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How Old Is The Universe? – Worldatlas.com

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The universe is both vast and ancient. You may have heard that the universe is about 14 billion years old, yet how exactly is this determined? Knowing the age of the universe may seem like it’s something beyond human capability, yet there are fairly simple ways of determining how old our universe is. However, it is important to note that the age of the universe is still somewhat of a mystery, and future observations will likely reveal more information. There are two primary methods for determining the age of the universe: the oldest stars and the rate of the universe’s expansion

The Oldest Stars

   Illustration of the history of the universe, from the Big Bang till now. 

By knowing the age of the oldest stars, astronomers can estimate how old the universe must be. The oldest known star in the universe is called Methuselah, named after the oldest individual in the bible. Even prior to calculating its age, astronomers knew Methuselah was old based on its composition. Since most elements heavier than hydrogen and helium form within stars, the first stars would have had little to no elements heavier than helium. Methuselah itself is composed almost entirely of hydrogen and helium, with no evidence of many elements heavier than helium. Thus, Methuselah must have formed when the universe contained nothing but hydrogen and helium. This would make Methuselah one of the oldest stars in the universe, yet when astronomers calculated its age, problems arose. Based on observations of other stars and the expansion of space, the best estimates for the age of the universe were around 13.8 billion years old, yet the age of Methuselah was calculated to be 16 billion years old. Obviously a star cannot be older than the universe, so either the age of the universe is wrong or the age of Methuselah is wrong. Future observations have only added to this problem, with most estimates of Methuselah’s age placing it older than the universe or the same age as the universe. Based on observations of the early universe and other stars, it seems like the age of Methusalah is probably wrong, and although the star is among the oldest stars, it likely formed around 13 billion years ago. Observations of other old stars have been consistent with a universe that is between 13 and 14 billion years old. 

Expansion Of Space

CMBR
The Cosmic Microwave Background is the oldest image of the universe. Here, we see the cosmos as it was a mere 380,000 years after the Big Bang, nearly 13.8 billion years ago. 

The expansion of space is perhaps the most reliable method at determining the age of the universe. In fact, the expansion of space was the first hint that the Big Bang actually happened. If the universe is constantly expanding, it means that the universe of the past was smaller than it is today. If you work backwards, you end up at a point where everything in space was condensed into a single point no larger than an electron. By knowing how fast space is expanding, all you need to do is put things in reverse and see how much time has passed since everything was a single point. By using this method, scientists estimate that the universe began in the Big Bang about 13.8 billion years ago. However, as is the case with much of science, future observations and data may reveal more detail about the age of the universe, revealing that the universe could potentially be older or younger than what we currently think. 

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Astronomers identified the most distant globular clusters ever discovered – Tech Explorist

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The Canadian NIRISS Unbiased Cluster Survey (CANUCS) team discovered the most distant globular clusters ever found using the James Webb Space Telescope (JWST). These dense groups of millions of stars may be relics that contain the first and oldest stars in the universe.

This discovery in Webb’s First Deep Field already provides a detailed look at the earliest phase of star formation, confirming the incredible power of JWST.

The nine billion light-year-away “Sparkler galaxy” was the focus of the exquisitely detailed Webb’s First Deep Field image, said the astronomers. The researchers called these compact objects around this galaxy “sparkles,” which appeared as small yellow dots.

According to the research team, these sparkles might either be new clusters of stars actively developing that were formed three billion years after the Big Bang at the height of star formation or old globular clusters. Globular clusters are old collections of stars from the beginning of a galaxy, providing information about the early stages of its development and expansion.

From their initial analysis of 12 of these compact objects, the researchers determined that five of them are not only globular clusters but among the oldest ones known.

Kartheik G. Iyer, Dunlap Fellow at the Dunlap Institute for Astronomy & Astrophysics at the University of Toronto and co-lead author of the study, said, “Looking at the first images from JWST and discovering old globular clusters around distant galaxies was an incredible moment, one that wasn’t possible with previous Hubble Space Telescope imaging.”

