Occasionally I see references in Astronomy to the speed of something as “supersonic.” I’m having trouble reconciling this term with velocities typically found among astronomical objects. Wouldn’t “relativistic” be closer to the truth? Anything close to sonic speeds in Earth’s atmosphere wouldn’t cover much distance in outer space. Peter IanchiouTucson, Arizona One would certainly thinkContinue reading "What does the term ‘supersonic’ mean in astronomy?"

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Researchers say the isolated white dwarfs Gandalf and Moon-Sized define a new class of stellar remnant because they share five traits, including X-ray emission. Across the immense scale of the Universe, a single unusual object can prompt astronomers to look for others like it, sometimes leading to the recognition of an entirely new class of [...]

A new method could improve cosmology research by analyzing supernovae together with the galaxies that host them. An international collaboration led by scientists at the Institute of Cosmos Sciences of the University of Barcelona (ICCUB) has created a new approach that may sharpen what researchers can learn about how the Universe expands and what dark [...]

Astronomers have spotted a “planet factory” in space that could explain the origins of bizarre meteorites scattered across the Earth.

Lurking beyond Jupiter’s orbit, the ring-shaped region is packed with gas and dust that may have allowed it to serve as a breeding ground for so-called planetesimals, mile-length solid masses that can become the building blocks planets, when the solar system was in its infancy.

But that’s not all. In computer simulations described in a new study published in The Astrophysical Journals, the team found that the region also produced planetesimals of different compositions, perhaps making it one of the most influential planet-forming regions in our star’s domain.

“Different types of planetesimals apparently formed in the same region of the early dust and gas disk, only at different times. The region just outside Jupiter’s orbit offered excellent conditions for this,” study coauthor Joanna Drążkowska, an astrophysicist at the Max Planck Institute for Solar System Research, said in a statement about the work.

The mystery stems from a class of planetesimals called carbonaceous chondrites that formed around two to four million years after the solar system first came together. Though most planetesimals are thought to have been ejected as the solar system matured, traces of these survive as meteorite fragments that frequently bombard our planet, and it’s the rarer and unusually carbon heavy ones — our aforementioned chondrites — that prove most intriguing. They’re composed of distinct dust grains, but the proportion of these grains varies dramatically over time, with one generation made of notably crumbly grains, and others sturdier grains. What region could’ve formed such a medley of planetesimals in a short window was unknown.

A so-called “dust trap” just beyond Jupiter provides a tidy explanation, the researchers found. When the Sun was young, it was encircled by a huge disk of material in which the planets eventually formed. When Jupiter came along with its incredible mass, it sucked up most of the planet-forming material around its orbit, creating a gap in the so-called protoplanetary disk. A knock-on effect of this was that it also created a ring of higher pressure gas outside the neighborhood it cleared, trapping dust grains that clumped together into pebbles, which could eventually birth planetesimals.

In simulations modeling both microscopic particle collisions and large-scale movements in the protoplanetary disk, the researchers demonstrated that some particles could become trapped in certain regions, like the one near Jupiter. Further underscoring the planet’s role, they also found that it acted as a barrier for larger, more sturdy particles than smaller ones. This was all occurring as already-forming planetesimals sucked up some of the free-floating material. Over time, these dueling processes helped create planetesimals of two distinct generations. In the first 500,000 years, the abundance of crumbly grains dropped before rising over the next million years.

These findings, if borne out, could have broader implications for our understanding of the solar system’s evolution.

“There is strong evidence that dust traps were the preferred birthplace of planetesimals in our solar system,” Drążkowska said.

“For the first time, we have succeeded in accurately reproducing the results of laboratory studies of meteorites using computer simulations of the early solar system,” added coauthor Thorsten Kleine, Max Planck cosmochemist. “The meteorites serve, so to speak, as a touchstone for theories of planetary formation.”

More on space: Scientist Suggests That 3I/ATLAS May Have Seeded Life as It Careened Through Our Solar System

The post Scientists Spot What Appears to Be a Ring-Shaped “Planet Factory” Deep Out in Space appeared first on Futurism.

