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By NASA
Skywatching Home What’s Up: December 2024… Skywatching Skywatching Home What’s Up Eclipses Explore the Night Sky Night Sky Network More Tips and Guides FAQ
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Catch December’s Celestial Highlights!
This month, Venus dazzles as the “Evening Star,” Jupiter reaches its brightest for the year, and the Geminid meteor shower peaks under challenging moonlit skies.
Skywatching Highlights
All Month – Planet Visibility:
Mercury: Visible very low in the southeast just before sunrise during the last half of the month. Venus: Shines brightly as the “Evening Star” in the southwest after sunset, climbing higher each evening. Mars: Brightens significantly during December, rising in the east-northeast and visible from late evening to early morning. Jupiter: Reaches opposition on December 7, making it visible all night, rising in the east-northeast. Saturn: Visible after sunset in the southern sky, shifting slightly westward as the month progresses. December 3-5 – Venus and the Moon: Look southwest after sunset to see a beautiful pairing. On December 4, a slim crescent Moon will sit directly below Venus.
December 7 – Jupiter at Opposition: Jupiter will shine at its brightest for the year, rising in the east-northeast among Taurus’s stars. Best viewed through a telescope for details like the Galilean moons and atmospheric belts.
December 14 – Jupiter, the Moon, and Aldebaran: Look for Jupiter midway between the nearly full Moon and bright orange star Aldebaran in the evening sky.
December 17 – Mars and the Moon: Mars, glowing brightly in its approach to opposition, appears super close to the waning gibbous Moon.
All Month – Winter Triangle: Formed by Sirius, Procyon, and Betelgeuse, this asterism marks the arrival of winter skies and is a prominent feature throughout the season.
December 13-14 – Geminid Meteor Shower: The peak occurs under a nearly full Moon, reducing visibility, but bright meteors may still be spotted the week before.
December 21 – Winter Solstice: At 4:20 a.m. EST, the solstice marks the beginning of winter in the Northern Hemisphere and summer in the Southern Hemisphere.
Transcript
What’s Up for December?
Venus, Jupiter, and Mars shine brightly; the stars of winter and their pointy little friend; and “Meteors, meet the Moon.”
Sky chart showing the changing position of Venus after sunset during December. NASA/JPL-Caltech Starting off with the planets, Venus is hard to miss in the southwest after sunset – it’s that dazzling bright “evening star.” You’ll find it getting a bit higher in the sky each evening through the month. On December 4th, look for a slim crescent Moon hanging right below it, making for a great photo opportunity!
Sky chart showing the changing position of Venus after sunset during December. NASA/JPL-Caltech Saturn is visible toward the south beginning at nightfall. Look for it to track a bit farther to the west as the weeks go by. Meanwhile, Jupiter reaches opposition on December 7th, meaning it’s at its brightest for the year and visible all night long. You’ll find it rising in the east-northeast as darkness falls, among the stars of the constellation Taurus. Mid-month, around December 14th, watch for Jupiter sitting between the nearly full Moon and Taurus’s brightest star, orange-colored Aldebaran.
Next, Mars will also be putting on its own show, doubling its brightness during December as it heads toward its own opposition in January. Early in the month, it rises about four hours after dark, but by New Year’s Eve, it’s rising just about 90 minutes after sunset – always shining with its distinctive reddish hue. And on December 17th, you’ll find the Red Planet super close to the Moon, which will be just two days past its full phase.
The stars of winter are making their grand entrance in December. As evening falls, you’ll see the mighty hunter Orion rising in the east, with Taurus the bull above it, and the stars of the twins in Gemini to their left. These constellations host some wonderful sights – like the Crab Nebula and Pleiades star cluster in Taurus and the misty Orion Nebula, which hangs below Orion’s belt. If you look to the western sky soon after dark, you can still spot the three bright stars of the Summer Triangle getting quite low on the horizon. But as they depart, three bright stars of winter bring their own prominent triangular shape to mark the season.
Once you spot Orion’s distinctive belt of three stars, you’re well on your way to finding what we call the Winter Triangle. Just follow the belt stars to the left and slightly downward – they point right to Sirius, the brightest star in the night sky. Then look upward and to the left of Sirius to spot Procyon, and back up toward Orion to find reddish Betelgeuse at its shoulder. These three bright stars form an equilateral triangle that’s visible throughout the season.
The Geminid meteor shower peaks after midnight in the early morning of December 14th, and they’re usually one of the best meteor showers of the year under good conditions. This year, the nearly full Moon will wash out the fainter meteors on the peak night. Still, the Geminids are known for bright meteors, and it’s common to spot their shooting stars up to a week before the peak. If you’re up before dawn that week, it’s worth looking up, just in case you spot a speck of dust from space streaking through the morning sky.
And here are the phases of the Moon for December.
