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By NASA
3 min read
Preparations for Next Moonwalk Simulations Underway (and Underwater)
Communities in coastal areas such as Florida, shown in this 1992 NASA image, are vulnerable to the effects of sea level rise, including high-tide flooding. A new agency-led analysis found a higher-than-expected rate of sea level rise in 2024, which was also the hottest year on record.NASA Last year’s increase was due to an unusual amount of ocean warming, combined with meltwater from land-based ice such as glaciers.
Global sea level rose faster than expected in 2024, mostly because of ocean water expanding as it warms, or thermal expansion. According to a NASA-led analysis, last year’s rate of rise was 0.23 inches (0.59 centimeters) per year, compared to the expected rate of 0.17 inches (0.43 centimeters) per year.
“The rise we saw in 2024 was higher than we expected,” said Josh Willis, a sea level researcher at NASA’s Jet Propulsion Laboratory in Southern California. “Every year is a little bit different, but what’s clear is that the ocean continues to rise, and the rate of rise is getting faster and faster.”
This graph shows global mean sea level (in blue) since 1993 as measured by a series of five satellites. The solid red line indicates the trajectory of this increase, which has more than doubled over the past three decades. The dotted red line projects future sea level rise.NASA/JPL-Caltech In recent years, about two-thirds of sea level rise was from the addition of water from land into the ocean by melting ice sheets and glaciers. About a third came from thermal expansion of seawater. But in 2024, those contributions flipped, with two-thirds of sea level rise coming from thermal expansion.
“With 2024 as the warmest year on record, Earth’s expanding oceans are following suit, reaching their highest levels in three decades,” said Nadya Vinogradova Shiffer, head of physical oceanography programs and the Integrated Earth System Observatory at NASA Headquarters in Washington.
Since the satellite record of ocean height began in 1993, the rate of annual sea level rise has more than doubled. In total, global sea level has gone up by 4 inches (10 centimeters) since 1993.
This long-term record is made possible by an uninterrupted series of ocean-observing satellites starting with TOPEX/Poseidon in 1992. The current ocean-observing satellite in that series, Sentinel-6 Michael Freilich, launched in 2020 and is one of an identical pair of spacecraft that will carry this sea level dataset into its fourth decade. Its twin, the upcoming Sentinel-6B satellite, will continue to measure sea surface height down to a few centimeters for about 90% of the world’s oceans.
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This animation shows the rise in global mean sea level from 1993 to 2024 based on da-ta from five international satellites. The expansion of water as it warms was responsible for the majority of the higher-than-expected rate of rise in 2024.NASA’s Scientific Visualization Studio Mixing It Up
There are several ways in which heat makes its way into the ocean, resulting in the thermal expansion of water. Normally, seawater arranges itself into layers determined by water temperature and density. Warmer water floats on top of and is lighter than cooler water, which is denser. In most places, heat from the surface moves very slowly through these layers down into the deep ocean.
But extremely windy areas of the ocean can agitate the layers enough to result in vertical mixing. Very large currents, like those found in the Southern Ocean, can tilt ocean layers, allowing surface waters to more easily slip down deep.
The massive movement of water during El Niño — in which a large pool of warm water normally located in the western Pacific Ocean sloshes over to the central and eastern Pacific — can also result in vertical movement of heat within the ocean.
Learn more about sea level:
https://sealevel.nasa.gov
News Media Contacts
Jane J. Lee / Andrew Wang
Jet Propulsion Laboratory, Pasadena, Calif.
818-354-0307 / 626-379-6874
jane.j.lee@jpl.nasa.gov / andrew.wang@jpl.nasa.gov
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Last Updated Mar 13, 2025 Related Terms
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By USH
In the depths of the ocean, where countless strange fish and creatures dwell in perpetual darkness, they remain unseen, unless unexpectedly caught. This was the case during an expedition by a Russian deep-sea fisherman, who was stunned when he reeled in a bizarre creature that strikingly resembled an alien’s head.