The James Webb Space Telescope (JWST) was designed to give us the ability to look at one of the earliest periods in the evolution of the Universe, a time when some of the earliest stars were putting out enough light to ionize the hydrogen that accounted for almost all of the normal matter present at the time. There were lots of ideas about what we might see, but the Universe is full of surprises.

One of the first surprises was the existence of what picked up the moniker "little red dots," which are exactly what their name suggests. After some initial arguments, it became clear that these were early versions of the supermassive black holes that presently sit at the center of almost every galaxy. Now, gravitational lensing has allowed astronomers to confirm that a little red dot is little more than a supermassive black hole without much in the way of a galaxy around it.

Making a little red dot bigger

The little red dot in question is called Abell 2744−QSO1, and gravitational lensing has both magnified it and caused it to appear three times in the vicinity of the galaxy cluster that did the lensing. Based on details in its spectrum, we're looking at the object as it appeared just 700 million years after the Big Bang.

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© NASA, ESA, CSA, Lukas Furtak, Alyssa Pagan

There are more opportunities to access space than ever, thanks to a bevy of commercial rockets, some with reusable boosters, led by SpaceX's workhorse Falcon 9. So why is NASA launching fewer telescopes and planetary science missions than it did a quarter-century ago?

The answer is complex. It is not necessarily the money. The space agency's science budget this year is $7.25 billion, roughly the same as it was in 2000, adjusted for inflation. This is despite attempts by the Trump administration to drastically reduce NASA science funding.

In the early months of his tenure, NASA Administrator Jared Isaacman's focus has been on human spaceflight and the Moon. This isn't terribly surprising given NASA's wildly successful Artemis II mission carrying four astronauts around the Moon last month. Since taking office in December, Isaacman has announced an overhaul of the Artemis program, canceling a space station to be built in orbit around the Moon in favor of construction of a base on the lunar surface.

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© NASA/JPL-Caltech/Space Science Institute

The James Webb Space Telescope (JWST) was designed to give us the ability to look at one of the earliest periods in the evolution of the Universe, a time when some of the earliest stars were putting out enough light to ionize the hydrogen that accounted for almost all of the normal matter present at the time. There were lots of ideas about what we might see, but the Universe is full of surprises.

One of the first surprises was the existence of what picked up the moniker "little red dots," which are exactly what their name suggests. After some initial arguments, it became clear that these were early versions of the supermassive black holes that presently sit at the center of almost every galaxy. Now, gravitational lensing has allowed astronomers to confirm that a little red dot is little more than a supermassive black hole without much in the way of a galaxy around it.

Making a little red dot bigger

The little red dot in question is called Abell 2744−QSO1, and gravitational lensing has both magnified it and caused it to appear three times in the vicinity of the galaxy cluster that did the lensing. Based on details in its spectrum, we're looking at the object as it appeared just 700 million years after the Big Bang.

Read full article

Comments

© NASA, ESA, CSA, Lukas Furtak, Alyssa Pagan

There are more opportunities to access space than ever, thanks to a bevy of commercial rockets, some with reusable boosters, led by SpaceX's workhorse Falcon 9. So why is NASA launching fewer telescopes and planetary science missions than it did a quarter-century ago?

The answer is complex. It is not necessarily the money. The space agency's science budget this year is $7.25 billion, roughly the same as it was in 2000, adjusted for inflation. This is despite attempts by the Trump administration to drastically reduce NASA science funding.

In the early months of his tenure, NASA Administrator Jared Isaacman's focus has been on human spaceflight and the Moon. This isn't terribly surprising given NASA's wildly successful Artemis II mission carrying four astronauts around the Moon last month. Since taking office in December, Isaacman has announced an overhaul of the Artemis program, canceling a space station to be built in orbit around the Moon in favor of construction of a base on the lunar surface.

