraction between the the electron and proton were less atoms would be much larger. There is no evidence of it being a computer simulation so at the moment a lot of people are saying not. Another example they use is Francis Crick who co-discovered the structure of DNA in the 40’s. He thought that the life here came from somewhere else, this is called panspermia. He also thought aliens brought life here, and since this is untestable and there is more evidence life came form here this is probably not the case. Scientist are people too so they can weird and scientific thoughts as well.
A couple of last notes since intelligent design is not testable it is unlikely to be correct and is not scientific. The friends video I was waiting for is a creationists. During grades 7 to 11 I had a friend who I use to discuss this stuff with all the time.

Yes Flat Earth, Again.

http://ohnopodcast.com/investigations/2018/7/20/ross-and-carrie-traverse-flat-earth-part-7-the-jeran-campanella-interview

In this interview Ross and Carrie interviews Jeran Campanella a flat-earther, One thing he goes on about is how scientist are taught to believe that things are round. Scientist are not taught to think that things like the Earth are round but are taught how to observe and measure things then to come to conclusion. Scientist are taught that most likely the answer the more probably that is the right answer. One area of astronomy that demonstrates this is the history of Exo-planets.

 

 

As far back as the Greeks people noticed that the ships sails would slowly go down below the horizon. Also many notice during a lunar eclipse the shadow across the moon had a curved edge from where ever you observed it from. Also Eratosthenes (276BC-195BC) using a sticks shadow at two points, one in Alexandria and the other at Aswan both in Egypt and found the size of the Earth. The experiment that is discussed in the podcast is a variation on the sails going down in the distance.

 

 

Early in the twentieth century Peter Van de Kamp of Swarthmore University thought he found a planet, then another planet and then a whole system around Barnards Star. Barnards Star is unique in that is has the highest proper motion for any star. Proper speed is the component of speed that is independent of the motion of a star going around the center of a galaxy. Van de Kamp thaought he saw the path of the star to wobble as it was going thru the galaxy. Latter it was found to be there was a fault in the plates that the images were taken on. Astronomers used to use glass plates to develop the image of a star, now it is a CCD chip. Another story of planets that weren’t was in the ’90’s. A pulsar astronomer thought there was a wobble in the signal from a pulsar, a pulsar is a neutron star that emits a beam of radio waves at a steady pattern. The pulsar would have a change that would indicate something orbiting about once a year. When the astronomer was about to announce to the would of this object around a pulsar he realized that he didn’t get take into account the Earths orbit. He got up to the podium and announced his mistake and got cheers.

 

 

Admiral There be Whales

(The future website the pictures will be done a little better)

First thing of course something from Star Trek IV: The Voyage Home, the one with the whales.

First thing we travelled down from St Stephen to St Andrews NB down the route 127. On the way down it was so foggy that you couldn’t see the top of Chamcook Mountain or the St. Croix Island (a failed french colony in 1603). Once we got down to St Andrews and got a parking spot. St Andrews is a town that depends heavily of tourist activities so it can busy place on the weekend. There are several whale watching tours in the area, one is on a sailing vessel, a couple use zodiac type of boats and the other two are boats that have an enclosed lower deck and an upper deck. The one we went on had an open upper deck. We went on this tour because well my sister and brother in law(BIL) were working for them. The route for the tour went out around Deer Island and then between Deer Island and Campobello island. For the the first part of the tour I went to the upper deck.

 

 

Some salmon cages, leaving St Andrews, and a fishing weir. pic.twitter.com/vLoOHkSdBQ

— BackroadAstro (@BackroadAstro) July 29, 2018

Some salmon cages, leaving St Andrews, and a fishing weir. pic.twitter.com/vLoOHkSdBQ

— BackroadAstro (@BackroadAstro) July 29, 2018

 

 