The eerie catch was made by Roman Fedortsov during an expedition in the northern Pacific Ocean.
The fisherman shared the video of the strange creature with his followers, with viewers comparing the bulbous fish to an extraterrestrial or even Krang, the villain from Teenage Mutant Ninja Turtles.
Fisherman Fedortsov has previously made headlines thanks to other weird and wonderful catches which you can view at Dailymail.
Despite its eerie appearance, the fish was not an alien or a mutant but rather a species known as the smooth lumpsucker, a deep-sea fish recognized for its distinctive, gelatinous look.
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By USH
CCOR-1, a newly activated coronagraph onboard NOAA’s GOES-19 weather satellite, is the first of its kind in geostationary orbit. Positioned deep inside the Moon’s orbit, it offers a perspective unavailable to previous coronagraphs like those on SOHO.
New Moons are typically dark and invisible, but NOAA's CCOR-1 coronagraph just captured one in stunning detail.
In the footage, the Moon appears full, an illusion caused entirely by sunlight reflecting off Earth. The brightness isn’t constant, though. As sunrise progresses over the Western Hemisphere, the increasing Earthshine becomes so intense that some frames are saturated with light.
Credit image/source: https://spaceweather.com/
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By USH
On January 25, 2025, an Oklahoma City man recorded a baffling UFO that he described as a "plasma-filled jellybean." A concerned neighbor also spotted something unusual in the sky and soon, the entire neighborhood gathered outside, to witness the anomaly.
The mysterious object emitted a glow and moved erratically, mesmerizing onlookers. In his recorded footage, Frederick can be heard narrating the event. "I don’t hear anything, and it's moving unpredictably," he noted. "It looks like a jellybean, but the interior appears to be plasma."
Frederick decided to launch his drone for a closer look, but upon attempting to deploy his drone, he encountered unexplained technical failures. "My controller provides voice notifications," he explained. "It repeatedly announced, ‘unable to take off, electromagnetic interference."
After multiple attempts, he finally got the drone airborne, reaching approximately 1,000 feet beneath the UFO. However, just after capturing three images, the drone’s video function failed, and its battery, despite being fully charged, suddenly drained. "It had a 35-minute flight time," Frederick stated. "But right after taking those three pictures, the controller alerted me: ‘low battery, return to home."
Seeking expert insight, Frederick shared his footage and images with University of Oklahoma physics professor Mukremin Kilic. When asked about the sighting, Kilic remarked, "I don’t know what it is" and suggested the object was likely a drone. However, this theory does not explain why Frederick’s own drone experienced interference, raising further questions about the true nature of the UFO.
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By NASA
5 min read
Ultra-low-noise Infrared Detectors for Exoplanet Imaging
A linear-mode avalanche photodiode array in the test dewar. The detector is the dark square in the center. Michael Bottom, University of Hawai’i One of the ultimate goals in astrophysics is the discovery of Earth-like planets that are capable of hosting life. While thousands of planets have been discovered around other stars, the vast majority of these detections have been made via indirect methods, that is, by detecting the effect of the planet on the star’s light, rather than detecting the planet’s light directly. For example, when a planet passes in front of its host star, the brightness of the star decreases slightly.
However, indirect methods do not allow for characterization of the planet itself, including its temperature, pressure, gravity, and atmospheric composition. Planetary atmospheres may include “biosignature” gases like oxygen, water vapor, carbon dioxide, etc., which are known to be key ingredients needed to support life as we know it. As such, direct imaging of a planet and characterization of its atmosphere are key to understanding its potential habitability.
But the technical challenges involved in imaging Earth-like extrasolar planets are extreme. First such planets are detected only by observing light they reflect from their parent star, and so they typically appear fainter than the stars they orbit by factors of about 10 billion. Furthermore, at the cosmic distances involved, the planets appear right next to the stars. A popular expression is that exoplanet imaging is like trying to detect a firefly three feet from a searchlight from a distance of 300 miles.
