scholarly journals Widespread hematite at high latitudes of the Moon

2020 ◽  
Vol 6 (36) ◽  
pp. eaba1940 ◽  
Author(s):  
Shuai Li ◽  
Paul G. Lucey ◽  
Abigail A. Fraeman ◽  
Andrew R. Poppe ◽  
Vivian Z. Sun ◽  
...  
Keyword(s):  
Ferric Iron ◽  
High Latitudes ◽  
The Moon ◽  
Earth’S Atmosphere ◽  
The Past ◽  
Reducing Conditions ◽  
Moon Mineralogy Mapper ◽  
Earth's Atmosphere ◽  
Iron Bearing ◽  
Isotope Measurements

Hematite (Fe2O3) is a common oxidization product on Earth, Mars, and some asteroids. Although oxidizing processes have been speculated to operate on the lunar surface and form ferric iron–bearing minerals, unambiguous detections of ferric minerals forming under highly reducing conditions on the Moon have remained elusive. Our analyses of the Moon Mineralogy Mapper data show that hematite, a ferric mineral, is present at high latitudes on the Moon, mostly associated with east- and equator-facing sides of topographic highs, and is more prevalent on the nearside than the farside. Oxygen delivered from Earth’s upper atmosphere could be the major oxidant that forms lunar hematite. Hematite at craters of different ages may have preserved the oxygen isotopes of Earth’s atmosphere in the past billions of years. Future oxygen isotope measurements can test our hypothesis and may help reveal the evolution of Earth’s atmosphere.

scholarly journals The Escape of Planetary Atmospheres

1974 ◽  
Vol 65 ◽  
pp. 37-39 ◽  
Author(s):  
Donald H. Menzel
Keyword(s):  
Planetary Atmospheres ◽  
Second Century ◽  
The Moon ◽  
Ancient History ◽  
Earth’S Atmosphere ◽  
The Past ◽  
The Earth ◽  
Earth's Atmosphere

The problem of escape of atmospheres from the Moon and planets has roots deep in ancient history. Many of the great philosophers of the past regarded the Earth's atmosphere as a medium extending to infinity, with a stationary Earth imbedded at the center. Indeed, it was this concept that led Ptolemy, among many others, to conclude that the Earth could not be moving, for otherwise it would be subject to a gale-force wind caused by its own motion. This idea fostered many of the early stories of interplanetary visitations. Lucian, for example, writing in the second century A.D., has his Icarome nippus fly to the Moon and beyond by means of wings attached to his body.

scholarly journals High-resolution spectroscopy and spectropolarimetry of the total lunar eclipse January 2019

2020 ◽  
Vol 635 ◽  
pp. A156
Author(s):  
K. G. Strassmeier ◽  
I. Ilyin ◽  
E. Keles ◽  
M. Mallonn ◽  
A. Järvinen ◽  
...  
Keyword(s):  
Large Scale ◽  
Solar Spectrum ◽  
High Resolution Spectroscopy ◽  
Strong Increase ◽  
Lunar Eclipse ◽  
The Sun ◽  
The Moon ◽  
Earth’S Atmosphere ◽  
The Earth ◽  
Earth's Atmosphere

Context. Observations of the Earthshine off the Moon allow for the unique opportunity to measure the large-scale Earth atmosphere. Another opportunity is realized during a total lunar eclipse which, if seen from the Moon, is like a transit of the Earth in front of the Sun. Aims. We thus aim at transmission spectroscopy of an Earth transit by tracing the solar spectrum during the total lunar eclipse of January 21, 2019. Methods. Time series spectra of the Tycho crater were taken with the Potsdam Echelle Polarimetric and Spectroscopic Instrument (PEPSI) at the Large Binocular Telescope in its polarimetric mode in Stokes IQUV at a spectral resolution of 130 000 (0.06 Å). In particular, the spectra cover the red parts of the optical spectrum between 7419–9067 Å. The spectrograph’s exposure meter was used to obtain a light curve of the lunar eclipse. Results. The brightness of the Moon dimmed by 10.m75 during umbral eclipse. We found both branches of the O2 A-band almost completely saturated as well as a strong increase of H2O absorption during totality. A pseudo O2 emission feature remained at a wavelength of 7618 Å, but it is actually only a residual from different P-branch and R-branch absorptions. It nevertheless traces the eclipse. The deep penumbral spectra show significant excess absorption from the Na I 5890-Å doublet, the Ca II infrared triplet around 8600 Å, and the K I line at 7699 Å in addition to several hyper-fine-structure lines of Mn I and even from Ba II. The detections of the latter two elements are likely due to an untypical solar center-to-limb effect rather than Earth’s atmosphere. The absorption in Ca II and K I remained visible throughout umbral eclipse. Our radial velocities trace a wavelength dependent Rossiter-McLaughlin effect of the Earth eclipsing the Sun as seen from the Tycho crater and thereby confirm earlier observations. A small continuum polarization of the O2 A-band of 0.12% during umbral eclipse was detected at 6.3σ. No line polarization of the O2 A-band, or any other spectral-line feature, is detected outside nor inside eclipse. It places an upper limit of ≈0.2% on the degree of line polarization during transmission through Earth’s atmosphere and magnetosphere.

