The universe is full of mystery, but few of them are as perplexed as fast radio (FRB). These far-reaching and very energetic radio-frequency flashes were only discovered in 2007 and most of the observations come from non-repetitive sources. This makes it difficult to study the phenomenon in detail. The astronomers knew only a few signals repeated before, but a team of researchers reports the discovery of eight other repeating FRBs it could help us understand what's going on there.
The first recorded FRBs took place in 2001, but no one spotted them in the data until a review in 2007. As the name suggests, the fast bursts of radio only last one year. millisecond and the signal on Earth is tiny – it looks like a cell phone. call from the moon. However, the sources are incredibly intense to be visible on Earth. Astronomers believe that the FRB releases as much energy in a millisecond as the sun in 80 years.
Although dozens of FRBs have appeared in the data since this first signal, there has been only a handful of repeated sources. The first of them is known as FRB 121102. He was alone until the beginning of this year when astronomers discovered two other repetitive FRBs. The new study (available on the arXiv pre-print service) from McGill University lists eight other repetitive FRBs.
Researchers used the radio telescope from the Canadian hydrogen intensity mapping experiment (above) to search for FRBs. They observed six new FRBs that only repeated once and one that triggered three bursts. The last one has some particularly excited scientists. Currently called FRB 180916.J0158 + 65, this source has released ten fast bursts of radio for four months of observations.
It has been suggested that all BRAs may repeat themselves, but the time between flashes varies greatly. One of the newly identified repeaters will flash every two or three days, but other sources may spill years between two signals. To help solve this mess, the McGill University team compared the new repeaters to non-repetitive FRB signals. They discovered that repeaters and singles had similar "dispersion measures," which describe how the signal stretches when it travels in the universe. However, bursts of repeaters tend to be a few milliseconds longer than singles, and they sometimes release smaller bursts after the main one.
Knowing where the FRBs will occur helps scientists steer the instruments in the right direction to collect as much data as possible. Dominant assumptions suggest FRB mechanisms such as energetic supernovae and magnetized neutron star emissions known as magnetars, but no one knows for sure. With more FRB sources repeated and confirmed, we could finally get closer to an answer.
There are thousands of confirmed exoplanets in the cosmos, and many of them are members of solar systems very different from ours. While missions such as Kepler and Transiting Exoplanet Satellite Survey (TESS) have highlighted more distant worlds, astronomers have been surprised to see how many of them have what's known as "hot Jupiters." ". WASP-121b is the hottest of these gaseous giants in close orbit. Is it hot? It is so hot that heavy metals escape and propel themselves around the star.
WASP-121b made the headlines in 2017 when scientists used Hubble to characterize its stratosphere. It was a first for any exoplanet and it showed that the temperature of the planet increased with the altitude, just like the planets of our solar system. This is a hot Jupiter with 1.2 times the mass of Jupiter himself. It is about 900 light years away from the head of a slightly larger, warmer star than the sun, but it is so close that its year is only 30 Earth days.
Even by the standards of a Jupiter, WASP-121b is absolutely burning. At 4600 degrees Fahrenheit (2500 degrees Celsius), it's 10 times warmer than any other exoplanet ever discovered. Although it is a little more massive than Jupiter, its diameter is almost twice as big, because the intense heat released by the WASP-121 made it swell. Hubble's new observations show what this intense heat represents for the planet.
The downy outer layers of WASP-121b are less subject to gravity than the inner layers, so they fall away from the planet in orbit. In most gas giants – even hot Jupiters – this would be mostly hydrogen and helium. However, Hubble says WASP-121b loses heavy metals like magnesium and iron. Astronomers assume that incredible heat is enough to lift heavy metals from the lower layers of the atmosphere upward, where they can be lost in space.
WASP-121b is too far away to directly image the atmosphere or the trailing metal gases, but Hubble can track the planet as it passes in front of its host star. The changes of light allow them to determine what is happening in the atmosphere of the exoplanet by spectroscopy. The most interesting aspect of the new analysis is perhaps that the infernal heat influences the shape of the planet. So much of the atmosphere is moving away that the planet probably looks a bit like a football.
Scientists hope to learn more about this extreme planet in the future. The future James Webb Space Telescope should be able to characterize its atmosphere even more precisely.
