Month: June 2023

If you’re an evil genius supervillain looking to strike terror into your enemy with a big messy space cablooie, here’s a novel way to do it. Smash up some remnants of old stars right in front of your nemesis. The result will be a delightfully large, bright explosion, as well as an additional gamma-ray burst visible across the Universe. And it will scare everyone to commit your evil intentions.

To do this, of course, one must have extremely strange powers. These don’t exist outside of comics. But in the real universe there are ways to do this. You just need these massive stellar objects crammed together in space. Then they get a little too close and – it’s their fault! a massive explosion visible billions of light-years away.

GRB 191019A: the Star Destroyer

On October 19, 2019, astronomers focused on the source of one such event called GRB 191019A. The first clue was a long-term gamma-ray burst (GRB) that lasted about a minute. (That’s long in the GRB range, although there is evidence that some last much longer. However, most are only a few seconds to a few microseconds long.) Neil Gehrel’s Swift Observatory spotted it immediately. Months later, astronomers observed the fading afterglow from the GRB source. They used the International Gemini Observatory, as well as the Nordic Optical Telescope and the Hubble Space Telescope. The observations revealed stellar death in the crowded heart of a galaxy some 3 billion light-years away.

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Artist’s rendering of the SWIFT satellite capturing a gamma-ray burst. Photo credit: NASA

Observers described it as an almost demolishing derby-like collision of stellar debris and stars in the chaotic neighborhood of the galaxy’s central supermassive black hole. The source of the GRB flash was just 100 light-years from the heart of the galaxy. It turned out to be in close proximity to the central supermassive black hole. “These new results show that stars can die in some of the densest regions of the Universe where they can be collided,” said Andrew Levan, lead author of a paper on the GRB and its source. “It’s exciting for understanding how stars die and for answering other questions, like what unexpected sources could produce gravitational waves that we might detect on Earth.”

Search for Star Destroyers in unusual locations

What is unusual about this event, according to Levan, is that it took place in a very old galaxy. “Our follow-up observation showed us that the outburst was not a collapsing massive star, but most likely the merger of two compact objects,” Levan said. “By pinpointing its location at the center of a previously identified ancient galaxy, we had the first compelling evidence of a new path in which stars face their demise.”

Diagram showing the evolution of stars under most circumstances. GRB 191019A reveals another way of destroying stars or stellar remnants. Photo credit: NASA

In an aging galaxy one does not necessarily expect fireworks of this magnitude. This is because the prime time of star formation is long past. Most giant stars have already died as supernovae. However, its core could be a perfect place for the destruction of stellar debris in collisions. The central regions of many old galaxies harbor large stellar populations. By some estimates, more than a million people crammed into a region just a few light-years across. There are also clouds of gas and dust, as well as a population of stellar debris – the black holes and neutron stars that result from the deaths of massive stars.

All of these objects swarm around the central supermassive black hole. It wouldn’t take much to bring two stellar objects (be they nearby stars or remnants) together under the gravitational influence of the central black hole. For a second, two objects spin around each other; Next time, they collide and create a violent burst, which we consider a long-lasting GRB. There is also a burst of a gravitational wave followed by a flash of light.

Looking for more GRBs

Astronomers haven’t seen many of these protracted collisional GRBs in normal galaxies, but they’re probably more common than anyone thought. The galactic cores in which they occur are often obscured by clouds of gas and dust that obscure the initial GRB flash and subsequent afterglow. Luckily, GRB 191019A happened more or less “in the clear,” giving observers a chance to watch it for quite some time.

GRB 191019A is the first observed event to involve stellar remnants in a crowded galaxy core environment. Levan and others would like to find more of these now that they know what to look for. Their hope is to compare a GRB detection with a corresponding gravitational-wave detection, which would reveal more about their true nature and confirm their origins in even the direst of environments.

Ruby Observatory at dusk in May 2022. This observatory will be incredibly useful for studying the afterglow of GRBs from massive star deaths as well as from collisions in distant galaxies. Credit: Ruby Obs/NSF/AURA

Fortunately, the current observatories, along with future facilities like the Vera C. Rubin Observatory, can play a role. “Studying gamma-ray bursts like these is a great example of how the field is really advancing through the collaboration of many institutions, from discovering the GRB to discovering afterglows and distances with telescopes like Gemini to analyzing events in detail with observations across the electromagnetic spectrum,” Levan said.

For more informations

Unprecedented opportunity to destroy a star
A long-term gamma-ray burst of dynamic origin from the core of an ancient galaxy (ArXiv PDF)

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From Jennifer Marohasy’s blog

Jennifer Marohasy

I don’t think he was ever there – not once. But he has an opinion about the Great Barrier Reef. When I last checked, more than 111,000 of his followers (after just hours after it was posted) roared back the nonsensical message that the Great Barrier Reef is of course overcrowded and of course Peter Ridd is an underling of the sugar cane farmers – and the big tobacco companies too. Following this short YouTube channel are hundreds of congratulatory comments which confirm what I already knew that most of us here in Australia have become useful idiots. In political jargon, the term “useful idiot” refers to a person who supposedly advocates for a cause—especially a bad cause.

