Perseverance: Seven Minutes to Mars

How hard is it to land safely on Mars? So hard that many more attempts have failed than succeeded. The next attempt will be on Thursday. The main problem is that the Martian atmosphere is too thick to ignore -- or it will melt your spacecraft. On the other hand, the atmosphere is too thin to rely on parachutes -- or your spacecraft will crash land. Therefore, as outlined in the featured video, the Perseverance lander will lose much of its high speed by deploying a huge parachute, but then switch to rockets, and finally, assuming everything goes right, culminate with a hovering Sky Crane that will slowly lower the car-sized Perseverance rover to the surface with ropes. It may sound crazy, but the Curiosity rover was placed on Mars using a similar method in 2012. From atmospheric entry to surface touch-down takes about seven minutes, all coordinated by an onboard computer because Mars is too far away for rapid interactive communication. During this time, humans on Earth will simply wait to hear if the landing was successful. Last week, UAE's Hope spacecraft successfully began orbiting Mars, followed a day later by the Chinese Tianwen-1 mission, which will likely schedule a landing of its own rover sometime in the next few months.

from NASA https://ift.tt/3ddTsv3

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The Galactic Center in Radio from MeerKAT

What's happening at the center of our galaxy? It's hard to tell with optical telescopes since visible light is blocked by intervening interstellar dust. In other bands of light, though, such as radio , the galactic center can be imaged and shows itself to be quite an interesting and active place . The featured picture shows the latest image of our Milky Way's center by the MeerKAT array of 64 radio dishes in South Africa . Spanning four times the angular size of the Moon (2 degrees ), the image is impressively vast, deep, and detailed. Many known sources are shown in clear detail, including many with a prefix of Sgr, since the galactic center is in the direction of the constellation Sagittarius . In our Galaxy's Center lies Sgr A , found here in the image center, which houses the Milky Way's central supermassive black hole. Other sources in the image are not as well understood, including the Arc , just to the left of Sgr A , and numerous filamentary threads....

Why is the sky near Antares and Rho Ophiuchi so colorful, yet dusty? The colors result from a mixture of objects and processes. Fine dust -- illuminated by starlight -- produces blue reflection nebulae . Gaseous clouds whose atoms are excited by ultraviolet starlight produce reddish emission nebulae . Backlit dust clouds block starlight and so appear dark . Antares , a red supergiant and one of the brighter stars in the night sky , lights up the yellow-red clouds on the upper right of the featured image. The Rho Ophiuchi star system lies at the center of the blue reflection nebula on the left, while a different reflection nebula, IC 4605 , lies just below and right of the image center. These star clouds are even more colorful than humans can see, emitting light across the electromagnetic spectrum . from NASA https://ift.tt/fdIYn7J

NGC 1365: Majestic Island Universe

Barred spiral galaxy NGC 1365 is truly a majestic island universe some 200,000 light-years across. Located a mere 60 million light-years away toward the faint but heated constellation Fornax , NGC 1365 is a dominant member of the well-studied Fornax Cluster of galaxies. This sharp color image shows the intense, reddish star forming regions near the ends of the galaxy's central bar and along its spiral arms. Seen in fine detail, obscuring dust lanes cut across the galaxy's bright core. At the core lies a supermassive black hole. Astronomers think NGC 1365's prominent bar plays a crucial role in the galaxy's evolution, drawing gas and dust into a star-forming maelstrom and ultimately feeding material into the central black hole . from NASA https://ift.tt/A0ESVno

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