One the out around the first island we saw a bald eagle right before we came to salmon cages. Another industry in the area is aquaculture with cages throughout the Bay of Fundy and Passamaquoddy Bay and my sister and BIL work during the week for of the companies that do this. One the way to the area we would find the whales we saw a few porpoises behind the boat. As we got closer to where it opened to the Bay of Fundy we started to see whales first was minke whale, minkes are smaller then the other whale we saw which was the Humpback whale. Minkes grow from are usually 6-8 meters long and sometimes to about 10m also the can be as massive as 4-4.5 tons. Minkes when the dive just show their dorsal side and do not show there tails. The way to identify them is markings on the their dorsal tail. The one we saw on this day was one called slice because most of the tail was sliced off or did not develop in the first place. After a few sightings of slice we moved on to where the other boats were. Then we saw the first sighting of V the humpback whale. It made a couple of arcs above the water and then made his terminal dive for several minutes. On his way down he showed his tail and this how you identify the whale. V has a notch out of his tail so this how it gots it name. Humpbacks are longer and get up to 12 meters long and much more massive. Then someone notice V over by the cliffs on Campobello Island and few blows out of the blowhole. Then I went downstairs because my seasickness kicked in. Then V showed up one more time between us and another boat maybe 100-130 m apart, and made another terminal dive.

 

 

https://twitter.com/BackroadAstro/status/1023321917275684866

After this we went out to a couple of islands as the BIL said they were running out of names for the islands so one that was covered with spruce trees was called spruce island and the other sandy island. Then we went to a fishing weir which is an old style of fishing herring. The herring go into a chute and goes into the weir and swim around in the weir until there are enough fish. In the past they call a local company to come in and suck them up to made into sardines and other snacks. Now the herring caught this way are used for bait for lobster fishing. Also on spruce island there was another bold eagle (I swear the BIL and the eagle have the same eyesight), Then we went around Deer Island, we encountered the ferry to the island. We travelled beside it for a while then went behind passed over it wake and passed the ferry. As we were approaching St. Andrews some smoked salmon pate was served I declined because my stomach was doing flip flops, then some ice tea which helped. Then on wards back to the dock.

 

 

https://twitter.com/BackroadAstro/status/1023355002029568005

 

 

This is one 3 hour tour that you will enjoy. A few side notes there is a tidal bore which is the second biggest whirlpool but only really appears during flood tides and we were going out just after high tide, so if you want to see that find out the tide schedule. Also a pair of binoculars would be good plus if you are going to invest in a new camera, get before you go out. Also if you need to take some motion sickness medicine before hand, also hold off on the upper deck until when you start to see whales.

 

Keep Looking Up

 

The biggest influence on my life would of be my grandfather. When I was about 3 my mother, my sister and me moved in with my grandparents. He was a school bus driver, who was a mechanic, had a large garden and who had land which was mostly woodland and he enjoyed being down in the woods. My grandfather like watching PBS at night because there wasn’t as much fighting on their shows compared the other networks. He mostly like nature and science shows also some of the dramas, mysteries and comedies. I probably saw Carl Sagan but I was too young to really remember and he influenced me later in life. But most of young life was helping my grandfather working on engines mostly getting the tools he needed, helping in the garden, or in the woods with while he was getting firewood. I did have some friends growing up as well. I was sick a lot as kid because until I was 1 o years old I did not know I had asthma, so I spent a lot of time inside reading and watching TV. Later on when I was 16 gramp wanted to build a log cabin on separate lot a few kilometers from the farmhouse. While out there we had a multiband radio that could pick up some local tv stations. Also while out there I started to read more. One thing we heard a lot about was the Perseid meteor shower. One night we went back to the farmhouse which had a couple of fields around it and saw the meteors streaking thru the sky.

The next school year on class I had was biology. During one biology class the teacher showed a clip form the series Cosmos made by Carl Sagan about 20 years earlier. Another video was 2001: A Space Odyssey, I actually talked the principal into letting take betmax machine home to make a coppy to VHS for to view, for study material. Over the years I found I few of Sagans books first was a copy of Contact, the version after his death, Cosmos a paperback text version of the tv series and eventually stuff like A Demon Haunted World. One of the websites that started to follow was Phil Plaits bad astronomy which eventually got to try to make own site. He is one of the people who continue Sagan’s
work of continuing science outreach using logic also he is bi geek like myself. On his blog I often would take on the Electric Universe or Plasma Universe supporters. The original version of this website was geared towards that subject matter has changed over time.