Too many Australians, young and old, voting Labour, Green, Liberal or Blue-Green largely give up their ability to reason in order to behave in fashion. It doesn’t have to be like this. It could be different, especially if the Jordan Shanks among us would first take some time to fact-check. Nobody does that anymore.

I emailed Jordan Shanks the following short message yesterday.

friendlyjordies@protonmail.com
Dear kind Jordie,

I just watched your episode on the Riddler and the Reef. I was hoping to see you in the water with some coral.

[I should have written with some sharks.]

How about you come over with me? We could visit the epicenter of the recent massive coral bleaching event, John Brewer Reef. We could go snorkeling over the reef crest together. You can see for yourself what condition it is in.

Graham Readfearn reported in the Guardian that it was the worst of the worst bleaching and then there were the official aerial photographs also reporting the bleaching. Last year even the UNESCO members of the United Nations visited – but not the John Brewer Reef. They said it was all dead and dying.

This map was promoted through March and April 2022 as it shows the Great Barrier Reef suffering from massive coral bleaching with the impression that most of the coral was dying.

But guess what: the assessment team never visited any of the reefs reported as bleached/dead and dying. The experts based their reports on the bleaching on flybys, which assess the condition of the corals from a plane window 150 meters up.

I tried that. You can’t see much. To learn the condition of the corals, you need to get in and under the water. Come and see it with me.

I’ve been underwater with John Brewer a few times and even filmed a short underwater documentary showing the corals up close.

You can watch the film here, https://vimeo.com/775205373

But of course it’s never the same as seeing it with your own eyes.

Corals at John Brewer Reef were filmed underwater and by drone at 5, 10, 20, 40 and 120 meters in early April 2022 – when this reef was reported as the epicenter of the sixth massive coral bleaching event. Contrary to media headlines, John Brewer Reef had good coral cover and the corals were colorful and healthy.

Kind Jordie, if you come over with me I can also show you the remains of the coral that was intentionally destroyed – by the fish. The hungry fish that eat the best coral.

You probably didn’t know that a humphead parrotfish eats about six tons of coral a year. Out on John Brewer Reef, they prefer the corals that have been replanted with all the government money. These fish cost Australian taxpayers hundreds of millions of dollars each year by eating the coral that you and I paid to replant. All of this certainly has another and bigger story.

You mentioned the old corals, the 500 year old corals, in your Riddler Ridd episode.

It was during lockdown in November 2020 that my dear friend, the late Rob McCulloch, called me and cried into his beer. He was devastated when he had to pay for a charter he secured for marlin fishermen and ET (Andrew Ettingshause) who has this TV show. However, due to the lockdowns, ET was unable to get across the border into Queensland.

I instead suggested that Rob take me for a week in search of Porites — those 500-year-old corals that are reported to be all dead because the reef is overcrowded. You know the story, the popular tale.

To be clear, the porites are massive, ancient, sturdier corals, some the size of minibuses, with growth rings that resemble tree rings, faithfully recording the ocean’s climate history.

Well, they used to do it before. How the story goes.

I wanted to go as far as Myrmidon Reef, because that’s where scientists used to go in really big ships to gut the really, really old Porites.

We were there for a week. Dennis, Wizzy, Shaun, Stuart, me and the skipper – Rob. [You can see us here, on the back of the Marlin fishing boat, Kiama.]

I am thankful for this experience. The adventure was funded by the B.Macfie Family Foundation through the Institute of Public Affairs after I called John Roskam. He took a risk and believed in me when I said this was the chance of a lifetime.

I made a film about this adventure and it even includes Riddle’s Ridd – as you call him.

You can watch Finding Porites here: https://vimeo.com/766755037

Under water we found a whole garden of Porites. It was the white tip reef shark that showed us the way. Finally.

Visit us here in Queensland on the Great Barrier Reef and see some coral and coral eating fish. I’ve been trying for a number of years to get the experts at the Australian Institute of Marine Science to sit down in front of a camera and answer a few questions about the flybys and the bleaching. I’ve always wanted to ask them how they reconcile the extraordinary beauty and resilience of John Brewer Reef with their nonsensical maps – with no evidence or even photos. How they reconcile their claims of mass coral bleaching with all the colorful fish and coral I can see underwater.

Maybe if you, Jordan Shanks, come, they will come, and we can all go. Together. Even with Riddle’s Ridd. To John Brewer Reef, the epicenter of the recent much publicized sixth mass coral bleaching event.

We could maybe fly by and then go underwater the next day or at least snorkel over the reef crest.

Cheers, friendly Jennie

Doctors Jennifer Marohasy (aka Friendly Jennie) and Peter Ridd (aka The Riddler) walked across a mudflat south of the town of Bowen. On the other side of the mud flats you will find beautiful corals, at low tide you don’t even have to get in the water. Come and see.

***
The main image is by Toby and shows a school of Humphead Parrotfish. These are coral fish; each humphead eating around 6 tonnes of coral each year – a school of them (usually hanging around in groups of 30) eats about as much coral as all the coral planted each year at great expense to Australian taxpayers.