Read full article

Comments

© NASA/JPL-Caltech/Space Science Institute

The universe is around 14 billion years old, but scientists theorize that no stars formed for the first several hundred million years, during an era known as the cosmic dark ages. They refer to the first billion years or so after this, when stars formed, as the cosmic dawn. At that time, the very oldest galaxies first assembled from collections of gas and plasma. 

As these galaxies assembled and more material became available, the number of stars formed each year increased. Around 2 to 3 billion years after the Big Bang, galaxies grew faster than they ever would, producing stars at the highest rate in the universe’s history. This era is called cosmic noon.

Researchers from the Netherlands recently investigated 3 distant galaxies whose light began its journey to Earth during cosmic noon. They selected targets from a set of ancient star-forming galaxies identified in the ALMA – Archival Large Program to Advance Kinematic Analysis or ALMA-ALPAKA project. Of these, they chose to study 3 galaxies labeled ID1, ID3, and ID13.

They combined 2 different types of data to produce a detailed description of these galaxies. First, they collected data from an enormous telescope comprising 66 antennas in Chile, known as the Atacama Large Millimeter/submillimeter Array or ALMA. They used ALMA to detect radio-wave emissions from carbon monoxide and elemental carbon in these galaxies. The researchers stated that studying these chemicals in distant galaxies could reveal how their free-floating gas clouds move. They also used publicly available data from JWST’s Near Infrared Camera, or NIRCam, to determine how much light the galaxies’ stars emitted. By analyzing cosmic noon galaxies in multiple different ways, the team aimed to measure their masses and the relative contributions of regular matter and dark matter.

They used a computer program developed by other astronomers to interpret the JWST data as a series of maps showing the distribution of stars across each galaxy. They used this light-emission data to estimate the total mass of all the stars in these galaxies. Then they developed an original computer program to map the distribution of gas through each galaxy using the ALMA data. The team used these maps to create plots, known as rotation curves, which show how fast particles orbit each galaxy’s center as a function of their distance from it. 

The astronomers used these rotation curves to estimate the amount of dark matter in each galaxy. They explained that this method works because dark matter is totally invisible, but it still exerts a gravitational pull. Its gravitational pull causes visible material like stars and gas closer to the edges of these galaxies to move faster than they would in galaxies without dark matter. 

The team found that these galaxies had between 39 and 80 billion times the mass of our sun, or solar masses, in stars. They had between 4 billion and nearly 16 billion solar masses worth of free-floating gas. And they had from 1 trillion to 31 trillion solar masses of dark matter.

However, when the team compared the light-emission data with the rotation curves, they found a discrepancy. Typically, dark matter resides in a shell or halo surrounding a galaxy, meaning it should mostly affect material near the galaxy’s outer edge. Since astronomers don’t usually have to account for dark matter near a galaxy’s center, they can calculate the total mass of center material based on the amount of gas and stars they see there. But near the centers of these galaxies, the team found that the masses they derived from the light emissions were less than what they calculated from the rotation curves. 

They proposed multiple potential explanations for this discrepancy. First, they suggested that the halo shape might not be a good model for the dark matter distribution in all galaxies, meaning that cosmic noon galaxies could contain dark matter near their centers. Second, they suggested that stars could be packed tightly in the center of these galaxies, blocking each other’s light emissions. Third, they suggested that galaxy ID1 could have a supermassive black hole as big as 1.5% its total stellar mass at its center.

The team concluded that they now have a detailed picture of the mass distribution in these cosmic noon galaxies, but the reason for their center mass discrepancies remains elusive. They suggested that a complex relationship exists between the dark matter halos and the rest of the material within these galaxies. They indicated that future astronomers could adapt their methods to study the distribution of material in other distant galaxies studied by ALMA-ALPAKA and forthcoming galactic surveys.

The post Characterizing galaxies at “cosmic noon” appeared first on Sciworthy.

