NASA Highlights: Astronomical Photos of the Week (7/30 to 8/5/2022)

How about starting the weekend by checking out the latest photos selected by NASA astronomers? Here, you can see the Moon in a different way: in a photo taken during the Apollo 11 mission, our natural satellite appears in an anaglyph, that is, in an image specially edited to be seen with 3D glasses. In another photo, we see the Moon partially covered by clouds in an incredible perspective.

As usual, we also have pictures of a galaxy, nebula and even a beautiful star cluster, which impresses with its brightness. Check out:

Saturday (30) — 3D Eagle Module

Three-dimensional image of the ascent of the Eagle lunar module (Image: Reproduction/Apollo 11, NASA/John Kaufmann (ALSJ))

If you have a pair of 3D glasses at home, with one red and one blue lens, this is a good time to pick it up and check out this three-dimensional photo of lunar orbit. This is an anaglyph, that is, it is a photo that has been edited to have two colored layers superimposed with a small distance between them, giving an effect of depth to the viewer.

The anaglyph in question was created from two photos taken by Michael Collins, who served as a command module pilot on the Apollo 11 mission. He photographed the ascending stage of the Eagle lunar module, with Neil Armstrong and Buzz Aldrin ascending to meet with the command module in lunar orbit, July 21, 1969.

The large dark area on the lunar surface is Mare Smythii, one of the lunar “seas” on the Earth-facing lunar face. The region is named after the English astronomer William Henry Smyth and is circular in shape, probably coming from a large impact. Afterwards, new space rocks bombarded the area, giving rise to its irregular shape.

Sunday (31) — Galaxy M94 through the “eyes” of Hubble

The galaxy Messier 94, about 15 million light-years from us (Image: Reproduction/ESA/Hubble & NASA)

Towards the constellation Canes Venatici, the Hounds of Hunting, is the galaxy Messier 94. Considered a very popular object among astronomers, this galaxy is of the spiral type and extends for 30 thousand light years and has other spiral arms that do not appear here, but go even further into space. In this Hubble telescope photo, we see just 7,000 light-years from the central region of it.

The beauty of the M94 is certainly a spectacle in itself, and it’s even more impressive in this photo, which directs the eye to its compact, shiny core. Around it are the dusty galactic arms marked by the bluish glow of the massive, young stars there, arranged in a sort of ring. These stars appear to be less than 10 million years old.

This indicates that M94 is undergoing an intense star formation process, which may have been caused by a pressure wave traveling outward from its center. This wave compresses the gas and dust in the outermost regions, causing the gaseous matter to collapse into denser clouds; inside them, gravity brings the gas and dust together. When they reach the right pressure and temperature, new stars are born.

Monday (1st) — Dust in the Carina Nebula

Dust pillars in the Carina Nebula (Image: Reproduction/NASA, ESA, Hubble/Javier Pobes)

It may not look like it, but there is a “stellar fight” going on in this image of the Carina Nebula: on one side, we have the stars; on the other, dust. Apparently, the stars are gaining due to the light and winds coming from the youngest of them. Together, these emissions are evaporating and dispersing the stellar nurseries of dust that gave rise to them.

The Carina, the nebula home to these dusty pillars, is a large star-forming region located about 7,500 light-years from Earth. The pillars, on the other hand, are formed mainly by gaseous hydrogen, but have an appearance marked by dark dust. Typically, dust pillars are less dense than air, and they are given a mountain-like appearance because of the opaque interstellar dust.

This photo of the interior of the Carina Nebula was taken by the Hubble Space Telescope, and it shows an area about 3,000 light-years across. In just a few million years, the stars must “beat” the ongoing process; when that happens, the dust mountain should eventually be evaporated.

Tuesday (2) — Moon “clothed” by Saturn

Clouds in front of the Moon (Image: Reproduction/Francisco Sojuel)

At first glance, it may seem that this is a photo of Saturn, but make no mistake: in fact, the image shows the Moon photographed behind some clouds that appeared in the right place at the right time. At dawn when the record was captured, most of the surface of our natural satellite was illuminated by light reflected by the Earth. This light is known as “Earthshine”, in the English term.

As with Earth, the Moon has a “night” and a “day” side, which change as it rotates. That’s why half of the moon is always lit, and how much we can see of this part varies as our natural satellite moves in its orbit. The bright band at the bottom of the Moon shows that it was in the crescent phase.

As sunlight is falling on the lower part of it, this shows that our star was below the horizon. Therefore, the photo was taken during the late dawn, even before the sun rose. The photo was captured on December 24, 2019 in Pacaya, Guatemala, the day before a beautiful solar eclipse fascinated observers at the scene.

Wednesday (3) — Cat’s Eye Nebula

The Cat’s Eye nebula is one of the best known planetary nebulae (Image: Reproduction/Bray Falls)

These colors and shapes make up the Cat’s Eye nebula, one of the most complex planetary nebulae we know. Planetary nebulae are unique objects, formed when Sun-like stars reach the end of their lives and expand their outer layers, becoming red giants.

Afterwards, the star releases its outer layers into space and exposes its core to high temperatures. Its ultraviolet radiation shines on the surrounding gas, causing it to glow — it is this gas that forms the planetary nebula. Over time, it disperses and the star cools, until, one day, it will become a white dwarf.

In the case of this nebula, the photo shows some very symmetrical formations in its central region. However, they are not the highlight of the image, but the outer halo of the image, which spans about three light-years. Recently, astronomers have found some planetary nebulae with large halos, which appear to come from material ejected during earlier stages of the stellar evolution process.

Thursday (4) — The glow of the Great Globular Cluster of Hercules

The Great Globular Cluster in Hercules is one of the brightest in the northern hemisphere sky (Image: Reproduction/Joan Josep Isach Cogollos)

Can you imagine how many stars there are in M31, the globular star cluster that shines in this photo? Well, it’s hard to know the exact amount, but astronomers estimate that there are over 100,000 of them there. M31 is approximately 25,000 light-years from us and is one of the most visible objects of its kind in the northern sky, and can even be observed with binoculars.

M31 was discovered in 1714 by astronomer Edmond Halley, best known for the comet that bears his name. When astronomer Charles Messier added M13 to his catalog in 1764, he was fully convinced that there were no stars there. It’s just that, as the stars are very close together, they could only be observed individually after 1779.

Globular star clusters are formed by groups of stars that are held together by the action of gravity. Typically, these clusters can house from a few tens of thousands of stars to several million of them. They are present in almost all galaxies.

Friday (5th) — The colors of the Trifid Nebula

The Trifid Nebula is towards the constellation Sagittarius (Image: Reproduction / Vikas Chander)

These colors and shapes are part of the Trifid Nebula. Cataloged as “M20”, this star-forming nebula was discovered in 1764 by astronomer Charles Messier. It is located about nine thousand light-years from Earth, towards the constellation Sagittarius and, as it can be observed through small telescopes, it is one of the “darlings” of amateur astronomers.

As the name implies, this nebula is made up of three lobes of glowing gas, separated by lanes of dark dust. At the center of it are massive, bright newborn stars, giving off intense radiation; this radiation helps sculpt the cosmic cloud around the object. An interesting aspect of this photo is that, in it, we can observe different types of nebulae.

In red is an emission nebula dominated by the light of hydrogen atoms. The bluish area is a reflection nebula, born from dust reflecting starlight. Finally, the third type is a dark nebula, which appears in regions where clouds of dark dust draw attention by silhouette, in contrast to the surrounding colors.

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