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Related

It’s a strange, spooky looking place. Carbon dioxide gas arises and disappears in cycles and bursts throughout the year. This is what our planet would look like if we could see carbon dioxide (CO2) with our eyes. Scientists at NASA’s Global Modeling and Assimilation Office created computer animations of its presence in our atmosphere. These videos show an almost alien view of Earth under the influence of this gas.

The NASA team created three animations, all showing carbon dioxide levels throughout 2021. Each shows four main polluters: fossil fuels, burning biomass, terrestrial ecosystems and the oceans. In the view showing North and South America, we can see how plants absorb the gas through photosynthesis and then release it again during the winter months. There are strong contributions along the US northeast coast, mainly from emissions from fossil fuel burning. There is also a rise and fall in gas over the Amazon rainforest. The team also interprets this to mean that plants take up carbon during the day and release it again at night.

Carbon dioxide measurements over North and South America in 2021. NASA’s Scientific Visualization Studio

The animations also show sources and sinks (where CO2 is absorbed) in Asia and show an incredible amount of fossil fuel emissions over China. In other parts of the world, such as Australia, absorption of this gas is much higher, with lower emissions due to smaller populations.

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Carbon dioxide measurements over Asia and Australia in 2021. This is a still from video created by NASA’s Science Visualization Studio.

A third view shows the contribution of fossil fuel emissions in Europe and crop fires in Africa. Overall, the videos provide a very clear overview of the presence of this greenhouse gas and its cycle in our atmosphere. (You can watch more videos here.)

This is a still from a video showing the carbon cycle cycle over Africa in 2021. Courtesy of NASA’s Scientific Visualization Studio.

Earth is not the only terrestrial planet that has this gas in its atmosphere. We know it’s in the atmosphere of Mars and Venus. And just recently, the JWST reported finding traces of this gas on an exoplanet. So it clearly plays a role in the planetary atmosphere.

carbon dioxide sources

CO2 is an important part of the climate cycles of our world. Sunlight floods the earth and carbon dioxide helps capture it and keep the planet habitable. Without this ability to store heat, the earth would be a different and colder place. There might even be different life forms. So it is thanks to this greenhouse gas that our planet is so livable. But we also hold him responsible for climate change and its effects. In too large quantities, this (and other greenhouse gases such as methane) binds too much heat. Ultimately, this contributes to our world becoming warmer, with catastrophic consequences.

This climate change caused by greenhouse gases is a complex process to study, but it is clear that carbon dioxide is part of it. There are two sources of it here on Earth: natural and man-made. Natural sources of CO2 provide most of this gas released into the atmosphere. These include oceans, animal and plant respiration, decomposition of organic matter, forest fires and volcanic eruptions. Scientists know of some naturally occurring CO2 deposits in the earth’s crust that could also serve as CO2 sources. There are also “sinks” in which the gas remains trapped for a period of time. The oceans (particularly the Southern Ocean), soil, and forests “suck it up along with other plants.” The same sinks can release their stores of this gas.

Man-made (or “anthropogenic”) sources include power generation, chemical production, agricultural practices, and transportation. Note that most of these involve burning fossil fuels. Fossil fuels are natural gas, coal and oil.

How CO2 circulates over time

The carbon cycle, which helps detect carbon dioxide on Earth. Courtesy NOAA

So we know that carbon dioxide goes through a natural “cycle” in which it is exchanged in the air, on the ground, in the oceans, plants, people and animals. For most of history, this cycle has maintained the seasonal average of atmospheric CO2 at an estimated 280 parts per million (ppm). In modern times, the burning of fossil fuels and other human activities put more CO2 into the cycle and changed its amount in the atmosphere. This pace has accelerated so much that values ​​have risen by 50% in less than 200 years. Today the level of CO2 is about 441 ppm and it keeps rising as we pump more gas into the air. Climatologists assume that with the increase, the global average temperature will continue to rise.

If we look at average global temperatures since historical measurements began (when we pumped less CO2 into the air), the temperature on Earth has risen by about 0.08°C (0.14°F) every decade. Natural variations play some role, but adding more carbon dioxide plays an increasing role. Over time, warming has totaled a 2-degree increase over more than a century. It follows the increasing amounts of this gas in our air. Two degrees is a lot; Even one degree is enough to have a significant impact. To give you an idea, in the distant past, when global averages dropped a degree or two, the Earth experienced what was known as the Little Ice Age.

Warming drives change

A chart showing how global temperatures have changed from 1880 to 2020. Courtesy MET Office Hadley Centre/Climatic Research Unit.

It might not sound like much, but two degrees is enough to drive changes in our weather patterns, water cycles, and other environmental processes. This gradual warming is why experts often refer to it as “global warming.” It’s not like it gets hot everywhere at the same time. This means that the average annual air temperature is increasing. To give you an idea, 2022 was the sixth warmest year since global records began in 1880.

Maps and animations of CO2 sources, sinks and cycles, as obtained from NASA satellite data, show the cycle of this particular gas in great detail. The idea is to help people visually and intellectually understand how our atmosphere is changing over time.

For more informations

Atmospheric carbon dioxide labeled by source
What is climate change?
carbon dioxide 101
Climate Change: Global Temperature

Earth Observatory temperature changes

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