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What are the limits of our universe? – EL PAÍS USA

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During the 1920s, a debate about the size of the universe and the nature of the nebulae – diffuse objects of which several thousand were catalogued – raged among astronomers. Some scientists argued that they were gaseous objects located within our galaxy and that this made up the entire universe, while others asserted that they were actually star systems, similar to the Milky Way, “island universes” that looked diffuse in the distance. The argument was settled by Edwin Hubble, who, using the relation obtained by Henrietta Swan Leavitt, was able to measure the distance to the Andromeda nebula, the only one that is visible to the naked eye from the northern hemisphere of the Earth. The value obtained by Hubble was much larger than the size of the Milky Way, which proved the existence of other galaxies and dramatically increased the size of the universe.

Astronomical distances are usually determined in light years. A light year is the distance that light travels in one year; approximately nine trillion kilometers. The diameter of the Milky Way is 900 quadrillion kilometers, and the distance to Andromeda is 22.5 quintillion kilometers. These are huge distances, even if Andromeda is still part of the group of galaxies we refer to as the Local Group – that is, our neighborhood. The fact is that the universe is so vast that we cannot see it in its entirety, because after 13.8 billion years of life, there are some regions whose light has not reached us yet.

The universe that we can see – the known universe – is a sphere whose radius marks the distance between the regions that emitted the radiation that we observe today as cosmic microwave background radiation and our planet. If the universe were static, this boundary, what we call the particle horizon, would be 13.8 billion light years away. However, the distance it much longer: 46 billion light years.

The reason is that the universe is expanding, which Hubble also explained in the article A relation between distance and radial velocity among extra-galactic nebulae, published in 1929. Hubble carefully measured the speeds and distances of a sample of galaxies, showing that they are moving away from us in all directions, gaining speed as they get farther away. Although Hubble was very cautious in his conclusions, the implications were clear. Only five years before, the scientist’s work had dramatically expanded the size of the universe; now, it expanded the universe itself.

A raisin cake is often used as a way to illustrate the expanding universe. When we put the cake in the oven and it starts to grow, every raisin sees the rest move away. When it doubles in size, two raisins that initially were a centimeter apart will be two centimeters apart, while those that were three apart will be six apart. This means that during the same time, the distance between the farthest raisins will have increased three times more than the distance between the closest ones, that is, they will have moved away three times faster.

The background radiation was emitted in the early stages of the universe, but its light had to travel through an expanding universe for 13,800 years before finally reaching us. However, all

this time those regions have continued to move away, and the spots we see in the background radiation have evolved into galaxies and galaxy groups similar to those around us. If we could stop the expansion of the universe right now, the light from those galaxies would take another 46 billion years to reach us. But we cannot stop the expansion of the universe, and we will never be able to see the galaxies that these specks have become, no matter how long we wait. That is because those regions move away from us at speeds greater than the speed of light, so the light, no matter how hard it tries, will never be able to cover the distance that separates it from us. In this sense, the particle horizon, the known universe, marks the visible limit of the universe’s past, but not the universe with which we can interact.

Recently we were able to see, in images obtained with the James Webb Space Telescope, galaxies whose light could have been emitted 13.5 billion years ago. Newly formed galaxies inhabiting a baby universe, barely 300,000 years old. They are, in a way, pictures of ghost galaxies in a region of the universe with which we will never be able to interact. Can we say, then, that they are still part of our universe?

Let us then define the limit of the universe with which we can interact. Within this limit – and as long as we have enough time – we can still receive the light that the galaxies emit now. This is the region of the universe whose expansion rate is below the speed of light, and its boundary is 16 billion light years away. That is called the event horizon and it marks the limit of the universe with which we can exchange information.

The sad news is that if the most accepted models of the universe are correct, the number of galaxies that we will be able to see in the future will diminish until everything disappears from our sight. Well, maybe not everything, because not all regions of the universe are expanding. Like the raisins in our cake, galaxies don’t expand; neither does the Earth, the trees, or we. The local Group we are in is not expanding and, in fact, because of gravity, the Andromeda galaxy is moving closer to us. However, this gravity will cause all the galaxies that do not move away to get closer and closer until they merge into a single one, which will be the only one that the astronomers that inhabit it then will be able to observe. They will not be able to measure the speeds or distances of other galaxies to know that the universe is expanding, and they will probably end up thinking, like the astronomers of the 19th century, that the universe consists of a single galaxy: their own.

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Red Deer-area boy discovers ancient shark's tooth in his yard – Red Deer Advocate

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A dinosaur-loving Red Deer-area boy found a 60 million-year-old fossilized shark tooth — right in his own front yard.

Max Maurizio, 7, was exploring gravel near his house on an acreage southeast of Red Deer on Monday, when he spotted something that didn’t look like other rocks. It was sharp at one end and about an inch and a half long.

“He came running into the house saying, ‘I found a tooth! I found a tooth!” recalled his mom, Carly Maurizio.

