After a decade of failed attempts, scientists successfully bounced photons off of a reflector aboard the Lunar Reconnaissance Orbiter, some 240,000 miles from Earth.
Category: space – Page 473
FSO communication systems are where free space acts as a communication channel between transceivers that are line-of-sight (LOS) for successful transmission of optical signals. The channel can be atmosphere, space, or vacuum, whose characteristics determine the transmission and reception of optical signals for designing reliable and efficient communication systems. Using FSO technology data is transmitted by propagation of light through atmospheric or space communication channels, allowing optical connectivity. FSO communication offers a high data rate to meet the tremendous increasing demand of broadband traffic mostly driven by Internet access and HDTV broadcasting services. Compared to fiber optics technology, FSO offers much more flexibility in designing optical network architectures at very high speeds, at tens and hundreds of Gbit/s rates. However, FSO communication is affected by atmospheric effects, which limits sensitivity and achievable data rates with acceptable BER. Some of these degradations are turbulence, absorption, and scattering, and various mitigation techniques exist for reliable and efficient data transmission [1] and to increase the communication performance. Both point-to-point, point-to-multipoint, multipoint-to-point, and multipoint-to-multipoint FSO communications are possible, depending on the different scenarios of establishing optical links. FSO communication is the most practical alternative to solve the bottleneck broadband connectivity problem. The data rates provided by FSO links continue to increase in both long-and short-range applications. FSO will be one of the most unique and powerful tools to address connectivity bottlenecks that have been created in high-speed networks during the past decade due to the tremendous success and continued acceptance of the Internet. The next generation of Internet connectivity will push the limits of existing infrastructure with high-bandwidth applications such as videoconferencing, streaming multimedia content, and network-enabled portable devices. Clearing these bottlenecks is crucial for the future growth and success of the contemporary Internet society. The bandwidth of optical communications access and edge networks will be needed to satisfy these demands. Communication systems are concerned with the transmission of information from a source to a user. The purpose of a communication system is therefore to transfer information. A very basic block diagram of any communication system (optical or radiofrequency (RF)) is shown in Fig. 4.1.
Fig. 4.1 shows a single point-to-point system, whereas in a multiplexed system there may be multiple input and output message sources and users (also called destinations). Fig. 4.2 shows other possible configurations and links for multipoint connections.
OWC is the next frontier for high-speed broadband connection and offers the following unique features and advantages: high bandwidth/capacity, ease of deployment, compact size, low power, and improved channel security. OWC can transmit and exchange voice and video communication data through the atmosphere/free-space at the rates of tens of Gbit/s and much more.
The mysterious dimming of a famous, bright star may have been solved.
Betelgeuse has intrigued astronomers with its “Great Dimming,” but the most famous star in Orion may have generated the event in a massive cosmic burp.
Universal law always works perfectly well.
Wherever there is sand and an atmosphere, prevailing winds may whip the grains into undulating shapes, pleasing to the eye with their calming repetition.
Certain sand waves, with wavelengths between 30 centimeters (almost 12 inches) and several meters (around 30 feet), are known as megaripples: they’re between ordinary beach ripples and full dunes in size, and we’ve seen them not just on Earth, but even on other planets such as Mars, well known for its all-encompassing dust storms.
Aside from their size, a key characteristic of these middle-ground ripples is the grain size involved – a surface of coarse grains over an interior of much finer material. Yet this mix of grains is never the same, and nor are the winds that blow across the sand to create the ripples in the first place.
Over the last thirty years, over 4,000 planets around stars other than the Sun, otherwise known as exoplanets, have been discovered by astronomers but only two exomoons. This is because usually planets are larger and therefore more easily identifiable.
The first exomoon candidate, which the same team of astronomers said was roughly the size of Neptune, was found in 2018 but has yet to be confirmed.
“Our results could give us a new perspective on the evolution of the Earth’s dynamics,” said Motohiko Murakami, a corresponding author of the study explained in a press statement. “They suggest that Earth, like the other rocky planets Mercury and Mars, is cooling and becoming inactive much faster than expected.”
The Earth will cool down at an increasingly fast pace
The scientists discovered that bridgmanite was roughly 1.5 times better at conducting heat than previously estimated. This means that heat must transfer more easily from the core to the mantle than had been previously believed. This faster transfer equals a higher cooling rate, meaning the Earth’s core will cool down faster than once thought. What’s more, as it cools bridgmanite turns into a mineral called post-perovskite, which conducts heat at an even faster rate. So the inner Earth could start to cool at an increasingly accelerated rate once bridgmanite starts forming into post-perovskite, a crystal structure following the formula ABX₃.
Its aim is to help us understand the past and future of the universe.
You may have heard of the Dark Energy Spectroscopic Instrument (DESI) from the Lawrence Berkeley National Laboratory’s Department of Energy. We reported on the project all the way back in 2016 when the team of scientists launched 5,000 small robots into space to help develop the first map of the universe beyond earth.
Then, in 2017, we reported how the project had created a 3D map of our galaxy’s space dust. The map was successful at plotting each individual dust that exists in our galaxy in order to clear up the deep space view and measure the accelerating expansion rate of the universe.
Now, DESI has revealed that it has finally created the largest and most detailed map of the universe ever. As impressive as this achievement is, DESI notes that it’s only 10% done with its five-year mission.
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There a spacecraft so far away in space it has become the first humanmade object to reach interstellar space. It is traveling out there among the stars, far from Earth, far from home. Voyager 1 is set to never return to our star system, let alone Earth. Its mission; to explore the most distant reaches of space.
September 5, 2020, marked 43 since NASA’s Voyager 1 spacecraft launched from Cape Canaveral. In 2012, the probe became the first object to enter an uncharted, never-before-seen region of space; interstellar space. More precisely, on August 25, 2012, at 122 astronomical units, the probe left the so-called heliopause, and so became the first to reach interstellar space.
Although it has made history and has nothing left to prove, the 722 kg robotic probe is still operational today, continuing its extended mission of locating and studying the limits of the solar system, including the Kuiper belt and beyond, as well as exploring immediate interstellar space, until one day, it runs out of fuel and waves back to Earth, one more time.
NASA had a big 2021 and finally launched the James Webb Telescope. But its 2022 schedule is nothing to sneeze at.