Space Exploration
The spin of a supermassive black hole has been measured for the first time using a destroyed star
There are bright bursts of energy called tidal disruption events (TDEs) that happen when a supermassive black hole eats something. Most of the time, it’s a star that was ripped apart because it was so close. Some of the snack is thrown away, but the stellar plasma that is left over forms a hot disk around the black hole. Since this disk shakes, astronomers have now figured out how to use that shaking to figure out how fast black holes spin.
This TDE is known as AT2020ocn. Scientists found that the star’s X-ray emissions seemed to reach their brightest point every 15 days and that this happened more than once. It is thought that this is because the disk’s rotation affects the black hole’s rotation. A supermassive black hole’s gravity is so strong that it bends space-time around it wildly, and when it spins, it pulls space-time with it.
The lens-thirring precession is the name of this effect, but most people can’t see it. Since black holes don’t give off light, the precession can’t be seen. That is, unless all of a sudden you have something that shines, like the remains of a star that just died. They used that theory and guesses to find out that the black hole’s spin is less than a quarter of the speed of light.
Over the 200 days that the object was seen, the X-ray flashes were seen 130 of those days. Once that was over, the disk stopped spinning. The NICER telescope was used to make the observations. It is an X-ray telescope that is attached to the International Space Station. NICE stands for Neutron star Interior Composition ExploreR.
“It was important to catch this early because this precession, or wobble, should only be there early on,” “Any later, and the disk would no longer wobble,” said Dheeraj “DJ” Pasham, the lead author from the Massachusetts Institute of Technology.
Figuring out the spin of supermassive black holes is important because it will help us understand how these objects grow. If supermassive black holes mostly grow by accretion, the small amount of mass falling on them will make them spin faster. Collisions between black holes, on the other hand, would make the spin smaller because the spins of two different black holes would not be aligned.
This first measurement showed that a TDE can be used to figure out the spin of a black hole and that current and future telescopes can gather a group of objects. From these observations in the future, we might be able to get a general idea of how supermassive black holes have changed over time.
“Flows of matter falling into black holes can create some of the brightest events in the universe,” said Chris Nixon, an associate professor of theoretical physics at the University of Leeds and a co-author of the study, in a statement sent. “We still don’t fully understand a lot of things, but there are amazing observational facilities that keep surprising us and giving us new things to learn.” This event is one of those wild cards.
The journal Nature has a paper that talks about the results.
Astronomy
Witness the rare celestial event of Mars and Jupiter reaching their closest proximity in the sky this week, a phenomenon that will not occur again until 2033.
Mars and Jupiter will be only 0.3 degrees apart in the sky on August 14. From our point of view, this passage is very close. If you miss it, you won’t be able to see another one until 2033.
When two objects pass each other in the sky from our point of view, this is called a conjunction. Every time two planets came together, the closer one would block out the other because they would all be moving in a perfectly flat plane. The orbits of the planets are slightly different from those of the other planets, though, so they move slightly to the north and south of each other. Every time, that gap is a different size.
When two things happen close together, the results are especially stunning. Jupiter and Saturn were close enough to each other in 2020 that they could be seen in the same field of view through a telescope. This is a treat for people who like to observe the sky.
Being 0.5 degrees wide, the full moon will fit in any view that can hold the whole moon. This pair will also look good before and after the full moon.
But even with the naked eye, a close conjunction can make the sky look even more amazing. The contrast between the red of Mars and the white of Jupiter will be especially striking. However, Mars’ brightness changes a lot. When it’s at its brightest, it’s about the same brightness as Jupiter. Right now, it’s 16 times less bright. They are so bright that, unless there are clouds, you should be able to see them from all but the dirtiest cities.
Most people in the world will miss this sight, though, because they can’t see the pair of planets in the evening from anywhere on Earth. The exact time they rise depends on where you live, but it’s usually between midnight and 3 am. To see this, you will mostly need to get up before astronomical twilight starts so that you have time to get through the thickest part of the atmosphere.
For people in Europe, Africa, west Asia, and the Americas, the closest time will be 14:53 UTC, which is during the day. The mornings before and after, though, will look almost as close.
Mars and Jupiter meet about every two and a half years, but the most recent one was almost twice as far away and could only be seen in the morning. In 2029, the gaps will be just under two degrees. The next one will be even wider, at more than a degree.
When planets are close to each other, that doesn’t always mean that their distance from each other is very small. Mars has been around the Sun for 687 days, but it is now less than 100 days past its perihelion, which means it is closer than usual. Even though Jupiter is a little closer than usual, it’s not really that close. To be as close as possible to each other, Mars has to be at its farthest point, and Jupiter has to be at its closest point. So this one is not unusual.
But if you want to see something beautiful, you will have to wait more than nine years to see it again.
Space Exploration
World’s first implantation of a titanium heart harnessing maglev technology
When looking for alien civilizations, it can be hard to know what to look for. During the search, we have mostly looked for signals and signs that we would send out (either on purpose or by accident) because we think that aliens will use similar technology since they can use the same physics.
It makes sense to do that, but it’s not the best thing to do. As we’ve seen over the last few hundred years on Earth, intelligent societies can quickly get rid of old technology that can be found as they learn more about the universe. As a clear example, we quickly switched from communicating with analog signals to digital ones. Of course, analog signals in the range we used for communication wouldn’t work very well on alien planets. However, it’s possible that alien civilizations could go “radio quiet” in about 100 years, which would make it even harder to find them.