At first, Max’s parents assumed it came from one of their cats. But Carly carefully examined it and decided, “‘it looks pretty old…”

Intrigued by Max’s discovery, his dad, Claudio Maurizio, emailed a photo of the tooth to the world-renowned Royal Tyrrell Museum of Palaeontology in Drumheller.

On Tuesday, an emailed response arrived from the museum. The photo had been passed on to Dr. Don Brinkman, an expert on fossil fish and turtles.

Brinkman believes the fossilized tooth very likely belonged to the genus Scapanorhynchus — a type of extinct ancient shark with an elongated snout, whose closest living relative is the goblin shark.

“That is an interesting find,” stated Brinkman in the email.

Scapanorhynchus reached a length of about three metres and was a fully marine animal, “so it is a little unusual getting it in the Red Deer area. However, I have seen a tooth of this genus from exposures of the Horseshoe Canyon Formation in the Tolman Bridge area,” east of Trochu, wrote Brinkman.

He noted rocks around Red Deer are from the Paskapoo Formation and are about 60 million years old.

From 100 million to 66 million years ago, the Prairies were covered by a warm inland sea. Scientists believe this Western Interior Seaway extended 3,000 km, from the Arctic Ocean to the Gulf of Mexico, was 1,000 km wide and 700 metres deep.

The ancient water body contained a wide array of life, including sharks, bony fish, marine reptiles, birds, snails, ammonites and other mollusks.

The Maurizio family appreciates the information the museum provided on the tooth.

Max is particularly thrilled by his find and wants to become a paleontologist someday, said Carly.

Claudio noted his son is always noticing things that other people don’t. Once, before heading on a nature walk with his grandfather in Ontario, Max predicted he would find a bone — and sure enough, he did discover a small piece of wild animal bone, recalled his father.

Since Max has always been fascinated by dinosaurs, the whole family, including younger brother Meyer, regularly camp at Drumheller and visit the museum at least once a year, said Carly.

“Even when we go on little hikes or regular walks, Max is always looking down at the ground, looking for fossils… It’s quite remarkable that they can be found literally anywhere, even in your own yard,” she added.



lmichelin@reddeeradvocate.com

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Here’s a close up of the ancient shark’s tooth Max Maurizio, age seven, found in his Red Deer County yard. (Contributed photo).

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This solar storm strike on Earth triggered a Mysterious phenomenon called ‘STEVE’ – HT Tech

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On August 7 and 8, an unexpected solar storm event on Earth displayed a mysterious and rare sky phenomenon called STEVE or Strong Thermal Emission Velocity Enhancement. What is it and how can it affect us? Find out.

We have always associated solar storms with aurora displays, damage to man-made satellites, radio blackouts and GPS disruptions, but it turns out that solar storms can trigger more mysterious phenomenons than that. The August 7 and 8 solar storm, which came as a surprise, caused a strange space phenomenon that left even the scientists puzzled. Many reported seeing a bright stream of light across the sky which was not like any aurora even seen. The question that arises now is what was that stunning light and can it affect us somehow?

The event was first reported by SpaceWeather.com which noted on its website, “During yesterday’s surprise geomagnetic storm, hot ribbons of plasma flowed through Earth’s magnetosphere. The name of this phenomenon is ‘STEVE’ — short for Strong Thermal Emission Velocity Enhancement. It was also sighted in Montana and Pennsylvania”.

The mysterious phenomenon to be born out of a solar storm is called STEVE

STEVE was seen in many locations in the higher latitudes of the northern hemisphere and reportedly lasted about 40 minutes to an hour. While not much is known about these purple streams of light, we do know some facts about it.

STEVE is a very recent discovery. It was first observed in 2017 by citizen scientists and aurora hunters in northern Canada, according to Live Science. The purple glow is formed due to excessively hot (more than 3000 degrees Celsius) gas ribbons that move through the magnetosphere of the Earth. These gas ribbons typically move much faster than the air surrounding it and when it comes in contact with the radiation of solar storms, it gives out a band of glowing color. These are different from auroras because they are not caused by solar radiations colliding with atoms of oxygen and nitrogen through a process called refraction.

While this is still a superficial understanding of the chemical and physical activities that are taking place to cause this strange phenomenon, it does make for a stunning view across the sky. As for whether it can affect us, so far no evidence shows that these light displays are in any way harmful for us or the planet.

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Meteor Showers Taking Place Thursday and Friday Night – NorfolkToday.ca

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A meteor shower you won’t want to miss.

Gary Boyle, The Backyard Astronomer, tells us we are currently passing through the dusty debris of Comet 109P/Swift-Tuttle.


It last appeared in 1992, and will return again in 2125.

He said the shower is lasting all night long, but 2 a.m. would be the time to see the most meteor.

The Backyard Astronomer suggested keeping an eye out for other things in the sky, as well.

Boyle added the next large shower will be in mid-December, but this one might be a little warmer to sit outside and watch.

Written by Ashley Taylor

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