Autor: Rafael Bustamante

What makes this storm cloud so colorful? First, the cloud itself is composed of millions of tiny droplets of water and ice. Its bottom is almost completely flat — but this isn’t unusual. Bottom flatness in clouds is generally caused by air temperature dropping as you go up, and that above a specific height, water-saturated air condenses out water droplets. The shape of the cloud middle is caused by a water-droplet-laden column of air being blown upward. Most unusual, though, are the orange and yellow colors. Both colors are caused by the cloud’s water drops reflecting sunlight. The orange color in the cloud’s middle and bottom sections are reflections of a nearly red sunset. In contrast, the yellow color of the cloud’s top results from reflection of light from a not-yet-setting Sun, where some — but less — blue light is being scattered away. Appearing to float above the plains in Texas, the featured impressive image of a dynamic cumulonimbus cloud was captured in 2021 while investigating a tornado. [via NASA] https://ift.tt/3tEFqmP

That’s no moon. On the ground, that’s the Lars Homestead in Tunisia. And that’s not just any galaxy. That’s the central band of our own Milky Way galaxy. Last, that’s not just any meteor. It is a bright fireball likely from last year’s Perseids meteor shower. The featured image composite combines consecutive exposures taken by the same camera from the same location. This year’s Perseids peak during the coming weekend is expected to show the most meteors after the first quarter moon sets, near midnight. To best experience a meteor shower, you should have clear and dark skies, a comfortable seat, and patience. [via NASA] https://ift.tt/Hhzgo8Y

What would it look like to return home from outside our galaxy? Although designed to answer greater questions, data from ESA’s robotic Gaia mission is helping to provide a uniquely modern perspective on humanity’s place in the universe. Gaia orbits the Sun near the Earth and resolves stars’ positions so precisely that it can determine a slight shift from its changing vantage point over the course of a year, a shift that is proportionately smaller for more distant stars — and so determines distance. In the first sequence of the video, an illustration of the Milky Way is shown that soon resolves into a three-dimensional visualization of Gaia star data. A few notable stars are labelled with their common names, while others stars are labelled with numbers from a Gaia catalog. Eventually, the viewer arrives in our stellar neighborhood where many stars were tracked by Gaia, and soon at our home star Sol, the Sun. At the video’s end, the reflective glow of Sol’s third planet becomes visible: Earth. [via NASA] https://ift.tt/yk5IojB

On a road trip up Mount Uludağ in Bursa province, Turkey these motorcyclists found themselves above low clouds and fog in late June. With the bright Sun directly behind them, the view down the side of the great mountain revealed a beautiful, atmospheric glory and fog bow. Known to some as the heiligenschein or the Specter of the Brocken, a glory can also sometimes be seen from airplanes or even high buildings. It often appears to be a dark giant surrounded by a bright halo. Of course the dark giant is just the shadow of the observer (90MB video) cast opposite the Sun. The clouds and fog are composed of very small water droplets, smaller than rain drops, that refract and reflect sunlight to create the glory’s colorful halo and this more extensive fog bow. [via NASA] https://ift.tt/ZYnGbwD

As Mars wanders through Earth’s night, it passes about 5 degrees south of the Pleiades star cluster in this composite astrophoto. The skyview was constructed from a series of images captured over a run of 16 consecutive clear nights beginning on July 12. Mars’ march across the field of view begins at the far right, the planet’s ruddy hue. showing a nice contrast with the blue Pleiades stars. Moving much faster across the sky against the distant stars, the fourth planet from the Sun easily passes seventh planet Uranus, also moving across this field of view. Red planet Mars and the ice giant world were in close conjunction, about 1/2 degree apart, on July 16. Continuing its rapid eastward trek, Mars has now left the sister stars and outer planet behind though, passing north of red giant star Aldebaran. Mars will come within about 1/3 degree of Jupiter in planet Earth’s sky on August 14. [via NASA] https://ift.tt/SWyblHw