Scientists have thought about what kind of signal a more advanced civilization might send and how advanced the technology would have to be in order to send it.
Even though it’s just a guess, we have some ideas about what kind of signal would make sense and what the message should say to make it clear that it comes from a smart being.
At that time, the plan was to study a region around 1.42 GHz, which is a well-known frequency where neutral hydrogen gives off radiation in interstellar space. Bryan Brzycki, a graduate student in astronomy at UC Berkeley, told Universe Today more about this. “Because this natural emission is common in the galaxy, it is thought that any intelligent civilization would know about it and might choose to send signals at this frequency to increase their chances of being found.” In the years since then, radio SETI has grown in every way, especially as technology has quickly improved.
Transmitting signals across the galaxy or universe, especially persistent signals that would maximize our likelihood of being detected, necessitates a substantial amount of energy, surpassing the capabilities of human beings. In 1963, Soviet astronomer Nikolai Kardashev endeavored to quantify the magnitude of energy required for transmitting signals containing information, as well as the corresponding levels of technological development that civilizations would need to achieve in order to accomplish this.
Kardashev categorized these theoretical civilizations into three classifications, depending on their capacity to exploit energy from their environment.
Type I civilizations are those that possess the capability to fully utilize the total energy resources of their planet, estimated to be approximately 4 x 1019 erg per second, for their own objectives. Type II civilizations possess the capability to exploit the energy emitted by their star, such as through the construction of Dyson Spheres. These are hypothetical colossal structures specifically designed to enclose stars and harness their energy. Type III civilizations refer to extraterrestrial civilizations that possess the ability to utilize the energy resources of their entire galaxy.
Despite the fact that Type II and III civilizations have significantly high energy production levels, Kardashev estimated that humanity would take approximately 3,200 and 5,800 years to reach those levels, based on Earth’s annual energy production growth rate of 1 percent. In 2020, a comprehensive scale was proposed that introduces the concept of a Type IV civilization capable of harnessing the energy of the entire observable universe. Based on our energy consumption, this team asserts that humans are presently classified as a Type 0.72 civilization.
According to Kardashev, it is highly improbable to detect Type I civilizations due to their relatively small but significantly greater energy output compared to our own. However, a Type I civilization, similar to ours, could potentially detect signals emitted by Type II and Type III civilizations using conventional radio telescopes, although they would not be able to respond to them. The premise of the work is that extraterrestrial civilizations would be transmitting scientific knowledge well ahead of our own, with the purpose of being detected by less advanced civilizations. However, this strategy may not be advisable for any civilization that seeks to ensure its survival.
Nevertheless, the Kardashev scale provides insight into the types of civilizations that possess the ability to transmit signals that we may soon have the capacity to detect. If advanced civilizations indeed exist (considering the immense expanse of the universe and its prolonged existence, this supposition is plausible), it would provide us with additional avenues of exploration, such as the search for colossal megastructures employed for energy extraction.
While we possess a relatively accurate understanding of our current and potential abilities, the universe has been in existence for significantly longer durations. Examining the capabilities of an advanced extraterrestrial civilization can provide insights into our own potential future possibilities. If our search of the celestial realm yields no evidence of Type III civilizations capable of harnessing energy on a galactic scale—a phenomenon that has yet to occur—it could indicate the existence of an obstacle that prevents intelligent species from attaining such an advanced stage. This obstacle, known as the Great Filter, may be looming in our future.
Physics
An interest They stepped on a rock and found something on Mars that had never been seen before
NASA’s curiosity has been looking into an interesting part of Mount Sharp for the past 10 months. It shows signs of a violent watery past, and chemical tests have shown that it contains many minerals, such as sulfates. The rover also broke open a rock by accident as it moved around. And inside it were crystals of pure sulfur.
On Mars, people had never seen pure sulfur before. Even though sulfates contain sulfur, there isn’t a clear link between how those molecules form and how the pure crystals form. Crystals of elemental sulfur can only form in a few different situations. And none of those were thought to happen in this area.
To find a field of stones made of pure sulfur is like finding an oasis in the middle of the desert, said Ashwin Vasavada, the project scientist for Curiosity at NASA’s Jet Propulsion Laboratory. “That thing shouldn’t be there, so we need to explain it.” It’s so exciting to find strange and unexpected things when exploring other planets.
The Gediz Vallis channel is the name of the area that Curiosity is exploring. A groove across Mount Sharp has been interesting for a long time, even before the rover started climbing it in 2014. From space, scientists could see that there were big piles of debris. But it wasn’t clear what caused them. Was it landslides or floodwaters from a long time ago that moved the stuff along the channel?
The answer has been found through curiosity. Some column A and some column B. Water-moved rocks are smoother and rounder. Sharp and angular are those that dry avalanches moved. There are both kinds of rocks in the mounds.
“This was not a quiet time on Mars,” said Becky Williams, a scientist from Tucson, Arizona, who works for the Planetary Science Institute and is the deputy principal investigator of Mastcam on Curiosity. “There was a lot of exciting stuff going on here.” We expect a number of different flows to happen down the channel, such as strong floods and flows with lots of rocks.
Curiosity is still looking into the Gediz Valley. When the ball rolls around and shows off its unique features, we can get very excited about the science being done here.
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