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Georgina Steytler on Unsplash

NASA Astronomy Picture of the Day:

What is the sound of two black holes merging in deep space? Sound waves don't propagate in vacuum, but gravitational waves do. In 2015 we were able to "hear" them for the first time and confirm one of Albert Einstein's theoretical predictions. Each square on the grid of the featured image represents one of the gravitational wave detections announced so far by the LIGO-VIRGO-KAGRA Collaboration. These plots show how the binary pair accelerates in their orbit around each other towards merger: the rising frequency effect is called a "chirp". Although there are significantly more neutron stars than black holes, most of the detections are binary black hole mergers. That happens because black holes are heavier and their signals are louder and can be seen farther away, resulting in more detections. These events are rare, and we don't expect to see one close by in our Galaxy any time soon. But they are happening continuously throughout the cosmos.

Kyzylkup table mountain. Kyzylsai regional park, Mangystau District, Mangystau Region, Kazakhstan.

Максат79, CC BY-SA 4.0, via Wikimedia Commons. View source.

But then there comes that moment rare
When, for no cause that I can find,
The little voices of the air
Sound above all the sea and wind.

The sea and wind do then obey
And sighing, sighing double notes
Of double basses, content to play
A droning chord for the little throats—

The little throats that sing and rise
Up into the light with lovely ease
And a kind of magical, sweet surprise
To hear and know themselves for these—

For these little voices: the bee, the fly,
The leaf that taps, the pod that breaks,
The breeze on the grass-tops bending by,
The shrill quick sound that the insect makes.

(Poem is in the Public domain)

Kathleen Mansfield Murry (née Beauchamp; 1888 –1923) was a New Zealand writer, essayist and journalist, considered one
of the most influential and important authors of the modernist movement. Her works are celebrated across the world, and have been published in many languages. Wikipedia

Christopher Burns on Unsplash

"Being out on the edge, with everything at risk, is where you learn and grow the most". - Jim Whittaker

NASA Astronomy Picture of the Day:

In the words of today's astrophotographer, Rositsa Dimitrova, "What have these silent sentinels watched pass across the sky?" The volcanic mo'ai (meaning statue) of Ahu Tongariki stand guard over Rapa Nui (Isla de Pascua, Easter Island), a Polynesian island (annexed by Chile in 1888) located thousands of kilometers off the coast of South America in the Pacific Ocean. Due to the island's remoteness, the mo'ai, with their backs to the dark ocean, are able to gaze upon a clear and vibrant night sky. Pictured, these larger-than-life statues stare at the bright band of the Milky Way, partly obscured by interstellar dust and blurred by Earth's clouds. Under such clear night skies, the Rapa Nui created observatories and used astronomical observations for navigation, calendar calibration, celebrations, and more. Images like this one remind us of the importance of dark skies, protecting the land underneath them, and preserving the culture that they inspire.

Photo by Rositsa Dimitrova Text: Keighley Rockcliffe (NASA GSFC, UMBC CSST, CRESST II)

Villages of Hullathy Gram Panchayat in a steep arid valley in the north face of the Nilgiri Mountains. Villagers have created a vibrant agrarian economy, largely vegetables and tea, using terraces and irrigation. Tamil Nadu, India.

Timothy A. Gonsalves, CC BY-SA 4.0, via Wikimedia Commons. View source.

Caitlin Wynne on Unsplash

NASA Astronomy Picture of the Day:

Is gravity the same over the surface of the Earth? No -- in some places you will feel slightly heavier than others. The featured Earth map video shows in colors and exaggerated highs and lows where the gravitational field of Earth is relatively strong and weak. A low spot, where you would feel slightly lighter, can be seen just off the coast of India, in blue, while a relative high occurs in the mountains of Chile in South America. The cause of these irregularities does not always follow present surface features. Scientists hypothesize that other important factors lie in deep underground structures in Earth's mantle and may be related to the Earth's appearance in the distant past. The featured map was composed from data taken by NASA's twin GRACE satellites that orbited the Earth from 2002 to 2017. GRACE mapped Earth's gravity by carefully tracking tiny changes in the distance between the two satellites.

View NASA’s Astronomy Photo of the Day