A visitor to the inner solar system every 70 years or so Comet 13P/Olbers reached its most recent perihelion, or closest approach to the Sun, on June 30 2024. Now on a return voyage to the distant Oort cloud the Halley-type comet is recorded here sweeping through northern summer night skies over historic Kunetice Castle, Czech Republic. Along with a broad dust tail, and brighter coma, this comet’s long ion tail buffeted by storms and winds from the Sun, is revealed in the composite of tracked exposures for comet and sky, and fixed exposures for foreground landscape recorded on July 28. The comet is about 16 light-minutes beyond the castle and seen against faint background stars below the northern constellation Ursa Major. The hilltop castle dates to the 15th century, while Heinrich Olbers discovered the comet in 1815. Captured here low in northwestern skies just after sunset Comet Olbers, for now, offers skywatchers on planet Earth rewarding telescopic and binocular views. Comet 13P/Olbers next perihelion passage will be in 2094. [via NASA] https://ift.tt/oN9Pytp

What is creating these unusual spots? Light-colored spots on Martian rocks, each surrounded by a dark border, were discovered earlier this month by NASA’s Perseverance Rover currently exploring Mars. Dubbed leopard spots because of their seemingly similarity to markings on famous Earth-bound predators, these curious patterns are being studied with the possibility they were created by ancient Martian life. The pictured spots measure only millimeters across and were discovered on a larger rock named Cheyava Falls. The exciting but unproven speculation is that long ago, microbes generated energy with chemical reactions that turned rock from red to white while leaving a dark ring, like some similarly appearing spots on Earth rocks. Although other non-biological explanations may ultimately prevail, speculation focusing on this potential biological origin is causing much intrigue. [via NASA] https://ift.tt/ReMb5ca

To some, it looks like a penguin. But to people who study the universe, it is an interesting example of two big galaxies interacting. Just a few hundred million years ago, the upper NGC 2936 was likely a normal spiral galaxy: spinning, creating stars, and minding its own business. Then it got too close to the massive elliptical galaxy NGC 2937, below, and took a dive. Together known as Arp 142, they are featured in this new Webbinfrared image, while a visible lightHubble image appears in comparison. NGC 2936 is not only being deflected, but distorted, by this close gravitational interaction. When massive galaxies pass near each other, gas is typically condensed from which new stars form. A young group of stars appears as the nose of the penguin toward the right of the upper galaxy, while in the center of the spiral, bright stars together appear as an eye. Before a billion years, the two galaxies will likely merge into one larger galaxy. [via NASA] https://ift.tt/AIedWr3

What’s happening above Uluru? A United Nations World Heritage Site, Uluru is an extraordinary 350-meter high mountain in central Australia that rises sharply from nearly flat surroundings. Composed of sandstone, Uluru has slowly formed over the past 300 million years as softer rock eroded away. The Uluru region has been a home to humans for over 22,000 years. Recorded last month, the starry sky above Uluru includes the central band of our Milky Way galaxy, complete with complex dark filaments of dust, bright red emissionnebulas, and billions of stars. [via NASA] https://ift.tt/bayHuBN

Sometimes, the surface of our Sun seems to dance. In the middle of 2012, for example, NASA’s Sun-orbiting Solar Dynamic Observatory spacecraft imaged an impressive prominence that seemed to perform a running dive roll like an acrobatic dancer. The dramatic explosion was captured in ultraviolet light in the featured time-lapse video covering about three hours. A looping magnetic field directed the flow of hot plasma on the Sun. The scale of the dancing prominence is huge — the entire Earth would easily fit under the flowing arch of hot gas. A quiescent prominence typically lasts about a month and may erupt in a Coronal Mass Ejection (CME), expelling hot gas into the Solar System. The energy mechanism that creates a solar prominence is still a topic of research. Like in 2012, this year the Sun’s surface is again quite active and features many filaments and prominences. [via NASA] https://ift.tt/NqwjXrC