One PBS late at night there was series for about 40 called the “The Star Hustler”. It was hosted by Jack Horkheimer from Miami Planetarium. Each show was about 5 minutes long and talked about what would come up in the nights sky at night. Late at night I would probably be the only one up watching TV and see these bits. And at the end of every episode he would say, “Keep looking up.”

There have been many influences in my life and probably hopefully a few more.

There probably won’t be any more posts here anymore

There probably wont be any post here anymore because of several reasons. One of which I am designing a new one which have essays, stories, some videos I like and some pictures I have taken. Another reason in the past I have dealt with depression and combination of probably some sort of social anxiety. I am well out the depression but there are still issues that roam around the mind and until I get cleared up, it kinds of interferes with me reading, processing and writing. It might be tomorrow I month from new or never hopefully soon
Here are a few movies and screen shots of the website. Posted on my twitter account.

another page with video. pic.twitter.com/iX2aYGHRXK

— BackroadAstro (@BackroadAstro) July 16, 2018

a page with video inserted pic.twitter.com/yZn9zkkovW

— BackroadAstro (@BackroadAstro) July 16, 2018

getting closer to done but keep finding things to change and add pic.twitter.com/MMGAVz2S1F

— BackroadAstro (@BackroadAstro) July 16, 2018

Does Fermi Paradox really hold up

A famous scientists Enrico Fermi had a thought, if there is life in the universe why haven’t they contacted us by now. A lot of people thought this meant of course that there was no life in the universe.
This was idea came about the same time we were just learning about DNA and how it passes information from one generation to another. This was before extremophiles were found on the bottom of the oceans, Later the Frank Drake came up with a formula to express what is needed for people to figure out whether or not there is life in the universe.
The Drake equation starts with stuff like what we have a fairly good idea of such as how many stars in the galaxy, this has increased because the average size of a star has decreased therefore given higher number of stars. The number of stars that are formed each year. To things we a less accurate idea of such as how many stars have planets and how many planets around each star. Then to things we have no real evidence for such as how many planets have life, how many of those have intelligent life and how many have survived, The Drake equation can have many different results because we have no real evidence either way on these terms. And there could be other factors that may have an effect on whether or not aliens have contacted us. Maybe they have no interest in contacting others or we have not gotten to a certain amount of development to warrant contact. Maybe the haven’t gotten to a level of development to contact us, not everyone experiences progress at the same rate. Some ancient civilizations could of been around during an ice age and decided just to move on. It could we are in a civilization desert and in another part of the galaxy there could be a lot more.
We are finding planets around a lot of stars around stars that thought would not find them. Some of them a lot closer to the star then we thought the would. What astronomers are looking for are planets in what is called the habitable zone which is an area where water can exists in gas, liquid and solid. But in our own solar system people are thinking there could be life under the ice of some of the giant moons around Saturn and Jupiter. Plus some the gas giants around other stars might have large moons themselves where life could exist. Plus there are planets that belong to no solar system that could have any icy crust and oceans underneath where life could exist, So until all the planets and moons in the universe is tested, I will always have life that there life in the universe.

The Ongoing Story of Trying to Find Life on Mars.

 

Every since Giovanni Schaipelli found what he called channels and later mistranslated into canals on the surface of Mars people have been looking for life, intelligent or microscopic every since. Percival Lowell a wealthy businessman from Lowell, Massachusetts was so taking by this idea that he built an observatory in Arizona, later this observatory was used to find Pluto in the outer regions of the solar system. In the 70’s there was Viking that test the soil for evidence of life that turned up nothing. In 1984 the was a meteorite found in the Allen Hills it left Mars billions of years ago. It was tested in the 90’s for evidence for life on the inside of it and in 1998 was announced that there was there were fossils of bacteria inside of it but there has been doubt of it. In the 2000’s two rovers landed on Mars called Spirit and Opportunity land one the red planet and Opportunity is still in operation, These two found evidence of water, these were chemicals that could only exist or be formed in the presence of water such as “blueberries” which is a special kind of hematite a compound of iron found different locations. There was also the Phoenix lander that discovered chemicals called perchlorates that react with organic molecules and thought to have been evidence of life on the red planet. Satellites orbiting the planet have many geological features that might indicate there was or water on the planet.