Astronomers have reflected on the nature of our first interstellar visitor since its discovery. "Oumuamua is weird – not only is he out of the stars, but he's also long and cigar-shaped. This has led some to wonder if it was not really an alien spacecraft, but previous studies of 'Oumuamua have suggested that it's just a rock of space. Now, a comprehensive analysis of scientists from the University of Maryland and other institutions has ruined our pleasure once and for all. "Oumuamua is not an extraterrestrial spaceship.
While there was no doubt that there were previously extraterrestrial objects in our solar system, "Oumuamua was the the first we have ever seen. Observers from the Pan-STARRS observatory identified Oumuamua in October 2017, but he was already emerging from the solar system. Its incredible speed and orbital eccentricity meant that it could not come from within the solar system, but it was moving too fast for everyone to catch up and watch it more closely .
Shortly after the discovery, people were jokingly wondering if Oumuamua was an extraterrestrial ship. Even if we do not know, some attempts have been necessary to properly identify the object. The initial hypothesis was that "Oumuamua was to be a comet because it would be easier to eject them from the edges of a solar system. However, scientists could not see a cometary tail (or coma) on 'Oumuamua. After labeling it as an asteroid, further analysis of its trajectory revealed a slight release of gas. Astronomers finally decided that Oumuamua was probably a very old comet.
So, why is not it really an alien spacecraft with a fuel leak or something? The team behind the new study included experts from various fields to create a "global summary" of "Oumuamua." They started with their origins, showing that there are several possible mechanisms by which an object such as "Oumuamua" could end up in interstellar space. His behavior in our solar system, although strange, is also explicable with natural origins. In fact, its trajectory around the sun corresponds to a prediction published by one of the authors of the study six months before the discovery of "Oumuamua."
& # 39; Oumuamua is strange, but the study concludes that there is nothing inexplicable here. It is amusing to conclude that it is an extraterrestrial spaceship, but the evidence does not confirm it. Astronomers hope to have more extraterrestrial visitors in the future. Upcoming instruments, such as the Large Synoptic Geoptic Telescope (LSST), will facilitate the detection of small objects passing through the solar system. If we can find a few dozen extraterrestrial space rocks, we may discover that "Oumuamua is very typical of visitors from beyond the stars.
Humanity is far from being able to colonize with a single star, not to mention the galaxy of the Milky Way. NASA's Jet Propulsion Laboratory (JPL) has launched an exciting challenge for scientists around the world as part of the 10th Global Trajectory Optimization Competition (GTOC X). The teams had to develop a process to colonize the galaxy in the most efficient way possible. It could take a few million yearsbut the simulations show how we could do it.
The contest, by its very nature, is based on many assumptions. Although we have detected thousands of exoplanets, most of them are too big, too hot or too cold for life. We do not have the technology to locate most Earth-like planets. So there is no world we know how to colonize. Therefore, the contest used a collection of 100,000 hypothetical habitable star systems spread around the Milky Way, all of which are identified by their location and trajectory (called ephemeris) in the contest rules. JPL judged the bids based on the number of stars chosen by the team and the energy expended to do so.
All teams must adhere to the same rules. The contest begins in 10,000 years in what JPL calls "zero year". From that moment, teams have 10 million years simulated to launch their colonization efforts from Earth. Everyone must also use the same initial colonization fleet. They start with three motherships, each with 10 colonization modules able to colonize the star systems as the ship passes. The mothership can also make only three course changes at a total speed of 500 kilometers per second. The Earth can also launch two "fast ships" that travel three times faster but can only colonize one star. Each established star can launch up to three decollating ships with an intermediate speed and the ability to colonize another star.
There is no hyper-advanced chain drive technology here. They are generational ships that can take thousands of years to reach their destination. Most bids used fast ships to launch missions to the edge of the galaxy and work inside colonizing ships. Meanwhile, the mother ships headed for the denser stars near the Earth to release all their pods.
The winning solution came from the Chinese National Defense Technology University and the Xi & # 39; s Satellite Control Center. Second place went to Tsinghua Chinese University, and ESA's team of advanced designers (ACT) ranked third. ACT has also posted a video of its solution on YouTube (see above).
JPL discovered that it took about 90 million years for teams to occupy large tracts of the Milky Way. The universe is billions of years old, why other species have not already done it? That's what we call the Fermi paradox, and nobody knows the answer. Maybe the universe teems with life, but traveling between the stars is fundamentally unachievable. Alternatively, there may be few or no advanced civilizations in the universe. It is even possible that extraterrestrials have colonized most of the galaxy, but they are moving away from Earth for an unknown reason. Anyway, these simulations are an interesting piece of the puzzle.