“Since we could observe the sparkles across a range of wavelengths, we could model them and better understand their physical properties, like how old they are and how many stars they contain. We hope the knowledge that globular clusters can be observed from such great distances with JWST will spur further science and searches for similar objects.” 

Lamiya Mowla, Dunlap Fellow at the Dunlap Institute for Astronomy & Astrophysics at the University of Toronto and co-lead author of the study, said, “These newly identified clusters were formed close to the first time it was even possible to create stars. Because the Sparkler galaxy is much farther away than our own Milky Way, it is easier to determine the ages of its globular clusters.

“We are observing the Sparkler as it was nine billion years ago, when the universe was only four-and-a-half billion years old, looking at something that happened a long time ago. Think of it as guessing a person’s age based on their appearance—it’s easy to tell the difference between a 5- and 10-year-old, but hard to tell the difference between a 50- and 55-year-old.”

The Sparkler galaxy is special because it is magnified by a factor of 100 due to an effect called gravitational lensing—where the SMACS 0723 galaxy cluster in the foreground distorts what is behind it like a giant magnifying glass. Moreover, gravitational lensing produces three separate images of the Sparkler, allowing astronomers to study the galaxy in greater detail.

CANUCS team lead Chris Willott from the National Research Council’s Herzberg Astronomy, and Astrophysics Research Centre said, “Our study of the Sparkler highlights the tremendous power in combining the unique capabilities of JWST with the natural magnification afforded by gravitational lensing. The team is excited about more discoveries when JWST turns its eye on the CANUCS galaxy clusters next month.” 

The researchers combined new data from JWST’s Near-Infrared Camera (NIRCam) with HST archival data. NIRCam detects faint objects using longer and redder wavelengths to observe past what is visible to the human eye and even HST. Both magnifications due to the lensing by the galaxy cluster and the high resolution of JWST made observing compact objects possible.

The Canadian-made Near-Infrared Imager and Slitless Spectrograph (NIRISS) instrument on the JWST confirmed that the objects are old globular clusters because the researchers did not observe oxygen emission lines—emissions with measurable spectra given off by young clusters that are actively forming stars. NIRISS also helped unravel the geometry of the triply lensed images of the Sparkler.

Marcin Sawicki, Canada Research Chair in Astronomy, professor at Saint Mary’s University, and study co-author, said, “JWST’s made-in-Canada NIRISS instrument was vital in helping us understand how the three images of the Sparkler and its globular clusters are connected. Seeing several of the Sparkler’s globular clusters imaged three times made it clear that they are orbiting around the Sparkler galaxy rather than being simply in front of it by chance.” 

Journal Reference:

  1. The Sparkler: Evolved high-redshift globular cluster candidates captured by JWST. The Astrophysical Journal Letters (2022). DOI: 10.3847/2041-8213/ac90ca

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NASA Releases Most Detailed Photos Of Jupiter Moon Europa In Decades – Fatherly

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NASA keeps dropping more photos of incredible, jaw-dropping outer space in views we’ve never seen before. The newest images don’t come from the James Webb Space Telescope, though, which has been giving us wow-worthy images lately. These new photos come from NASA’s Juno probe — and they show the first photos of Jupiter’s Europa in decades.

The Juno probe is part of NASA’s New Frontiers Program and was launched into space in 2011 to get close to Jupiter and learn more about the distant planet. According to NASA, the probe reached its destination in 2016, and the new photos were taken when the probe made its closest pass in 22 years to the icy moon known as Europa.

“Rugged terrain features are easily seen, including tall shadow-casting blocks, while bright and dark ridges and troughs curve across the surface. The oblong pit near the terminator might be a degraded impact crater,” JPL officials wrote of Juno’s flyby imagery on September 29.

The moon near Jupiter is similar in size to Earth’s moon. However, it has a much different history and formation, per NASA. Europa has a cold crust overtop an ocean that researchers have long thought may be capable of supporting life similar to what we have here on our planet.

In the latest flyby, the Juno probe returned some of the “highest-ever resolutions pictures,” according to Space.com. And scientists were able to get a good look at the atmosphere and environment of the icy moon.