Today it was announced that the Curiosity rover the newest rover on the planet, it has been there since 2012 found organic chemicals. These chemicals include molecules such as benzene and toluene and smaller molecules such as propane and butene. There were other organic molecules detected that had sulfur and chlorine but could be determined exactly what they were because the detector was not set up for such large molecules.

What does mean, well nothing for sure. There can be life on the planet now but we still need more evidence. Life need water and ther not much of it on the planet at the moment so it is more likely that there was life on Mars in the past when there was water. One thing that might indicate is the presence of methane in the atmosphere which is produce by living things. There could have been life in the past but again need more evidence. If life arose early in martian history it means that life does take long to start and if that is the case life might not rare in the solar system or in the universe as a whole. These a great pieces of evidence but we need more evidence before we know for sure if there is life out there.

Review of Mathew Anderson’s Habitable exoplanets: Red Dwarfs like TRAPPIST-1

Review of Mathew Anderson’s Habitable exoplanets: Red Dwarfs like TRAPPIST-1

Last Wednesday night while watching the Weekly Space Hangout on youtube live there was an offer if interested you can get an e-book copy of the book written by Mathew Anderson. So I wrote the e-mail and got a copy of the book last night (Sunday).

The book is only 66 pages but it is crammed with a lot of facts and theories about these stars and how people thinks comes about on these planets. The book does discuss that red dwarf stars do emit a lot of solar flares. Also they emit ultraviolet radiation but instead of the penetrating UVB and UVC the mostly emit UVA radiation so the radiation would probably would not do as much damage to DNA in cells in already existing life, Also it is discussed how this might not be helpful for evolving life because they would not be as many mutations. The composition of the atmosphere in touched such as the green house effect and how planets can lose atmosphere and how geological processes can recycle carbon dioxide and other gases. The TRAPPIST-1 planets have been found to less dense then the Earth, so there should be a lot of water which might hinder the development of life, I wish the author discussed brown dwarfs and the planets around them or the moons around the planets in theses systems and the chances of life on them. The book is worth read and the 1 or 2 hours it probably will take read it.

Planets Forming Around Forming Stars

http://adsabs.harvard.edu/abs/2018AJ….155…54W?utm_source=dlvr.it&utm_medium=twitter

This survey was done by ALMA telescope (Altacama Large Millimetre Array) in Chile It observes a star forming region in the constellation of Taurus 140 pc (430ly) away and is one of the closest star forming regions. The observations were done 24 stars in the m4-m7,75 spectral classes, 2 stars had there disks transiting or edge to Earth. These stars were mostly what referred to red dwarf class, small cool stars and some were brown dwarfs which are considered somewhere between a star and a planet.

The star forming region is a molecular cloud. It is called this because it is so dense that the ionization UV radiation does not penetrate the cloud and molecules of H₂ still exist in and are not broken apart by the UV radiation. The problem with this is that H₂ is hard to detect because it does not emit much. Usually tracer molecules are used such as CH, OH, CS and C₂H₂ These clouds tend be around 50 pc or. 163 ly across wit a temperature around 20 k with a density of 200-300 particles per square cm and have a mass 10 ⁶ the mass of the sun.

The survey measured objects that are forming in this molecular cloud. This is useful because it helps us understand how stars and planets are formed. If you can see a star when the dust is just collapsing, then another further along when the disk is formed and later when the first planets are show up you can make theories and models showing all the stages of how such a system forms. These stars are have a disk rotating around a central star or are binaries. There 3 binaries known in the group and 2 now a suspect to be binary stars after this survey. Most of the stars in the survey were 1-2 million years old with a couple that might be 20 million years old, these stars burn for about trillion years so this not much of a difference, The disk tend to have 0.2% to 0.6% of that of the parent object and had a radius of 20 to 40 AU for the smaller disks to 100 AU for the larger disks.