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NASA Astronomy Picture of the Day:

Here is what the Earth looks like during a solar eclipse. The shadow of the Moon can be seen darkening part of Earth. This shadow moved across the Earth at nearly 2000 kilometers per hour. Only observers near the center of the dark circle see a total solar eclipse - others see a partial eclipse where only part of the Sun appears blocked by the Moon. This spectacular picture of the 1999 August 11 solar eclipse was one of the last ever taken from the Mir space station. The two bright spots that appear on the upper left are thought to be Jupiter and Saturn. Mir was deorbited in a controlled re-entry in 2001. A new solar eclipse will occur over North America in about two weeks.

Photo by CNES

NASA Astronomy Picture of the Day:

This close-up from the Mars Reconnaissance Orbiter's HiRISE camera shows weathered craters and windblown deposits in southern Acidalia Planitia. A striking shade of blue in standard HiRISE image colors, to the human eye the area would probably look grey or a little reddish. But human eyes have not gazed across this terrain, unless you count the eyes of NASA astronauts in the scifi novel The Martian by Andy Weir. The novel chronicles the adventures of Mark Watney, an astronaut stranded at the fictional Mars mission Ares 3 landing site corresponding to the coordinates of this cropped HiRISE frame. For scale Watney's 6-meter-diameter habitat at the site would be about 1/10th the diameter of the large crater. Of course, the Ares 3 landing coordinates are only about 800 kilometers north of the (real life) Carl Sagan Memorial Station, the 1997 Pathfinder landing site.

NASA Astronomy Picture of the Day:

This popular group leaps into the early evening sky around the March equinox and the northern hemisphere spring. Famous as the Leo Triplet, the three magnificent galaxies found in the prominent constellation Leo gather here in one astronomical field of view. Crowd pleasers when imaged with even modest telescopes, they can be introduced individually as NGC 3628 (left), M66 (bottom right), and M65 (top). All three are large spiral galaxies but tend to look dissimilar, because their galactic disks are tilted at different angles to our line of sight. NGC 3628, also known as the Hamburger Galaxy, is temptingly seen edge-on, with obscuring dust lanes cutting across its puffy galactic plane. The disks of M66 and M65 are both inclined enough to show off their spiral structure. Gravitational interactions between galaxies in the group have left telltale signs, including the tidal tails and warped, inflated disk of NGC 3628 and the drawn out spiral arms of M66. This gorgeous view of the region spans over 1 degree (two full moons) on the sky in a frame that covers over half a million light-years at the trio's estimated distance of 30 million light-years.

Photo by Steve Cannistra

NASA Astronomy Picture of the Day:

Across the heart of the Virgo Galaxy Cluster lies a string of galaxies known as Markarian's Chain. Prominent in Markarian's Chain are these two interacting galaxies, NGC 4438 (left) and NGC 4435 - also known as The Eyes. About 50 million light-years away, the two galaxies appear to be about 100,000 light-years apart in this sharp close-up, but have likely approached to within an estimated 16,000 light-years of each other in their cosmic past. Gravitational tides from the close encounter have ripped away at their stars, gas, and dust. The more massive NGC 4438 managed to hold on to much of the material torn out in the collision, while material from the smaller NGC 4435 was more easily lost. The remarkably deep image of this crowded region of the universe also includes many more distant background galaxies.

Photo by Mike Selby

NASA Astronomy Picture of the Day:

What's that at the end of the road? The Sun. Many towns have roads that run east-west, and on two days each year, the Sun rises and sets right down the middle. Today, in some parts of the world (tomorrow in others), is one of those days: an equinox. Not only is this a day of equal night ("aequus"-"nox") and day time, but also a day when the sun rises precisely to the east and sets due west. Displayed here is a picturesque rural road in Alberta, Canada that runs approximately east-west. The featured image was taken during the September Equinox of 2021, but the geometry remains the same every year. In many cultures, this March equinox is taken to be the first day of a season, typically spring in Earth's northern hemisphere, and autumn in the south. Does your favorite street run east-west? Tonight, at sunset, you can find out with a quick glance.