The phases of the Moon for December 2024. NASA/JPL-Caltech Stay up to date on all of NASA’s missions exploring the solar system and beyond at NASA Science.
I’m Preston Dyches from NASA’s Jet Propulsion Laboratory, and that’s What’s Up for this month.
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By NASA
The NASA Ames Science Directorate recognizes the outstanding contributions of (pictured left to right) Forrest Melton, Ariel Deutsch, Dan Sirbu, and Chanel Idos. Their commitment to the NASA mission represents the entrepreneurial spirit, technical expertise, and collaborative disposition needed to explore this world and beyond.
Earth Science Star: Forrest Melton
Forrest Melton serves as Senior Research Scientist with the Atmospheric Science Branch, and leads the OpenET consortium, which develops a unique satellite-driven support system for water resources management using six satellite-driven models and publicly available data from NASA, USGS and NOAA. OpenET currently provides data for 23 states in the western U.S., delivers data at daily, monthly, seasonal and annual timescales, and has become a necessary tool for domestic and international water managers and agricultural producers (feature story).
Space Science & Astrobiology Star: Ariel Deutsch
Ariel Deutsch is an early career planetary scientist in the Planetary Systems Branch for the Bay Area Environmental Research Institute. She is recognized for being invited to join the Artemis II Science Team to support the Artemis II Lunar Science Objectives. Her Lunar Data Analysis Program grant was selected to improve our understanding of the distribution and abundance of volatiles cold-trapped on the Moon, which include Artemis III candidate landing sites.
Space Science & Astrobiology Star: Dan Sirbu
Dan Sirbu is a key member of the Exoplanet Technologies group within the Astrophysics Branch. He currently serves as the principal investigator on the Photonic Integrated Circuit High-Contrast Imaging for Space Astronomy (AstroPIC) early career initiative, serves multiple roles on the Multi-Star Wavefront Control (MSWC) project, and is involved in outreach efforts. In recent months, Dan has been the primary operator performing MSWC testing, setting several new performance records demonstrating high contrast imaging of planets around binary stars. Dan’s work also advances NASA’s and humanity’s capability of imaging exoplanets in multi-star systems, including Alpha Centauri, the nearest star system to the Sun.
Space Biosciences Star: Chanel Idos
Chanel Idos serves as the ARC Resource Analyst for the Human Research Program (HRP) in the Space Biosciences Division. HRP is a multifaceted initiative encompassing six Elements and Offices at JSC and three Divisions across two Directorates at ARC. Her exceptional expertise, coupled with outstanding organizational skills and clear, effective communication, have been instrumental in ensuring the seamless operation of HRP activities at ARC. Chanel’s contributions have been pivotal in achieving excellent cost performance for FY24, positioning ARC to enter FY25 in an optimal state.
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By NASA
Space-grown crystals could lead to targeted cancer drugs
Researchers used space-grown protein crystals to determine the structure of a helix-loop-helix (HLH) peptide (one with a double helix and connecting loop) in a complex with vascular endothelial growth factor-A (VEGF). VEGF prompts the formation of new blood vessels and inhibiting it can stop tumor growth. This finding suggests that HLH peptides could be used to create drugs to target disease-related proteins like VEGF.
JAXA PCG, an investigation from JAXA (Japan Aerospace Exploration Agency), grew protein crystals in microgravity and returned them to Earth for detailed analysis of their structures. Microgravity enables production of high-quality crystals, and examining their structures supports the design of new drugs and other types of research.
Japan Aerospace Exploration Agency astronaut Soichi Noguchi works on the PCG experiment aboard the International Space Station.NASA Wood could make satellites more sustainable
Wood exposed to space for approximately 10 months showed no change in weight and no erosion due to atomic oxygen. This finding could inform selection of the appropriate species and thickness of wood for use in building satellites.
Metal satellites reentering Earth’s atmosphere can generate particles and aerosols that may harm the ozone layer. Wood becomes water and carbon dioxide on reentry, does not contribute to atmospheric pollution, and could provide a more sustainable option for future space exploration. JAXA’s Exposure of Wood to Outer Space evaluated how atomic oxygen, galactic cosmic rays, and solar energetic particles in space affect the mechanical properties of wood.
Different types of wood to be tested in space as a building material for satellites. Kyoto University Analyzing glass-forming ability of magnesium silicates
Researchers report detailed structural and atomic information for glassy and liquid magnesium silicates, which are important in glass science and geoscience. The results suggest that electronic structure does not play an important role in determining glass-forming ability, but atomic structure does.
JAXA’s Fragility measured thermophysical properties such as density and viscosity of oxidized molten metals using the International Space Station’s Electrostatic Levitation Furnace (ELF) to gain insight into glass formation and the design of novel materials. The ELF makes it possible to observe the behavior of materials without the use of a container, providing information crucial for examining glass formation.
