NasaBot's Space

Expanding Plume from DART's Impact [apod.nasa.gov]

What happens if you crash a spaceship into an asteroid?

In the case of NASA's DART spaceship and the small asteroid Dimorphos, as happened last week, you get quite a plume.

The goal of the planned impact was planetary protection — to show that the path of an asteroid can be slightly altered, so that, if done right, a big space rock will miss the Earth.

The high brightness of the plume, though, was unexpected by many, and what it means remains a topic of research.

One possibility is that 170-meter wide Dimorphos is primarily a rubble pile asteroid and the collision dispersed some of the rubble in the pile.

The featured time-lapse video covers about 20 minutes and was taken from the Les Makes Observatory on France's Reunion Island, off the southeast coast of southern Africa.

One of many Earth-based observatories following the impact, the initial dot is primarily Dimorphos's larger companion: asteroid Didymos. Most recently, images show that the Didymos - Dimorphos system has developed comet-like tails.

DART Impact on Dimorphos: Notable images submitted to APOD

Visit Page [apod.nasa.gov]

Jupiter's Europa from Spacecraft Juno [apod.nasa.gov]

What mysteries might be solved by peering into this crystal ball?

In this case, the ball is actually a moon of Jupiter, the crystals are ice, and the moon is not only dirty but cracked beyond repair.

Nevertheless, speculation is rampant that oceans exist under Europa's fractured ice-plains that could support life.

Europa, roughly the size of Earth's Moon, is pictured here in an image taken a few days ago when the Jupiter-orbiting robotic spacecraft Juno passed within 325 kilometers of its streaked and shifting surface.

Underground oceans are thought likely because Europa undergoes global flexing due to its changing gravitational attraction with Jupiter during its slightly elliptical orbit, and this flexing heats the interior.

Studying Juno's close-up images may further humanity's understanding not only of Europa and the early Solar System but also of the possibility that life exists elsewhere in the universe.

Lunation Matrix [apod.nasa.gov]

Observe the Moon every night and you'll see its visible sunlit portion gradually change.

In phases progressing from New Moon to Full Moon to New Moon again, a lunar cycle or lunation is completed in about 29.5 days.

Top left to bottom right, this 7x4 matrix of telescopic images captures the range of lunar phases for 28 consecutive nights, from the evening of July 29 to the morning of August 26, following an almost complete lunation.

No image was taken 24 hours or so just after and just before New Moon, when the lunar phase is at best a narrow crescent, close to the Sun and really hard to see.

Finding mostly clear Mediterranean skies required an occasional road trip to complete this lunar cycle project, imaging in early evening for the first half and late evening and early morning for the second half of the lunation.

Since all the images are registered at the same scale you can use this matrix to track the change in the Moon's apparent size during the single lunation.

For extra credit, find the lunar phase that occurred closest to perigee.

Tonight: International Observe the Moon Night

Equinox Sunrise Around the World [apod.nasa.gov]

A planet-wide collaboration resulted in this remarkable array of sunrise photographs taken around the September 2022 equinox.

The images were contributed by 24 photographers, one in each of 24 nautical time zones around the world.

Unlike more complicated civil time zone boundaries, the 24 nautical time zones are simply 15 degree longitude bands corresponding to 1 hour steps that span the globe.

Start at the upper right for the first to experience a sunrise in the nautical time zone corresponding to Coordinated Universal Time (UTC) + 12 hours.

In that time zone, the photographer was located in Christchurch, New Zealand.

Travel to the west by looking down the column and then moving to the column toward the left for later sunrises as the time zone offset in hours from UTC decreases.

Or, you can watch a video of September 2022 equinox sunrises around planet Earth.

DART: Impact on Asteroid Dimorphos [apod.nasa.gov]

Could humanity deflect an asteroid headed for Earth?

Yes.

Deadly impacts from large asteroids have happened before in Earth's past, sometimes causing mass extinctions of life.

To help protect our Earth from some potential future impacts, NASA tested a new planetary defense mechanism yesterday by crashing the robotic Double Asteroid Redirection Test (DART) spacecraft into Dimorphos, a small asteroid spanning about 170-meters across.

As shown in the featured video, the impact was a success.

Ideally, if impacted early enough, even the kick from a small spacecraft can deflect a large asteroid enough to miss the Earth.

In the video, DART is seen in a time-lapse video first passing larger Didymos, on the left, and then approaching the smaller Dimorphos.

Although the video ends abruptly with DART's crash, observations monitoring the changed orbit of Dimorphos — from spacecraft and telescopes around the world — have just begun.

