News
Ultra-black Coating Holds Promise for Telescope Applications
If you, like me, have dabbled with telescope making you will know what a fickle friend light can be. On one hand you want to capture as much as you can (but only from the object, not from nearby lights) and want to reflect or refract it to the point of observation or study. What you most certainly don’t want is stray light to be bounced around inside the telescope so components (except the mirror!) are sprayed as black as possible. Unfortunately black paints tend to be quite susceptible to damage and struggle to cope with the harsh conditions and cold temperatures telescopes are subjected to. A team has recently developed a new atomic-layer deposition method which absorbs 99.3% of light and is durable too.
A team of scientists from the University of Shanghai for Science and Technology and the Chinese Academy of Sciences have recently published a paper in the Journal of Vacuum Science and Technology. The paper announces that they have engineered an ultrablack thin-film coating which boasts the remarkable light absorption rate of 99.3%. The technique is tailored for coating aerospace-grade magnesium alloys (not a lot of help for my telescope but there is hope) and the result is a coating that is durable and capable of withstanding harsh environmental conditions.
Of course, this is designed for telescopes operating in the harsh environment of space rather than the cold winter nights of Norfolk in the UK but it will certainly help with professional observatories atop mountains too. Current coatings like vertically aligned carbon nanotubes or black silicon tend to be easily damaged needing repair and leaving contamination that has to be carefully managed.
Another problem is the often difficult and intricate shapes and curves that the black coatings are to be deposited upon. To overcome these problems, the team explored atomic layer deposition (ALD). Items to be coated are paced in a vacuum chamber and exposed to different gases in sequence which will adhere to the object’s surface in thin layers. It’s a technique not too dissimilar to aluminizing a telescope mirror that is placed inside a vacuum chamber before allowing the aluminum to be deposited on the mirror surface.
The vacuum coating method is far easier to apply to intricate shapes than previous techniques. To build up the layers, the process uses alternating layers of aluminum mixed with titanium carbide and silicon nitride. The two materials work well together to stop nearly all light from reflecting off the coated surface.
During the test phase, the team tested wavelengths of light from violet light at 400 nanometers to near-infrared at 1,000 nanometers and found average absorption levels over 99% across all wavelengths. The coating seems to withstand heat, friction, damp, and extreme changes in temperature well so it is most certainly suited to space instrumentation. The team haven’t given up yet though, they are now working to improve the performance of the material.
Source: Ultrablack coating could make next-gen telescopes even better
News
Further Support for Gravitational Wave Background in the Universe
The discovery of the gravitational wave background in 2016 marked a significant milestone in our understanding of the Universe. This groundbreaking discovery was further validated by the release of a second data set from the European Pulsar Timing Array, along with the addition of data from the Indian Pulsar Timing Array. These complementary studies have provided more evidence for the existence of the gravitational wave background, shedding light on the cosmic phenomena that shape our universe.
Gravitational waves are ripples in spacetime that are generated by violent processes such as merging black holes and colliding neutron stars. Predicted by Einstein in 1916 as part of his General Theory of Relativity, these waves have the ability to travel through space, largely unimpeded by any obstacles in their path. The first detection of gravitational waves in 2015 by the Laser Interferometer Gravitational-Wave Observatory (LIGO) confirmed their existence, originating from a gravitational merger between two black holes located 1.3 billion light years away.
The recent confirmation of the gravitational wave background by the European and Indian Pulsar Timing Arrays indicates that we are detecting a combined signal from the mergers of supermassive black holes. This random distribution of gravity waves that permeates the Universe offers a new avenue for studying the cosmos, akin to the Cosmic Background Radiation. The collaborative efforts of various observatories and research institutions have enabled us to delve deeper into the mysteries of the Universe.
Utilizing pulsar timing arrays as galaxy-sized detectors, researchers have been able to monitor and analyze the pulse arrival times of galactic pulsars on Earth. By detecting subtle patterns in these signals, they can uncover the presence of the gravitational wave background. The latest study led by J. Antoniadis from the Institute of Astrophysics in Greece delves into the implications of the low-frequency signals observed in the recent data releases from various pulsar timing array systems.
The accumulation of data from multiple sources has provided undeniable evidence for the existence of the gravitational wave background. With ongoing Pulsar Timing Array projects, the signals of the low-frequency gravity waves will become more distinct, offering a wealth of opportunities to explore the Universe in this novel way. The focus now shifts towards interpreting these signals to unlock the secrets of the cosmos.
-
Entertainment1 week ago
Olivia Munn opens up about her decision to have a full hysterectomy during breast cancer fight: ‘It was the right choice for me’
-
News1 week ago
University of Wisconsin-Milwaukee and Protesters reach an agreement to dismantle encampment
-
Entertainment1 day ago
Simone Biles Emerges Victorious over Suni Lee and Gabby Douglas at Gymnastics Classic
-
News1 day ago
Facing Criticism for Shooting Dog, South Dakota Governor Noem Discusses ‘Difficult Choices’
-
Entertainment11 mins ago
Courteney Cox Reveals Late ‘Friends’ Co-Star Matthew Perry Continues to ‘Visit’ Her Even After His Passing
-
News12 mins ago
Further Support for Gravitational Wave Background in the Universe