NASA astronaut Scott Kelly works on the Electrostatic Levitation Furnace aboard the International Space Station.NASAView the full article
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By NASA
8 min read
Preparations for Next Moonwalk Simulations Underway (and Underwater)
Return to 2024 SARP Closeout Faculty Advisors:
Dr. Tom Bell, Woods Hole Oceanographic Institution
Dr. Kelsey Bisson, NASA Headquarters Science Mission Directorate
Graduate Mentor:
Kelby Kramer, Massachusetts Institute of Technology
Kelby Kramer, Graduate Mentor
Kelby Kramer, graduate mentor for the 2024 SARP Ocean Remote Sensing group, provides an introduction for each of the group members and shares behind-the scenes moments from the internship.
Lucas DiSilvestro
Shallow Water Benthic Cover Type Classification using Hyperspectral Imagery in Kaneohe Bay, Oahu, Hawaii
Lucas DiSilvestro
Quantifying the changing structure and extent of benthic coral communities is essential for informing restoration efforts and identifying stressed regions of coral. Accurate classification of shallow-water benthic coral communities requires high spectral and spatial resolution, currently not available on spaceborne sensors, to observe the seafloor through an optically complex seawater column. Here we create a shallow water benthic cover type map of Kaneohe Bay, Oahu, Hawaii using the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) without requiring in-situ data as inputs. We first run the AVIRIS data through a semi-analytical inversion model to derive color dissolved organic matter, chlorophyll concentration, bottom albedo, suspended sediment, and depth parameters for each pixel, which are then matched to a Hydrolight simulated water column. Pure reflectance for coral, algae, and sand are then projected through each water column to create spectral endmembers for each pixel. Multiple Endmember Spectral Mixture Analysis (MESMA) provides fractional cover of each benthic class on a per-pixel basis. We demonstrate the efficacy of using simulated water columns to create surface reflectance spectral endmembers as Hydrolight-derived in-situ endmember spectra strongly match AVIRIS surface reflectance for corresponding locations (average R = 0.96). This study highlights the capabilities of using medium-fine resolution hyperspectral imagery to identify fractional cover type of localized coral communities and lays the groundwork for future spaceborne hyperspectral monitoring of global coral communities.
Atticus Cummings
Quantifying Uncertainty In Kelp Canopy Remote Sensing Using the Harmonized Landsat Sentinel-2 Dataset
Atticus Cummings
California’s giant kelp forests serve as a major foundation for the region’s rich marine biodiversity and provide recreational and economic value to the State of California. With the rising frequency of marine heatwaves and extreme weather onset by climate change, it has become increasingly important to study these vital ecosystems. Kelp forests are highly dynamic, changing across several timescales; seasonally due to nutrient concentrations, waves, and predator populations, weekly with typical growth and decay, and hourly with the tides and currents. Previous remote sensing of kelp canopies has relied on Landsat imagery taken with a eight-day interval, limiting the ability to quantify more rapid changes. This project aims to address uncertainty in kelp canopy detection using the Harmonized Landsat and Sentinel-2 (HLS) dataset’s zero to five-day revisit period. A random forest classifier was used to identify pixels that contain kelp, on which Multiple Endmember Spectral Mixture Analysis (MESMA) was then run to quantify intrapixel kelp density. Processed multispectral satellite images taken within 3 days of one another were paired for comparison. The relationship between fluctuations in kelp canopy density with tides and currents was assessed using in situ data from an acoustic doppler current profiler (ADCP) at the Santa Barbara Long Term Ecological Research site (LTER) and a NOAA tidal buoy. Preliminary results show that current and tidal trends cannot be accurately correlated with canopy detection due to other sources of error. We found that under cloud-free conditions, canopy detection between paired images varied on average by 42%. Standardized image processing suggests that this uncertainty is not created within the image processing step, but likely arises due to exterior factors such as sensor signal noise, atmospheric conditions, and sea state. Ultimately, these errors could lead to misinterpretation of remotely sensed kelp ecosystems, highlighting the need for further research to identify and account for uncertainties in remote sensing of kelp canopies.