The biggest open problem in the foundations of physics is that Einstein’s theory of gravity, General Relativity, does not cooperate with quantum mechanics. Physicists have tried to solve this issue by coming up with a theory of quantum gravity, but those theories fall apart when you need them most – inside of black holes and at the Big Bang. Recently, though, physicists published a new

The Star Wars series depicted alien heroes fighting against evildoers and their planet-destroying superweapons “a long time ago in a galaxy far, far away.” But what do scientists really know about alien planets in distant galaxies beyond our own? These worlds, known as extragalactic exoplanets, are expected to exist, assuming the Milky Way is no different from other galaxies. However, we have yet to find them since other galaxies are still too far, far away for modern exoplanet-observing techniques.

Recently, a team of astronomers analyzed a stream of over 700,000 stars that the Milky Way likely absorbed from the dissolving Sagittarius dwarf galaxy. These stars are very distant, so the team investigated whether any of them host large, close-orbiting exoplanets called hot Jupiters, which are relatively easy to find.  

They established a set of 3 criteria to narrow down their list of stars. First, each star should appear bright enough when observed by the Transiting Exoplanet Survey Satellite, or TESS, to ensure high-precision results from the team’s data processing software. Second, each star must have more than a 50% likelihood that it originated from the Sagittarius dwarf galaxy, based on motion and position measurements from the Gaia mission. Finally, each star should have a radius of less than twice the Sun’s, as it’s easier to find planets around smaller stars. They used these criteria to limit their candidate list to around 20,000 stars.

After selecting their candidate stars, the team analyzed publicly available TESS catalog data using the software packages eleanor and TESS-Gaia Light Curve, or TGLC. These tools allowed them to plot each star’s brightness over time, in graphs called light curves. Then, the astronomers looked for periodic brightness dips in these light curves as evidence that an exoplanet passed in front of the star. From this, they excluded several thousand additional stars with too much light interference from their surroundings, reducing their final sample size to just over 15,000 stars.

To find hot Jupiters, the team looked for brightness dips at intervals of 14 hours to 10 days, which is the typical orbital period range for hot Jupiters. Then, they used geometry to derive each exoplanet’s radius from the fraction of the starlight it blocked. They excluded candidates with dips corresponding to objects with radii at least twice that of Jupiter’s, as these are likely caused by orbiting companion stars rather than exoplanets.

Among all the stars they surveyed, the team’s strongest candidate to host a hot Jupiter was a star labeled TIC 92223525. They calculated that this star could host an exoplanet with a radius 1.76 times the size of Jupiter’s and an orbital period of 7.2 days. However, when they reviewed this star’s light curve, they found that it was likely contaminated by its neighbor, TIC 92223526. The regular brightness dips from this system of orbiting stars mimicked that of an exoplanet, creating a false positive for TIC 92223525 that was difficult to detect during initial screening. As a result, the team ultimately excluded this candidate, leaving them with no confirmed exoplanets.

The researchers drew several conclusions from their inability to find hot Jupiters in their sample of stars from the Sagittarius dwarf stream. They estimated that if more than 1% of these stars hosted hot Jupiters, it would have been highly unlikely not to detect one in a sample of over 15,000 stars. This places an upper limit of about 1% on the occurrence rate of hot Jupiters. If this estimate is accurate, then even an ideal exoplanet search team would need to examine over 11,000 stars to find an extragalactic hot Jupiter. Accounting for more realistic levels of scientific uncertainty, a future team would likely need to study at least 80,000 stars to find one. 

Although this survey of the Sagittarius dwarf stream yielded null results, the team suggested that future researchers continue searching it and other star streams from different galaxies. Scientists have identified over 20 such streams in the Milky Way. Researchers studying these streams could find the first extragalactic exoplanet or provide evidence that other galaxies produce fewer hot Jupiters than our own. But let’s hope none of them find the first extragalactic Death Star!

The post Searching for planets in a galaxy far away appeared first on Sciworthy.

That life might have come to earth traveling through outer space used to be a fringe theory called ‘panspermia’. But in the past decade or so, we have seen an interesting shift in how scientists regard the idea. Let’s take at one new study that might support ‘panspermia,’ as well as other facts that support the theory.

The Fermi Paradox is the question of why we haven’t been contacted by any extraterrestrial species. In a recent paper, astrophysicists analyzed the paradox by instead examining how civilizations with the ability to send signals through space might develop. Unfortunately for us, their findings are quite bleak – but let’s take a look anyway.