Photo by Alan Dyer, Amazingsky.com, TWAN

NASA Astronomy Picture of the Day:

A bright comet will be visible during next month's total solar eclipse. This very unusual coincidence occurs because Comet 12P/Pons-Brooks's return to the inner Solar System places it by chance only 25 degrees away from the Sun during Earth's April 8 total solar eclipse. Currently the comet is just on the edge of visibility to the unaided eye, best visible with binoculars in the early evening sky toward the constellation of the Fish (Pisces). Comet Pons-Brooks, though, is putting on quite a show for deep camera images even now. The featured image is a composite of three very specific colors, showing the comet's ever-changing ion tail in light blue, its outer coma in green, and highlights some red-glowing gas around the coma in a spiral. The spiral is thought to be caused by gas being expelled by the slowly rotating nucleus of the giant iceberg comet. Although it is always difficult to predict the future brightness of comets, Comet Pons-Brook has been particularly prone to outbursts, making it even more difficult to predict how bright it will actually be as the Moon moves in front of the Sun on April 8. Total Eclipse Info: 2024 Total Solar Eclipse from NASA

Photo by Jan Erik Vallestad

NASA Astronomy Picture of the Day:

Is this galaxy jumping through a giant ring of stars? Probably not. Although the precise dynamics behind the featured image is yet unclear, what is clear is that the pictured galaxy, NGC 7714, has been stretched and distorted by a recent collision with a neighboring galaxy. This smaller neighbor, NGC 7715, situated off to the left of the frame, is thought to have charged right through NGC 7714. Observations indicate that the golden ring pictured is composed of millions of older Sun-like stars that are likely co-moving with the interior bluer stars. In contrast, the bright center of NGC 7714 appears to be undergoing a burst of new star formation. The featured image was captured by the Hubble Space Telescope. NGC 7714 is located about 130 million light years away toward the constellation of the Two Fish (Pisces). The interactions between these galaxies likely started about 150 million years ago and should continue for several hundred million years more, after which a single central galaxy may result.

NASA Astronomy Picture of the Day:

The southern winter Milky Way sprawls across this night skyscape. Looking due south, the webcam view was recorded near local midnight on March 11 in dry, dark skies over the central Chilean Atacama desert. Seen below the graceful arc of diffuse starlight are satellite galaxies of the mighty Milky Way, also known as the Large and Small Magellanic clouds. In the foreground is the site of the European Southern Observatory's 40-metre-class Extremely Large Telescope (ELT). Under construction at the 3000 metre summit of Cerro Armazones, the ELT is on track to become planet Earth's biggest Eye on the Sky.

NASA Astronomy Picture of the Day:

Big, beautiful spiral galaxy NGC 1055 is a dominant member of a small galaxy group a mere 60 million light-years away toward the aquatically intimidating constellation Cetus. Seen edge-on, the island universe spans over 100,000 light-years, a little larger than our own Milky Way galaxy. The colorful, spiky stars decorating this cosmic portrait of NGC 1055 are in the foreground, well within the Milky Way. But the telltale pinkish star forming regions are scattered through winding dust lanes along the distant galaxy's thin disk. With a smattering of even more distant background galaxies, the deep image also reveals a boxy halo that extends far above and below the central bulge and disk of NGC 1055. The halo itself is laced with faint, narrow structures, and could represent the mixed and spread out debris from a satellite galaxy disrupted by the larger spiral some 10 billion years ago.

Photo by Dave Doctor

NASA Astronomy Picture of the Day:

What phase of the Moon is 3.14 radians from the Sun? The Full Moon, of course. Even though the Moon might look full for several days, the Moon is truly at its full phase when it is Pi radians (aka 180 degrees) from the Sun in ecliptic longitude. That's opposite the Sun in planet Earth's sky. Rising as the Sun set on March 9, 2020, only an hour or so after the moment of its full phase, this orange tinted and slightly flattened Moon still looked full. It was photographed opposite the setting Sun from Teide National Park on the Canary Island of Tenerife. Also opposite the setting Sun, seen from near the Teide volcano peak about 3,500 meters above sea level, is the mountain's rising triangular shadow extending into Earth's dense atmosphere. Below the distant ridge line on the left are the white telescope domes of Teide Observatory. Again Pi radians from the Sun, on March 25 the Full Moon will dim slightly as it glides through Earth's outer shadow in a penumbral lunar eclipse.

Photo by El Cielo de Canarias

NASA Astronomy Picture of the Day:

A broad expanse of glowing gas and dust presents a bird-like visage to astronomers from planet Earth, suggesting its popular moniker: the Seagull Nebula. This portrait of the cosmic bird covers a 2.5-degree wide swath across the plane of the Milky Way, near the direction of Sirius, alpha star of the constellation of the Big Dog (Canis Major). Of course, the region includes objects with other catalog designations: notably NGC 2327, a compact, dusty emission and reflection nebula with an embedded massive star that forms the bird's head. Likely part of a larger shell structure swept up by successive supernova explosions, the broad Seagull Nebula is cataloged as Sh2-296 and IC 2177. The prominent bluish arc below and right of center is a bow shock from runaway star FN Canis Majoris. Dominated by the reddish glow of atomic hydrogen, this complex of gas and dust clouds with other stars of the Canis Majoris OB1 association spans over 200 light-years at the Seagull Nebula's estimated 3,800 light-year distance. Almost Hyperspace: Random APOD Generator

Photo by Gianni Lacroce

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