Want to watch a solar eclipse safely? Try looking down instead of up, though you might discover you have a plethora of images to choose from. For example, during the June 21st solar eclipse this confusing display appeared under a shady bamboo grove in Pune, India. Small gaps between close knit leaves on the tall plants effectively created a network of randomly placed pinholes. Each one projected a separate image of the eclipsed Sun. The snapshot was taken close to the time of maximum eclipse in Pune when the Moon covered about 60 percent of the Sun’s diameter. But an annular eclipse, the Moon in silhouette completely surrounded by a bright solar disk at maximum, could be seen along a narrow path where the Moon’s dark shadow crossed central Africa, south Asia, and China.
On June 21 an annular solar eclipse came soon after the solstice and our fair planet’s northernmost sunset for 2020. At maximum eclipse, the New Moon in silhouette created a ring of fire visible along a narrow path at most 85 kilometers wide. The annular eclipse path began in central Africa, crossed south Asia and China, and ended over the Pacific Ocean. But a partial eclipse of the Sun was visible over a much broader region. In Hong Kong, this busy section of Jordan Street looks to the northwest, well-aligned with the track of the near solstice afternoon Sun. The street level view was composited with an eclipse sequence made with a safe solar filter on the camera. For that location the eclipse was partial. The Moon covered about 90 percent of the Sun’s diameter at maximum, seen near the middle of the eclipse sequence.
How could that city be upside-down? The city, Chicago, was actually perfectly right-side up. The long shadows it projected onto nearby Lake Michigan near sunset, however, when seen in reflection, made the buildings appear inverted. This fascinating, puzzling, yet beautiful image was captured by a photographer in 2014 on an airplane on approach to Chicago‘s O’Hare International Airport. The Sun can be seen both above and below the cloud deck, with the latter reflected in the calm lake. As a bonus, if you look really closely — and this is quite a challenge — you can find another airplane in the image, likely also on approach to the same airport.
What if you could see X-rays? The night sky would seem a strange and unfamiliar place. X-rays are about 1,000 times more energetic than visible light photons and are produced by violent explosions and high temperature astronomical environments. Instead of the familiar steady stars, the sky would seem to be filled with exotic stars, active galaxies, and hot supernova remnants. The featured X-ray image captures in unprecedented detail the entire sky in X-rays as seen by the eROSITA telescope onboard Spektr-RG satellite, orbiting around the L2 point of the Sun-Earth system, launched last year. The image shows the plane of our Milky Way galaxy across the center, a diffuse and pervasive X-ray background, the hot interstellar bubble known as the North Polar Spur, sizzling supernova remnants such as Vela, the Cygnus Loop and Cas A, energetic binary stars including Cyg X-1 and Cyg X-2, the LMC galaxy, and the Coma, Virgo, and Fornax clusters of galaxies. This first sky scan by eROSITA located over one million X-ray sources, some of which are not understood and will surely be topics for future research.
What are those dark streaks in this composite image of yesterday’s solar eclipse? They are reversed shadows of mountains at the edge of the Moon. The center image, captured from Xiamen, China, has the Moon’s center directly in front of the Sun’s center. The Moon, though, was too far from the Earth to completely block the entire Sun. Light that streamed around all of the edges of the Moon is called a ring of fire. Images at each end of the sequence show sunlight that streamed through lunar valleys. As the Moon moved further in front of the Sun, left to right, only the higher peaks on the Moon’s perimeter could block sunlight. Therefore, the dark streaks are projected, distorted, reversed, and magnified shadows of mountains at the Moon’s edge. Bright areas are called Bailey’s Beads. Only a narrow swath across Earth’s Eastern Hemisphere was able to see yesterday’s full annular solar eclipse. Next June, though, a narrow swath across Earth’s Northern Hemisphere will be able to see the next annular solar eclipse. A total solar eclipse will be visible at the bottom of the world near the end of this year.
It may look like Earthrise, but it’s actually Venus-set. Just after sunrise two days ago, both the Moon and Venus also rose. But then the Moon overtook Venus. In the featured image sequence centered on the Moon, Venus is shown increasingly angularly close to the Moon. In the famous Earthrise image taken just over 50 years ago, the Earth was captured rising over the edge of the Moon, as seen from the Apollo 8 crew orbiting the Moon. This similar Venus-set image was taken from Earth, of course, specifically Estonia. Venus shows only a thin crescent because last week it passed nearly in front of the Sun, as seen from Earth. The Moon shows only a thin crescent because it will soon be passing directly in front of the Sun, as seen from Earth. Today, in fact, two days after this image was taken, the Moon will create a solar eclipse, with a thin swath across the Earth treated to an annular solar eclipse.
Today’s solstice brings summer to planet Earth’s northern hemisphere. But the northern summer solstice arrived for ringed planet Saturn over three years ago on May 24, 2017. Orbiting the gas giant, Saturn’s moon Titan experiences the Saturnian seasons. Larger than inner planet Mercury, Titan was captured in this Cassini spacecraft image about two weeks after its northern summer began. The near-infrared view finds bright methane clouds drifting through Titan’s dense, hazy atmosphere as seen from a distance of about 507,000 kilometers. Below the clouds, dark hydrocarbon lakes sprawl near its fully illuminated north pole.
Transfusing sunlight through a darkened sky, this beautiful display of noctilucent clouds was captured earlier this week, reflected in calm waters from Nykobing Mors, Denmark. From the edge of space, about 80 kilometers above Earth’s surface, the icy clouds themselves still reflect sunlight, though the Sun is below the horizon as seen from the ground. Usually spotted at high latitudes in summer months the night shining clouds have made an early appearance this year as northern nights grow short. Also known as polar mesopheric clouds they are understood to form as water vapor driven into the cold upper atmosphere condenses on the fine dust particles supplied by disintegrating meteors or volcanic ash. NASA’s AIM mission provides daily projections of noctilucent clouds as seen from space.
This telescopic close-up shows off the central regions of otherwise faint emission nebula IC 410, captured under backyard suburban skies with narrowband filters. It also features two remarkable inhabitants of the cosmic pond of gas and dust. Below and right of center are the tadpoles of IC 410. Partly obscured by foreground dust, the nebula itself surrounds NGC 1893, a young galactic cluster of stars. Formed in the interstellar cloud a mere 4 million years ago, the intensely hot, bright cluster stars energize the glowing gas. Composed of denser cooler gas and dust, the tadpoles are around 10 light-years long and are likely sites of ongoing star formation. Sculpted by stellar winds and radiation their heads are outlined by bright ridges of ionized gas while their tails trail away from the cluster’s central young stars. IC 410 lies some 10,000 light-years away, toward the nebula-rich constellation Auriga.
What role do magnetic fields play in interstellar physics? Analyses of observations by ESA’s Planck satellite of emission by small magnetically-aligned dust grains reveal previously unknown magnetic field structures in our Milky Way Galaxy — as shown by the curvy lines in the featured full-sky image. The dark red shows the plane of the Milky Way, where the concentration of dust is the highest. The huge arches above the plane are likely remnants of past explosive events from our Galaxy’s core, conceptually similar to magnetic loop-like structures seen in our Sun’s atmosphere. The curvy streamlines align with interstellar filaments of neutral hydrogen gas and provide tantalizing evidence that magnetic fields may supplement gravity in not only in shaping the interstellar medium, but in forming stars. How magnetism affected our Galaxy’s evolution will likely remain a topic of research for years to come.