scholarly journals Restoring the top-of-atmosphere reflectance during solar eclipses: a proof of concept with the UV Absorbing Aerosol Index measured by TROPOMI

2020 ◽  
Author(s):  
Victor Trees ◽  
Ping Wang ◽  
Piet Stammes
Keyword(s):  
Air Quality ◽  
Color Change ◽  
Solar Limb ◽  
Correction Method ◽  
The Moon ◽  
Earth’S Atmosphere ◽  
Earth's Atmosphere ◽  
Solar Eclipses ◽  
Limb Darkening ◽  
Aerosol Index

Abstract. Solar eclipses reduce the measured top-of-atmosphere (TOA) reflectances as derived by Earth observation satellites, because the solar irradiance that is used to compute these reflectances is commonly measured before the start of the eclipse. Consequently, air quality products that are derived from these spectra, such as the ultraviolet (UV) Absorbing Aerosol Index (AAI), are distorted or undefined in the shadow of the Moon. The availability of air quality satellite data in the penumbral and antumbral shadow during solar eclipses, however, may be of particular interest to users studying solar eclipses and their effect on the Earth's atmosphere. Given the time and location of a point on the Earth's surface, we explain how to compute the eclipse obscuration fraction taking into account wavelength dependent solar limb darkening. With the calculated obscuration fractions, we restore the TOA reflectances and the AAI in the penumbral shadow during the annular solar eclipses on 26 December 2019 and 21 June 2020 measured by the TROPOMI/S5P instrument. We verify the calculated obscuration with the observed obscuration using an uneclipsed orbit. In the corrected products, the signature of the Moon shadow disappeared. Not taking into account solar limb darkening, however, would result in a maximum underestimation of the obscuration fraction of 0.06 at 380 nm on 26 December 2019, and in a maximum Moon shadow signature in the AAI of 6.7 points increase. We find that the Moon shadow anomaly in the uncorrected AAI is caused by a reduction of the measured reflectance at 380 nm, rather than a color change of the measured light. We restore common AAI features such as the sunglint and desert dust, and we confirm the restored AAI feature on 21 June 2020 at the Taklamakan desert by measurements of the GOME-2C satellite instrument on the same day but outside the Moon shadow. We conclude that the correction method of this paper can be used to detect real AAI rising phenomena and has the potential to restore any other product that is derived from TOA reflectance spectra. This would resolve the solar eclipse anomalies in satellite air quality measurements in the penumbra and antumbra, and would allow for studying the effect of the eclipse obscuration on the composition of the Earth's atmosphere from space.

scholarly journals Reconciling proxy records and models of Earth's oxygenation during the Neoproterozoic and Palaeozoic

2020 ◽  
Vol 10 (4) ◽  
pp. 20190137 ◽  
Author(s):  
Rosalie Tostevin ◽  
Benjamin J. W. Mills
Keyword(s):  
Continuous Model ◽  
Biogeochemical Model ◽  
Animal Life ◽  
Oxygen Levels ◽  
Earth’S Atmosphere ◽  
The Past ◽  
Proxy Records ◽  
Late Palaeozoic ◽  
Earth's Atmosphere ◽  
Early Palaeozoic

