Αστρονομική Εικόνα της Ημέρας από τη NASA

Προηγούμενες Αστρονομικές Εικόνες της Ημέρας από τη NASA

The Belt of Venus over Mount Everest

26/06/2023

You've surely seen it, but you might not have noticed it. During a cloudless twilight, just before sunrise or after sunset, part of the atmosphere above the horizon appears slightly dark and off-color. Called the Belt of Venus, this transitional band between the dark eclipsed sky and the bright day sky can be seen most prominently in the direction opposite the Sun. Straight above, blue sky is normal sunlight reflecting off the atmosphere, while near the horizon the clear sky can appear more orange or red. In the Belt of Venus, the atmosphere reflects more light from the setting (or rising) Sun and so appears more red. Featured here, the Belt of Venus was photographed over several Himalayan mountains including, second from the right, Mount Everest, the tallest mountain on Earth. Although usually not mentioned, the belt is frequently caught by accident in other photographs.

Lightning on Jupiter

25/06/2023

Does lightning occur only on Earth? No. Spacecraft in our Solar System have detected lightning on other planets, including Mars, Jupiter and Saturn, and lightning is likely on Venus, Uranus, and Neptune. Lightning is a sudden rush of electrically charged particles from one location to another. On Earth, drafts of colliding ice and water droplets usually create lightning-generating charge separation, but what happens on Jupiter? Images and data from NASA's Jupiter-orbiting Juno spacecraft bolster previous speculation that Jovian lightning is also created in clouds containing water and ice. In the featured Juno photograph, an optical flash was captured in a large cloud vortex near Jupiter's north pole. During the next few months, Juno will perform several close sweeps over Jupiter's night side, likely allowing the robotic probe to capture more data and images of Jovian lightning.

3D Ingenuity

24/06/2023

The multicolor, stereo imaging Mastcam-Z on the Perseverance rover zoomed in to capture this 3D close-up (get out your red/blue glasses) of the Mars Ingenuity helicopter on mission sol 45. That's Earth-date 2021 April 5. Casting a shadow on the Martian surface, Ingenuity is standing alone on its four landing legs next to the rover's wheel tracks. The experimental helicopter's solar panel, charging batteries that keep it warm through the cold Martian nights and power its flight, sits just above Ingenuity's two 1.2 meter (4 foot) long counter-rotating blades. Thirteen sols later, on April 19, Ingenuity became the first aircraft to perform powered, controlled flight on another planet. It has since gone on to complete more than 50 flights through the thin atmosphere of Mars.

Giant Galaxies in Pavo

23/06/2023

Over 500,000 light years across, NGC 6872 (top right) is a truly enormous barred spiral galaxy, at least 5 times the size of our own very large Milky Way. The appearance of this giant galaxy's distorted and stretched out spiral arms suggests the magnificent wings of a giant bird. Of course its popular moniker is the Condor galaxy. It lies about 200 million light-years distant toward the southern constellation Pavo, the Peacock. Lined with star-forming regions, the distorted spiral arms are due to NGC 6872's gravitational interaction with the nearby smaller galaxy IC 4970, seen just above the giant galaxy's core. The Pavo galaxy group's dominant giant elliptical galaxy, NGC 6876 is below and left of the soaring Condor galaxy.

Stars and Dust across Corona Australis

22/06/2023

Cosmic dust clouds cross a rich field of stars in this telescopic vista near the northern boundary of Corona Australis, the Southern Crown. Part of a sprawling molecular cloud complex this star forming region is a mere 500 light-years away. That's about one third the distance of the more famous stellar nursery known as the Orion Nebula. The 2 degree wide frame would span 15 light-years at the clouds' estimated distance. Mixed with bright nebulosities the dust clouds effectively block light from more distant background stars in the Milky Way and obscure from view embedded stars still in the process of formation. Large dark nebula Bernes 157 is on the left. To its right are a group of pretty reflection nebulae cataloged as NGC 6726, 6727, 6729, and IC 4812. Their characteristic blue color is produced as light from hot stars is reflected by the cosmic dust. The more compact NGC 6729 surrounds young variable star R Coronae Australis. Just below it, filamentary arcs and loops are identified as Herbig Haro objects associated with energetic newborn stars. In fact, at the heart of this area lies the Coronet Cluster, one of the nearest and most active star forming regions.

Three Sun Paths

21/06/2023

Does the Sun follow the same path every day? No. The Sun's path changes during the year, tracing a longer route during the summer than the winter. Pictured here, the Sun's arc was captured from noon to sunset on three days, from highest in the sky to lowest: summer solstice, equinox, and winter solstice. The images were taken near Gatto Corvino Village in Sicily, Italy in 2020 and 2021. The path and time the Sun spends in the sky is more important in determining the season than how close the Earth is to the Sun. In fact, the Earth is closest to the Sun in January, during northern winter. Today is a solstice, so today the Sun is taking its longest path of the year across the sky in Earth's northern hemisphere, but the shortest path in the southern hemisphere.

The Ñandú in the Milky Way

20/06/2023

Have you seen the bird in the Milky Way? Beyond the man in the Moon, the night sky is filled with stories, and cultures throughout history have projected some of their most enduring legends onto the stars and dust above. Generations of people see these celestial icons, hear their associated stories, and pass them down. Pictured here is not only a segment of the central band of our Milky Way galaxy, but, according to folklore of several native peoples of Uruguay, the outline of a great bird called Ñandú. Furthermore, Ñandú's footprint is associated with the Southern Cross asterism. In the foreground, in silhouette, is a statue of María Micaela Guyunusa, an indigenous woman of the Charrúa people who lived in the 1800s and endures as a symbol of colonial resistance. The composite image was taken in mid-April in Cabo Polonio, Uruguay, with the Atlantic Ocean in the background.

The Busy Center of the Lagoon Nebula

19/06/2023

The center of the Lagoon Nebula is a whirlwind of spectacular star formation. Visible near the image center, at least two long funnel-shaped clouds, each roughly half a light-year long, have been formed by extreme stellar winds and intense energetic starlight. A tremendously bright nearby star, Herschel 36, lights the area. Vast walls of dust hide and redden other hot young stars. As energy from these stars pours into the cool dust and gas, large temperature differences in adjoining regions can be created generating shearing winds which may cause the funnels. This picture, spanning about 15 light years, combines images taken in four colors by the orbiting Hubble Space Telescope. The Lagoon Nebula, also known as M8, lies about 5000 light years distant toward the constellation of the Archer (Sagittarius).

Η Αστρονομική Εικόνα της Ημέρας από τη NASA

NGC 3521: Galaxy in a Bubble

19/06/2025