A supernova releases as much energy in days as our Sun does in several billion years. In 2018, the Hubble Space Telescope observed a supernova 70 million light years away, which outshone its entire galaxy until it faded away over the following year.
This video zooms into the barred spiral galaxy NGC 2525, located 70 million light-years away in the southern constellation Puppis. As we approach an outer spiral arm a Hubble time-lapse video is inserted that shows the fading light of supernova 2018gv. Hubble didn’t record the initial blast in January 2018, but for nearly one year took consecutive photos, from 2018 to 2019, that have been assembled into a time-lapse sequence. At its peak, the exploding star was as bright as 5 billion Suns.
While nuclear fusion and a slow neutron capture process form all the elements up to 83 (Bismuth), the elements are also produced very rapidly in supernovae along with all the heavier elements. Supernovae have produced the the bulk of the universe’s precious metals, silver, platinum and gold, and are responsible for the creation of the heaviest elements up to uranium.
Supernovae like this all peak at the same brightness and so can be used to accurately measure the distance of their host galaxy, allowing accurate measurement of the universe’s expansion rate. The current best estimate is that the universe is expanding at a rate of 69.3 km/sec/Megaparsec plus or minus 0.8. That means that for every Megaparsec (about 3 million light years) that you go out, the Universe is expanding 69.3 km/sec faster. So that means that NGC 2525 is moving away from us at a speed of around 1500 km/s or half a light year each century.
In a previous post, I wrote about my great-great-great-grandfather, Thomas Wilson (who was transported to Australia as a convict in 1834). He had been sentenced to 7 years transportation for highway robbery. In researching his descendants, I documented a granddaughter Annie Priscilla Wilson, who was born in 1880 to his son Thomas Wilson (1847-1923) and wife Frances Oliver (1852-1893). Annie Priscilla married John Fitzgerald in Manly in 1900 and they moved to Wollongong. She died in 1964, I have seen the death certificate, and she is buried in the Wollongong Cemetery (Sect. RC Row: Nth 25 Site: 26). I have been contacted by one of her grand-daughters who has confirmed all these details.
This is where it gets interesting. In searching for information on Thomas Wilson and his family, who lived at Church Point, Pittwater north of Manly in Sydney, I came across a website with the following information. It described the rediscovery of the graveyard associated with the first St John’s Anglican Church in Mona Vale, about 5 km from Church Point, where the Wilson family lived. This church was a small weatherboard structure built in 1871 overlooking Mona Vale Beach, which was moved to a new site in Bayview in 1888. One of the gravestones uncovered was for “Annie Priscilla Wilson Aged 2 Years (1880-1882) Dearly loved daughter of Frances and Thomas Wilson”. I have also found a photograph of the Memorial Plaque erected on the site in her memory. There is only one birth “Annie Priscilla Wilson” registered in NSW for anyone with the names Annie, Ann, Anne, Priscilla and parents Thomas and Frances Wilson in the date range 1865-1900. So this is a complete mystery. Although her gravestone has been found saying she died in 1882, she also got married to John Fitzgerald in 1900. I also cannot find a death certificate for Annie Priscilla Wilson in 1882.
The human Y chromosome is a male-specific sex chromosome. When mutations (errors in the copying process) arise in the Y chromosome, they are passed down directly from father to son in a direct male line of descent and define a tree of Y “haplogroups”. The mutations on the Y chromosome can thus be used to trace our paternal ancestors all the way back to the most recent common paternal ancestor of all men alive today, Y chromosomal Adam.
When I first got interested in genetic genealogy around 2010, I had my DNA tested by the National Genographic Project, funded by the National Geographic to collect over a million DNA samples to map the patterns of human migration across the world. This project measured mutations known as short tandem repeats (STRs) at 12 sites, and gave a statistical prediction of my Y-haplogroup, R1b (M343) and subclade R-M269. A year later I upgraded my Y-DNA analysis to 44 STRs with Ancestry.com. At the time, I decided that I would wait for the technology to improve and the cost to drop and do a more comprehensive test which would definitively determine my Y haplogroup.
And so last year I did the Big Y-700 test with FamilyTreeDNA which examines 700 short tandem repeats, and over 200,000 single-nucleotide polymorphisms(SNPs) identifying known haplogroups as well as millions of locations where there may be new branch markers on the Y chromosome. This company claims to have the world’s largest genealogical YDNA database with over 2 million people included.
Y-chromosomal Adam is the name given to the patrilineal most recent common ancestor (MRCA) of modern humans. In other words, he was the man from whom all living humans today descend, on their father’s side, and through the fathers of those fathers and so on, back until all lines converge on one person. He is the male counterpart of Mitochondrial Eve, who,lived in north-western Botwsana around 177,000 years ago (confidence interval ± 11,300 years).
When I did my first Y-DNA test in 2012 with the National Geographic’s National Genographic Project, it gave a date of 60,000 years ago (60 kya) for Y-chromosomal Adam. This was already outdated, as other recent estimates around that time gave dates ranging from 120 to 160 kya. By definition, it is not necessary and highly unlikely that Y-chromosomal Adam and Mitochondrial Eve lived at the same time or in the same location.