NASA's Curiosity rover has explored the red planet for almost seven years. He spends most of his time analyzing geology and making selfies. However, it also has some instruments capable of detecting any signs of life on Mars. The agency reports that Curiosity has just detected a unusually high concentration of methane, which we associate with biological processes.
Curiosity has an instrument called SAM (Sample Analysis at Mars), a tunable laser spectrometer capable of measuring atmospheric composition. Last week's data showed a methane concentration of 21 parts per billion units of volume (ppbv). This is more than double what NASA could expect to find on a typical Martian day.
The SAM, however, can not tell us what is the origin of this methane. On Earth, many living organisms release methane, including microbial life. This is why the presence of methane is considered a potential indicator of life. This is not the only way to produce methane, however. There are geological processes involving water and some minerals that can also produce methane. However, the detection was high enough for the Curiosity team to wait for more experiments to collect additional data.
Something in the air tonight
I detected the largest amount of methane ever recorded during my mission: about 21 parts per billion by volume. While microbial life can be a source of methane on Earth, methane can also be produced by interaction between rocks and water. https://t.co/CPEpxsspR2 pic.twitter.com/uk2mjV7OeE
– Rover Curiosity (@MarsCuriosity) June 23, 2019
Data from Mars show that methane concentrations vary seasonally, which may suggest the existence of sub-surface methane pockets. These tanks may be old, reflecting past conditions on Mars. Peaks of methane concentration are also common, but the Curiosity team knows very little about what causes them. NASA is currently conducting more tests to see how the methane concentration changes over time. Whatever the discoveries of Curiosity, they will help us better understand the atmosphere of Mars. A lack of methane could be just as interesting as another good reading. Meanwhile, the ExoMars orbiter has detected almost no methane in the atmosphere during a current test.
Although Curiosity can provide us with useful data on methane levels, the future Mars 2020 will take over this work. This robot uses the same overall design as Curiosity but will focus more on astrobiology with a suite of instruments designed to detect biosignatures. He also has more durable wheels This should go even further than Curiosity. This mobile could help us determine if life has ever existed on Mars or if it still exists. March 2020 will be launched next summer and will arrive on March early in 2021.
Astronomers around the world were thrilled in 2016 when the European Southern Observatory announced the discovery of an exoplanet around Proxima Centauri, the closest star to the Earth. The Centauri system contains a few extra stars. Now the very large telescope (VLT) has gotten an upgrade that will help it sweep these other stars to find evidence of exoplanets.
Proxima Centauri is a red dwarf star located 4.2 light-years from Earth. Alpha Centauri consists of two larger stars located about 4.37 light-years from Earth. Centauri A is a little bigger and brighter than the sun, while Centauri B is smaller and colder. While the exoplanet around Proxima Centauri is in the "habitable zone of the star", the red dwarf is very different from ours. Many scientists believe that Proxima Centauri's radiation and solar flares make life impossible on Proxima Centauri. This might not be the case for planets that may exist around Alpha Centauri A and B.
The VLT, a network of four eight-meter telescopes in Chile, already had the ability to observe the universe in mid-infrared wavelengths. He joins the hunt for exoplanets with the addition of an instrument called NEAR (Near Earths in the AlphaCen region) which makes it much more sensitive.
The planets orbiting the stars are theoretically easier to find, but the light of the Centaurs A and B makes the light relatively weak of an invisible planet. NEAR is an infrared coronograph that filters the light of a star, leaving only light from other objects in a solar system. This differs from traditional methods of detecting exoplanets, which rely on the analysis of their gravitational effects on a star or on the obscuration of starlight as the planets pass in front of it. NEAR could capture real images of an exoplanet.
The European Southern Observatory, which operates the VLT, estimates that NEAR will be sensitive enough to detect a small rocky planet about twice the size of the Earth. Most of the exoplanets detected by astronomers are much larger, but Alpha Centauri is a great place to look for smaller ones because they are so close. The navigation will not be fluid until the end. Alpha Centauri is a binary system. We do not know how planetary systems operate around binary stars, or even their existence.
The NEAR system has completed its first campaign of observation earlier this month. Now, it is up to scientists to look at the data to see if they have found traces of exoplanets around the stars.