Visit Page [apod.nasa.gov]

September Sunrise Shadows [apod.nasa.gov]

The defining astronomical moment for this September's equinox was on Friday, September 23, 2022 at 01:03 UTC, when the Sun crossed the celestial equator moving south in its yearly journey through planet Earth's sky.

That marked the beginning of fall for our fair planet in the northern hemisphere and spring in the southern hemisphere, when day and night are nearly equal around the globe.

Of course, if you celebrate the astronomical change of seasons by watching a sunrise you can also look for crepuscular rays.

The shadows cast by clouds can have a dramatic appearance in the twilight sky during any sunrise or sunset.

Due to perspective, the parallel shadows will seem to point back to the rising Sun and a place due east on your horizon near the equinox date.

Taken on September 15, this sunrise sea and skyscape captured crepuscular rays in the sky and watery specular reflections from the Mediterranean coast near the village of Petacciato, Italy.

Ringed Ice Giant Neptune [apod.nasa.gov]

Ringed, ice giant Neptune lies near the center of this sharp near-infrared image from the James Webb Space Telescope.

The dim and distant world is the farthest planet from the Sun, about 30 times farther away than planet Earth.

But in the stunning Webb view the planet's dark and ghostly appearance is due to atmospheric methane that absorbs infrared light.

High altitude clouds that reach above most of Neptune's absorbing methane easily stand out in the image though.

Coated with frozen nitrogen, Neptune's largest moon Triton is brighter than Neptune in reflected sunlight and is seen at upper left sporting the Webb's characteristic diffraction spikes.

Including Triton, seven of Neptune's 14 known moons can be identified in the field of view.

Neptune's faint rings are striking in this new space-based planetary portrait.

Details of the complex ring system are seen here for the first time since Neptune was visited by the Voyager 2 spacecraft in August 1989.

Star Forming Region NGC 3582 without Stars [apod.nasa.gov]

What's happening in the Statue of Liberty nebula?

Bright stars and interesting molecules are forming and being liberated.

The complex nebula resides in the star forming region called RCW 57, and besides the iconic monument, to some looks like a flying superhero or a weeping angel.

By digitally removing the stars, this re-assigned color image showcases dense knots of dark interstellar dust, fields of glowing hydrogen gas ionized by these stars, and great loops of gas expelled by dying stars.

A detailed study of NGC 3576, also known as NGC 3582 and NGC 3584, uncovered at least 33 massive stars in the end stages of formation, and the clear presence of the complex carbon molecules known as polycyclic aromatic hydrocarbons (PAHs).

PAHs are thought to be created in the cooling gas of star forming regions, and their development in the Sun's formation nebula five billion years ago may have been an important step in the development of life on Earth.

Your Sky Surprise: What picture did APOD feature on your birthday? (post 1995)

Star Trails and Lightning over the Pyrenees [apod.nasa.gov]

The beauty in this image comes in layers.

On the bottom layer is the picturesque village of Manlleu in Barcelona, Spain.

The six-minute exposure makes car lights into streaks.

The next layer is a mountain — Serra de Bellmunt — of Europe's famous Pyrenees.

Next up is a tremendous lightning storm emanating from a classically-shaped anvil cloud.

The long exposure allowed for the capture of many intricate lightning bolts.

Finally, at the top and furthest in the distance are stars.

Here, the multi-minute exposure made stars into trails.

The trailing effect is caused by the rotation of the Earth, and the curvature of the trails indicates their distance from the north spin pole of the Earth above.

Taken after sunset in early June, the lightning storm soon moved off.

The stars, though, will continue to circle the pole for as long as the Earth spins — surely billions of years into the future.

Star Trails and Lightning over the Pyrenees [apod.nasa.gov]

The beauty in this image comes in layers.

On the bottom layer is the picturesque village of Manlleu in Barcelona, Spain.

The six-minute exposure makes car lights into streaks.

The next layer is a mountain — Serra de Bellmunt — of Europe's famous Pyrenees.

Next up is a tremendous lightning storm emanating from a classically-shaped anvil cloud.

The long exposure allowed for the capture of many intricate lightning bolts.

Finally, at the top and furthest in the distance are stars.

Here, the multi-minute exposure made stars into trails.

The trailing effect is caused by the rotation of the Earth, and the curvature of the trails indicates their distance from the north spin pole of the Earth above.

Taken after sunset in early June, the lightning storm soon moved off.

The stars, though, will continue to circle the poll for as long as the Earth spins — surely billions of years into the future.