Stars are mostly made of 2 elements: hydrogen and helium. While this has always been the case, those 2 elements and lithium were the only elements in existence when the Big Bang occurred around 14 billion years ago. When the first stars exploded, they released those primordial elements, as well as heavier elements produced by nuclear fusion inside them. 

Astronomers call all elements heavier than hydrogen and helium metals, a term chemists use quite differently. Subsequent generations of stars, including the Sun, formed in clouds of gas and dust enriched with these metals, such as carbon, oxygen, magnesium, and silicon. Scientists estimate that modern stars are 1% to 5% metal by mass.

Astronomers claim there is no solid evidence that stars contain exceptionally high amounts of metals, but some, called chemically peculiar stars, appear to. Astronomers study stars by looking at the patterns of light they emit, called spectra. Each element produces a unique light pattern, so astronomers can compare the light patterns in a star’s spectra to determine how much of each element is present, especially in the outer layers of the star. Researchers theorize that chemically peculiar stars don’t actually have more metals than average stars. Instead, they think that metals from their interiors diffuse to their outer layers more than in most stars.

A team of researchers from the American Association of Variable Star Observers and Masaryk University in Czechia recently observed 85 chemically peculiar stars to understand their behavior and better classify them. For their study, they first used the General Catalog of CP Stars, published in 2009 in Astronomy & Astrophysics, to identify targets across the 4 classes of these stars, labeled CP1 through CP4. CP1 stars have strong spectral patterns for iron and other heavy elements, CP2 stars have strong patterns for silicon, chromium, strontium, and europium, CP3 stars have strong patterns for mercury and manganese, and CP4 stars have either unusually weak or usually strong helium patterns. 

The team compiled a list of 85 stars to observe, then used the BRIght Target Explorer (BRITE) Constellation to monitor changes in their brightness. The BRITE Constellation is a set of 5 satellites equipped with telescopes and cameras for either red or blue light. Using the BRITE Constellation, the team monitored each star for several days. 

They found that 74 of these 85 chemically peculiar stars varied in brightness during their survey. They attributed this to the varied abundance of metals on their surfaces, which would form dark patches that go in and out of view from Earth’s perspective as the stars rotate. The team observed that 6 of these 74 stars appeared to change in brightness over multiple periods. They were surprised by this result because a star’s brightness wouldn’t vary over multiple periods if the changes were due to rotation. They compared their findings to data other scientists had collected from these stars with the Transiting Exoplanet Survey Satellite, or TESS, and found that all 6 stars had been misclassified as chemically peculiar stars.

The other 11 chemically peculiar stars appeared to show no periodic changes in their brightness, suggesting that they’re stationary. The team claimed that some CP1 and CP3 stars don’t rotate, but they identified cases in which CP2 and CP4 stars that ought to rotate appeared to be stationary. They suggested 2 potential reasons for this. One is that these CP2 and CP4 stars are misclassified, requiring more thorough analysis of their spectra to confirm their classifications. The other is that the stars rotate slowly, with rotational periods of 50 days or longer, which would be difficult to distinguish from those of totally stationary stars.

The team concluded that more astronomers should revisit the historical classifications of stars, especially as technology advances and more space-based telescopes become available. This strategy would allow future researchers to draw better data from research archives and catalogs. Additionally, they claimed that their method of pairing long-term monitoring via small satellites with TESS data is well-suited for refining classifications, identifying misclassified objects, and further exploring the structure and mechanics of chemically peculiar stars.

The post What makes ‘chemically peculiar stars’ peculiar? appeared first on Sciworthy.

MOND (Modified Newtonian Dynamics) is a theory of gravity that explains the physical phenomena we observe in galaxies with surprising accuracy, but it falls apart when it’s applied to galaxy clusters. The widely accepted dark matter theory, meanwhile, can apply to both. But according to new research by astrophysicists, observational data shows that our universe is full of more dead stars than we