A hypothesized rise in oxygen levels in the Neoproterozoic, dubbed the Neoproterozoic Oxygenation Event, has been repeatedly linked to the origin and rise of animal life. However, a new body of work has emerged over the past decade that questions this narrative. We explore available proxy records of atmospheric and marine oxygenation and, considering the unique systematics of each geochemical system, attempt to reconcile the data. We also present new results from a comprehensive COPSE biogeochemical model that combines several recent additions, to create a continuous model record from 850 to 250 Ma. We conclude that oxygen levels were intermediate across the Ediacaran and early Palaeozoic, and highly dynamic. Stable, modern-like conditions were not reached until the Late Palaeozoic. We therefore propose that the terms Neoproterozoic Oxygenation Window and Palaeozoic Oxygenation Event are more appropriate descriptors of the rise of oxygen in Earth's atmosphere and oceans.

Observational evidence of the meteoritic bombardment

1967 ◽  
Vol 296 (1446) ◽  
pp. 316-319
Keyword(s):  
Surface Layer ◽  
Lunar Surface ◽  
Prima Facie ◽  
Observational Evidence ◽  
The Moon ◽  
Earth’S Atmosphere ◽  
Earth's Atmosphere ◽  
The Impact

Prima facie evidence for the meteoritic bombardment of the Moon is given by the known meteoritic environment of the Earth’s atmosphere. The impact by particles of different sizes and the likely damage to the lunar surface are discussed, reference being made to terrestrial craters and experiments with hypervelocity projectiles. An attempt is made to reconcile the formation and distribution of certain features with the results of meteoritic bombard­ment. In a number of instances the reconciliation is unsatisfactory and it is likely that the cause may be internal. It is pointed out that once a surface layer of dust has been formed, the effect of subsequent impacts by the smaller particles will only very slowly increase the depth.

Lunar Luminescence

1962 ◽  
Vol 14 ◽  
pp. 445-452
Author(s):  
J. F. Grainger ◽  
J. Ring
Keyword(s):  
The Moon ◽  
Earth’S Atmosphere ◽  
Eclipse Observations ◽  
Powerful Approach ◽  
Surface Luminescence ◽  
Earth's Atmosphere ◽  
Line Depth

Photometry Of the penumbra of lunar eclipses over a considerable number of years has shown an excess of light over that which can be reasonably explained as an effect of the Earth's atmosphere. Link [1, 2] introduced the hypothesis of surface luminescence on the Moon and showed that it could account for the eclipse phenomenon. However, it is clear that eclipse observations cannot be used to investigate the detailed spectrum and distribution of the luminescent regions. A more powerful approach was suggested by Link [3] which has subsequently been called the “line depth” method.

scholarly journals III.—Note on the Little b Group of Lines in the Solar Spectrum and the New College Spectroscope

1883 ◽  
Vol 32 (1) ◽  
pp. 37-44
Author(s):  
C. Piazzi Smyth
Keyword(s):  
Solar Spectrum ◽  
The Sun ◽  
The Moon ◽  
Earth’S Atmosphere ◽  
Earth's Atmosphere

Every spectroscopist is perfectly aware that the group of dark Fraunhofer lines in the Solar Spectrum, known as “ little b,” is composed of the biggest, broadest, most colossal lines in all the brighter part of any and every spectrum depending on Sunlight, whether direct from the Sun or reflected from the earth's atmosphere, the Moon, or any of the planets.

Using CUS Words in the NICU

2008 ◽  
Vol 27 (6) ◽  
pp. 423-424 ◽  
Author(s):  
Sherri Lee Simons
Keyword(s):  
Outer Space ◽  
Safety Information ◽  
Cutting Edge ◽  
The Moon ◽  
Earth’S Atmosphere ◽  
Differences Of Opinion ◽  
Earth's Atmosphere ◽  
Science Disciplines

THE NATIONAL AERONAUTICS AND Space Administration (NASA) has been known for having some of the best employees in various engineering and science disciplines over the years. NASA’s collective accomplishments and cutting-edge technology made it possible for humankind to explore the moon and outer space, a feat once thought impossible. Yet, despite all of NASA’s accomplishments, on February 1, 2003, seven astronauts died when the Columbia incinerated on reentry into Earth’s atmosphere. A key contributor to that tragedy was a culture that fostered ineffective communication of critical safety information and stifled professional differences of opinion.1,2

Sign in / Sign up

Export Citation Format

Share Document