However, in 2013 scientists announced the discovery of an extremely ancient Y DNA haplogroup from a sample submitted for an African-American man in the USA. Y-chromosomal haplogroups are defined by mutations in the non-recombing portions of DNA from the Y chromosome. These mutations accumulate at the rate of roughly two per generation. The accumulation of mutations in the descendants of Y-chromosomal Adam allow us to map out the major branches of the family tree in terms of Y-haplogroups. This discovery adds a completely new branch to the Y-DNA family tree and pushes back the age of Y-chromosomal Adam to around 250 to 300 kya.
This is the second part of a post summarizing current understanding of the evolution of humans. In the previous post, I outlined the evolution of pre-human species from the first monkeys around 35 million years ago (Mya) to the appearance of the first human species around 2 Mya. This post takes a look across the evolution of humans from the appearance of the first human species Homo habilis to the appearance of anatomically modern Homo sapiens sapiens around 250 thousand years ago. The following figure summarizes the evolution of humans over the last 2 million years, based on  with some modifications to take account of some recent discoveries.
The evolution of humans (the genus Homo) over the last 2 million years. Updated from Figure in Wikimedia. User:Conquistador, User:Dbachmann / CC BY-SA. (https://creativecommons.org/licenses/by-sa/4.0)- . The late survival of robust australopithecines (Paranthropus) alongside humans until about 1.2 Mya is indicated in purple. The rapid “Out of Africa” expansion of H. sapiens is indicated at the top of the diagram, with admixture indicated with Neanderthals, Denisovans, and unspecified archaic African hominins.
Our understanding of the evolution of us modern humans has changed dramatically in the last few years as ancient genomes are decoded and we discover that humans, Neanderthals and Denisovans interbred, and also in the remote past interbred with previously unknown “superarchaic” human groups. Scientists are also discovering new species of extinct hominids, and no doubt will continue to shed further light on our origins. Just to try to sort out the big picture in my own mind and to put these various discoveries in context, I’ve tried to summarize what we think we know, or at least what the evidence available to date suggests. This will no doubt continue to change.
This is the first of two posts and summarizes the evolution of pre-human species from the first monkeys around 35 million years ago (Mya) to the appearance of the first human species around 2 Mya. A following post will summarize the evolution of humans from the appearance of the first human species Homo habilis 2 Mya to the appearance of anatomically modern Homo sapiens sapiens around 250 thousand years ago and mitochondrial Eve, who lived around 178,000 years ago.
In an early post on this blog, I summarized my maternal-line ancestors and where and when they lived. In the last 6 years, there have been substantial revisions to estimates of the dates associated with these mitochondrial DNA (mtDNA) haplogroup founders, and revisions to the mtDNA haplogroup tree (deep-maternal-ancestry-and-mtdna) and this post provides an update. I am a member of mtDNA haplogroup U5, which is one of nine native European haplogroups stemming from haplogroup U which most likely arose in the Near East, and spread into Europe in a very early expansion. The presence of haplogroup U5 in Europe pre-dates the last ice age and the expansion of agriculture in Europe. Today, about 11% of modern Europeans are the direct maternal descendants of the founder U5 woman. They are particularly well represented in western Britain and Scandinavia. My more recent maternal ancestors were part of the population that tracked the retreat of ice sheets from Europe at the end of the last ice age and re-colonized Britain about 12,000 years ago.
The mtDNA sequence at the root of each haplogroup arose from one or more mutations in the mtDNA of just one woman, and the age of the associated haplogroup gives the time in the past when this specific woman lived. To emphasise that the maternal clan founders were real individuals, I have used the names given to them by Sykes  and Oppenheimer  and given my own names to the more recent subgroup founders. The Table below summarizes these founders, dates and locations and is followed by brief biographies. The haplogroups are identified by the labels used in Build 17 of the ISOGG mtDNA tree which can be accessed at http://phylotree.org/ . Dates in the table below have been updated using most recent available dating estimates as described in my previous post deep-maternal-ancestry-and-mtdna.
The migration path out of Africa into Europe of the “grandmothers” linking mitochondrial Eve through to Ursula (U5) is shown on a map in my previous post deep-maternal-ancestry-and-mtdna. The subsequent migration from Europe to Britain is shown in the map below.
Figure 1. Migration path of my maternal ancestors from Ursula (U5) to Viviane (410 CE). A map of the earlier migration from mitochondrial Eve to U5 is included in an earlier post.
Updated biographies of my maternal haplogroup great* grandmothers follow below.
In February 2014, I did a series of posts on my deep maternal ancestors, identified through a test of mutations on my mitochondrial DNA (mtDNA) which is inherited only from the mother. This test was carried out by Ancestry.com, who have since discontinued tests of mtDNA and Y-chromosome DNA. Costs of DNA tests have dropped dramatically since then, and late last year I ordered an mtDNA test from FamilyTreeDNA (www.familytreedna.com) which carried out a full sequencing of the mitochondrial DNA.
As well as the DNA that makes up the chromosomes in the nuclei of our cells, we also have another type of DNA called mitochondrial DNA (mtDNA). The mitochondria are organs located outside the cell nucleus which convert sugars into energy. Mitochondria have a small circular loop of DNA, containing only approximately 16,569 base pairs in humans. The circular mtDNA is similar to the DNA of bacteria, and it is thought that mitochondia evolved from symbiotic bacteria that were once free living.