Tremendous effort has gone into developing starlight suppression technologies to block the bright glare of the star, but detecting the light of the planet is challenging in its own right, as planets are incredibly faint. One way to quantify the faintness of planetary light is to understand the photon flux rate. A photon is an indivisible particle of light, that is, the minimum detectable amount of light. On a sunny day, approximately 10 thousand trillion photons enter your eye every second. The rate of photons entering your eye from an Earth-like exoplanet around a nearby star would be around 10 to 100 per year. Telescopes with large mirrors can help collect as much of this light as possible, but ultra-sensitive detectors are also needed, particularly for infrared light, where the biosignature gases have their strongest effects. Unfortunately, state-of-the-art infrared detectors are far too noisy to detect the low level of light emitted from exoplanets.
With support from NASA’s Astrophysics Division and industrial partners, researchers at the University of Hawai’i are developing a promising detector technology to meet these stringent sensitivity requirements. These detectors, known as avalanche photodiode arrays, are constructed out of the same semiconductor material as conventional infrared sensors. However, these new sensors employ an extra “avalanche” layer that takes the signal from a single photon and multiplies it, much like an avalanche can start with a single snowball and quickly grow it to the size of a boulder. This signal amplification occurs before any noise from the detector is introduced, so the effective noise is proportionally reduced. However, at high avalanche levels, photodiodes start to behave badly, with noise exponentially increasing, which negates any benefits of the signal amplification. Late University of Hawai’i faculty member Donald Hall, who was a key figure in driving technology for infrared astronomy, realized the potential use of avalanche photodiodes for ultra-low-noise infrared astronomy with some modifications to the material properties.
University of Hawai’i team members with cryogenic dewar used to test the sensors. From left to right, Angelu Ramos, Michael Bottom, Shane Jacobson, Charles-Antoine Claveau. Michael Bottom, University of Hawai’i The most recent sensors benefit from a new design including a graded semiconductor bandgap that allows for excellent noise performance at moderate amplification, a mesa pixel geometry to reduce electronic crosstalk, and a read-out integrated circuit to allow for short readout times. “It was actually challenging figuring out just how sensitive these detectors are,” said Michael Bottom, associate professor at the University of Hawai’i and lead of development effort. “Our ‘light-tight’ test chamber, which was designed to evaluate the infrared sensors on the James Webb Space Telescope, was supposed to be completely dark. But when we put these avalanche photodiodes in the chamber, we started seeing light leaks at the level of a photon an hour, which you would never be able to detect using the previous generation of sensors.”
The new designs have a format of one megapixel, more than ten times larger than the previous iteration of sensors, and circuitry that allows for tracking and subtracting any electronic drifts. Additionally, the pixel size and control electronics are such that these new sensors could be drop-in replacements for the most common infrared sensors used on the ground, which would give new capabilities to existing instruments.
Image of the Palomar-2 globular cluster located in the constellation of Auriga, taken with the linear-mode avalanche photodiode arrays, taken from the first on-sky testing of the sensors using the University of Hawai’i’s 2.2 meter telescope. Michael Bottom, University of Hawai’i Last year, the team took the first on-sky images from the detectors, using the University of Hawai’i’s 2.2-meter telescope. “It was impressive to see the avalanche process on sky. When we turned up the gain, we could see more stars appear,” said Guillaume Huber, a graduate student working on the project. “The on-sky demonstration was important to prove the detectors could perform well in an operational environment,” added Michael Bottom.
According to the research team, while the current sensors are a major step forward, the megapixel format is still too small for many science applications, particularly those involving spectroscopy. Further tasks include improving detector uniformity and decreasing persistence. The next generation of sensors will be four times larger, meeting the size requirements for the Habitable Worlds Observatory, NASA’s next envisioned flagship mission, with the goals of imaging and characterizing Earth-like exoplanets.
Project Lead: Dr. Michael Bottom, University of Hawai’i
Sponsoring Organization: NASA Strategic Astrophysics Technology (SAT) Program
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Last Updated Feb 18, 2025 Related Terms
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