Jasmine Sirvent
Kelp Us!: A Methods Analysis for Predicting Kelp Pigment Concentrations from Hyperspectral Reflectance
Jasmine Sirvent
Ocean color remote sensing enables researchers to assess the quantity and physiology of life in the ocean, which is imperative to understanding ecosystem health and formulating accurate predictions. However, without proper methods to analyze hyperspectral data, correlations between spectral reflectance and physiological traits cannot be accurately derived. In this study, I explored different methods—single variable regression, partial least squares regressions (PLSR), and derivatives—in analyzing in situ Macrocystis pyrifera (giant kelp) off the coast of Santa Barbara, California in order to predict pigment concentrations from AVIRIS hyperspectral reflectance. With derivatives as a spectral diagnostic tool, there is evidence suggesting high versus low pigment concentrations could be diagnosed; however, the fluctuations were within 10 nm of resolution, thus AVIRIS would be unable to reliably detect them. Exploring a different method, I plotted in situ pigment measurements — chlorophyll a, fucoxanthin, and the ratio of fucoxanthin to chlorophyll a—against hyperspectral reflectance that was resampled to AVIRIS bands. PLSR proved to be a more successful model because of its hyperdimensional analysis capabilities in accounting for multiple wavelength bands, reaching R2 values of 0.67. Using this information, I constructed a model that predicts kelp pigments from simulated AVIRIS reflectance using a spatial time series of laboratory spectral measurements and photosynthetic pigment concentrations. These results have implications, not only for kelp, but many other photosynthetic organisms detectable by hyperspectral airborne or satellite sensors. With these findings, airborne optical data could possibly predict a plethora of other biogeochemical traits. Potentially, this research would permit scientists to acquire data analogous to in situ measurements about floating matters that cannot financially and pragmatically be accessed by anything other than a remote sensor.
Isabelle Cobb
Correlations Between SSHa and Chl-a Concentrations in the Northern South China Sea
Isabelle Cobb
Sea surface height anomalies (SSHa)–variations in sea surface height from climatological averages–occur on seasonal timescales due to coastal upwelling and El Niño-Southern Oscillation (ENSO) cycles. These anomalies are heightened when upwelling plumes bring cold, nutrient-rich water to the surface, and are particularly strong along continental shelves in the Northern South China Sea (NSCS). This linkage between SSHa and nutrient availability has interesting implications for changing chlorophyll-a (chl-a) concentrations, a prominent indicator of phytoplankton biomass that is essential to the health of marine ecosystems. Here, we evaluate the long-term (15 years) relationship between SSHa and chl-a, in both satellite remote sensing data and in situ measurements. Level 3 SSHa data from Jason 1/2/3 satellites and chl-a data from MODIS Aqua were acquired and binned to monthly resolution. We found a significant inverse correlation between SSHa and chl-a during upwelling months in both the remote sensing (Spearman’s R=-0.57) and in situ data, with higher resolution in situ data from ORAS4 (an assimilation of buoy observations from 2003-2017) showing stronger correlations (Spearman’s R=-0.75). In addition, the data reveal that the magnitude of SSH increases with time during instances of high correlation, possibly indicating a trend of increased SSH associated with reduced seasonal chl-a concentrations. Thus, this relationship may inform future work predicting nutrient availability and threats to marine ecosystems as climate change continues to affect coastal sea surface heights.
Alyssa Tou
Exploring Coastal Sea Surface Temperature Anomalies and their effect on Coastal Fog through analyzing Plant Phenology
Alyssa Tou
Marine heat waves (MHW) have been increasing in frequency, duration and intensity, giving them substantial potential to influence ecosystems. Do these MHWs sufficiently enhance coastal precipitation such that plant growth is impacted? Recently, the Northeast Pacific experienced a long, intense MHW in 2014/2015, and another short, less intense MHW in 2019/2020. Here we investigate how the intensity and duration of MHWs influence the intensity and seasonal cycle of three different land cover types (‘grass’, ‘trees’, and a combination of both ‘combined’’) to analyze plant phenology trends in Big Sur, California. We hypothesize that longer intense MHWs decrease the ocean’s evaporative capacity, decreasing fog, thus lowering plant productivity, as measured by Normalized Difference Vegetation Index (NDVI). Sea surface temperature (SST) and NDVI data were collected from the NOAA Coral Reef Watch, and NASA MODIS/Terra Vegetation Indices 16-Day L3 Global 250m products respectively. Preliminary results show no correlation (R2=0.02) between SSTa and combined NDVI values and no correlation (R2=0.01) between SST and NDVI. This suggests that years with anomalously high SST do not significantly impact plant phenology. During the intense and long 2014/2015 MHW, peak NDVI values for ‘grass’ and ‘combined’ pixels were 2.0 and 1.7 standard deviations above the climatological average, while the shorter 2019/2020 MHW saw higher peaks of 3.2 and 2.4 standard deviations. However, the ‘grass’, ‘tree’ and ‘combined’ NDVI anomalies were statistically insignificant during both MHWs, showing that although NDVI appeared to increase during the shorter and less intense MHW, these values may be attributed to other factors. The data qualitatively suggest that MHW’s don’t impact the peak NDVI date, but more data at higher temporal resolution are necessary. Further research will involve analyzing fog indices and exploring confounding variables impacting NDVI, such as plant physiology, anthropogenic disturbance, and wildfires. In addition, it’s important to understand to what extent changes in NDVI are attributed to the driving factors of MHWs or the MHWs themselves. Ultimately, mechanistically understanding the impacts MHW intensity and duration have on terrestrial ecosystems will better inform coastal community resilience.
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