NASA/SWRI/MSSS

“The science team will be comparing the full set of images obtained by Juno with images from previous missions, looking to see if Europa’s surface features have changed over the past two decades,” said Candy Hansen, a Juno co-investigator who leads planning for the camera at the Planetary Science Institute in Tucson, Arizona. “The JunoCam images will fill in the current geologic map, replacing existing low-resolution coverage of the area.”

During the flyby, the trajectory of the Juno probe was modified a bit to help reduce the time it takes for it to orbit Jupiter. Instead of taking 43 Earth days to orbit, it will only take 38 days, hopefully allowing researchers to continue to get more data on the sixth largest Moon in our solar system.

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'Shiny, sparkly object' in James Webb space image – BBC

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NASA

Astronomers have made a sparkling discovery in what was the very first full-colour image released from the new super space telescope James Webb.

The picture, presented to the world in July by US President Joe Biden, shows a fantastically deep view of the cosmos, billions of years into the past.

And it’s in that remarkable vista that researchers have now picked out what they believe to be the most distant globular clusters ever identified.

Globulars are dense star collections.

What’s more, these stars are generally really quite old and relatively pristine: they have fewer of the heavier chemical elements that taint more modern stars such as our Sun.

Our Milky Way Galaxy, in which our Sun lives, has more than 100 of these compact groupings littered around itself, but when and how they formed is still something of a puzzle.

The Biden Webb image should improve our understanding.

The Sparkler graphic

The picture, called SMACS 0723, is an example of what’s referred to as a gravitational lens. It shows a set of massive foreground galaxies that have magnified and bent the light coming from galaxies in the background.

And it’s one particularly pretty galaxy in the far distance that’s caught the eye of astronomers at the University of Toronto.

They’ve dubbed it “the Sparkler Galaxy” because it’s surrounded by small yellow-red dots – by “sparkles”.

Only with James Webb’s extraordinary power are these dots resolvable. You couldn’t see them with that other great observatory, Hubble, for instance.

The Toronto team wondered at first whether the sparkles were even associated with the Sparkler Galaxy. Was it possible they were just sitting out there on their own instead, a long way in front or behind the Sparkler? But it soon became obvious that they were associated because the Sparkler Galaxy itself is projected three times in the SMACS 0723 image.

That’s just how gravitational lenses work sometimes: they can not only magnify background objects but also distort them and multiply their appearance.

And in each of the three versions of the Sparkler Galaxy, the same dots are present.

Sparkler graphic

The team’s contention is that the sparkles are globular clusters just like the globulars seen around our Milky Way today, except we’re seeing these dots much, much earlier in the history of the Universe.

We see the Sparkler as it was nine billion years in the past, or about 4.5 billion years after the Big Bang.

“We are finding these globular clusters to be very massive,” explained Dr Lamiya Mowla from Toronto’s Dunlap Institute for Astronomy & Astrophysics. “We also find them to be very old.

“They could have formed in a burst at what we call ‘cosmic noon’, at the peak of star formation at about 10 billion years ago. But their colour isn’t right. For something to be relatively young, it has to be bluer, and what we’re finding is that they’re much redder than we expected them to be, which means they must be older, even at that very early time,” she told BBC News.

The team contends the stars in these globular sparkles probably formed just a few hundred million years after the Big Bang. It’s even possible, the astronomers say, that the sparkles contain some of the very first stars ever to form in the Universe.

“They’re the Holy Grail, right?” said Dr Mowla.

“Everyone is looking for those stars and when we first opened the SMACS image, we too were searching for the furthest stuff, the farthest things. And then we literally got sidetracked by the most shiny, sparkly object.”

The Toronto research programme, called the CAnadian NIRISS Unbiased Cluster Survey (CANUCS), will now examine five more gravitationally lensed views from James Webb similar to its SMACS image.

“That’s really going to push up the number of galaxies that we find with sparkles around them,” said Dunlap Institute postdoctoral fellow Dr Kartheik Iyer.

“We want to know how ubiquitous these sparkles are. Did we just find a special galaxy or is this something we can expect to see more of when we have a representative sample from Webb,” he told BBC News.

The Toronto Sparkler research is published in The Astrophysical Journal Letters.

JWST history

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