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NASA Astronomy Picture of the Day:

Big, bright, beautiful spiral, Messier 106 dominates this cosmic vista. The nearly two degree wide telescopic field of view looks toward the well-trained constellation Canes Venatici, near the handle of the Big Dipper. Also known as NGC 4258, M106 is about 80,000 light-years across and 23.5 million light-years away, the largest member of the Canes II galaxy group. For a far far away galaxy, the distance to M106 is well-known in part because it can be directly measured by tracking this galaxy's remarkable maser, or microwave laser emission. Very rare but naturally occurring, the maser emission is produced by water molecules in molecular clouds orbiting its active galactic nucleus. Another prominent spiral galaxy on the scene, viewed nearly edge-on, is NGC 4217 below and right of M106. The distance to NGC 4217 is much less well-known, estimated to be about 60 million light-years, but the bright spiky stars are in the foreground, well inside our own Milky Way galaxy. Even the existence of galaxies beyond the Milky Way was questioned 100 years ago in astronomy's Great Debate. Experts Debate: How will humanity first discover extraterrestrial life?

Photo by Joonhwa Lee

The Moon is full,
all silver and bright
on this early morning,
before first light.

NASA Astronomy Picture of the Day:

The most distant object easily visible to the unaided eye is M31, the great Andromeda Galaxy some two and a half million light-years away. But without a telescope, even this immense spiral galaxy - spanning over 200,000 light years - appears as a faint, nebulous cloud in the constellation Andromeda. In contrast, a bright yellow nucleus, dark winding dust lanes, expansive blue spiral arms and star clusters are recorded in this stunning telescopic image. While even casual skygazers are now inspired by the knowledge that there are many distant galaxies like M31, astronomers debated this fundamental concept 100 years ago. Were these "spiral nebulae" simply outlying components of our own Milky Way Galaxy or were they instead "island universes", distant systems of stars comparable to the Milky Way itself? This question was central to the famous Shapley-Curtis debate of 1920, which was later resolved by observations of M31 in favor of Andromeda, island universe. Experts Debate: How will humanity first discover extraterrestrial life?

Photo by Yuzhe Xiao

NASA Astronomy Picture of the Day:

Newly discovered Comet SWAN has already developed an impressive tail. The comet came in from the outer Solar System and has just passed inside the orbit of the Earth. Officially designated C/2020 F8 (SWAN), this outgassing interplanetary iceberg will pass its closest to the Earth on May 13, and closest to the Sun on May 27. The comet was first noticed in late March by an astronomy enthusiast looking through images taken by NASA's Sun-orbiting SOHO spacecraft, and is named for this spacecraft's Solar Wind Anisotropies (SWAN) camera. The featured image, taken from the dark skies in Namibia in mid-April, captured Comet SWAN's green-glowing coma and unexpectedly long, detailed, and blue ion-tail. Although the brightness of comets are notoriously hard to predict, some models have Comet SWAN becoming bright enough to see with the unaided eye during June. Experts Debate: How will humanity first discover extraterrestrial life?

Photo by Gerald Rhemann

A feeling of pressure,
building inside,
where my emotions
are trying to hide.
Should I seek help,
Or simply decide
and ask for forgiveness
with you at my side?

NASA Astronomy Picture of the Day:

Do other stars have planetary systems like our own? Yes -- one such system is Kepler-90. Cataloged by the Kepler satellite that operated from Earth orbit between 2009 and 2018, eight planets were discovered, giving Kepler-90 the same number of known planets as our Solar System. Similarities between Kepler-90 and our system include a G-type star comparable to our Sun, rocky planets comparable to our Earth, and large planets comparable in size to Jupiter and Saturn. Differences include that all of the known Kepler-90 planets orbit relatively close in -- closer than Earth's orbit around the Sun -- making them possibly too hot to harbor life. However, observations over longer time periods may discover cooler planets farther out. Kepler-90 lies about 2,500 light years away, and at magnitude 14 is visible with a medium-sized telescope toward the constellation of the Dragon (Draco). The exoplanet-finding mission TESS was launched in 2018, while missions with exoplanet finding capability planned for launch in the next decade include NASA's JWST and WFIRST. Experts Debate: How will humanity first discover extraterrestrial life?

NASA Astronomy Picture of the Day:

How will humanity first learn of extraterrestrial life? One possibility is to find it under the icy surface of Saturn's moon Enceladus. A reason to think that life may exist there are long features -- dubbed tiger stripes -- that are known to be spewing ice from the moon's icy interior into space. These surface cracks create clouds of fine ice particles over the moon's South Pole and create Saturn's mysterious E-ring. Evidence for this has come from the robot Cassini spacecraft that orbited Saturn from 2004 to 2017. Pictured here, a high resolution image of Enceladus is shown from a close flyby. The unusual surface tiger stripes are shown in false-color blue. Why Enceladus is active remains a mystery, as the neighboring moon Mimas, approximately the same size, appears quite dead. A recent analysis of ejected ice grains has yielded evidence that complex organic molecules exist inside Enceladus. These large carbon-rich molecules bolster -- but do not prove -- that oceans under Enceladus' surface could contain life. Another Solar System moon that might contain underground life is Europa. Experts Debate: How will humanity first discover ET life?

NASA Astronomy Picture of the Day:

How big is our universe? This very question, among others, was debated by two leading astronomers 100 years ago today in what has become known as astronomy's Great Debate. Many astronomers then believed that our Milky Way Galaxy was the entire universe. Many others, though, believed that our galaxy was just one of many. In the Great Debate, each argument was detailed, but no consensus was reached. The answer came over three years later with the detected variation of single spot in the Andromeda Nebula, as shown on the original glass discovery plate digitally reproduced here. When Edwin Hubble compared images, he noticed that this spot varied, and so wrote "VAR!" on the plate. The best explanation, Hubble knew, was that this spot was the image of a variable star that was very far away. So M31 was really the Andromeda Galaxy -- a galaxy possibly similar to our own. The featured image may not be pretty, but the variable spot on it opened a door through which humanity gazed knowingly, for the first time, into a surprisingly vast cosmos. Centennial Celebration: Astronomy's Great Debate was 100 Years Ago Today

Photo by Carnegie Institution for Science

Why do I keep buying sketch pads?
A good question, I've said to me,
for I do not have the time
to draw figures or things
having the satisfaction, which it brings.
Don't give up; a talent is there.
In the beginning, I'm told your art
will be fair, as you progress,
after your fresh start.
Appreciate your part.

NASA Astronomy Picture of the Day:

These bright ridges of interstellar gas and dust are bathed in energetic starlight. With its sea of young stars, the massive star-forming region NGC 2014 has been dubbed the Cosmic Reef. Drifting just off shore, the smaller NGC 2020, is an expansive blue-hued structure erupting from a single central Wolf-Rayet star, 200,000 times brighter than the Sun. The cosmic frame spans some 600 light-years within the Large Magellanic Cloud 160,000 light-years away, a satellite galaxy of our Milky Way. A magnificent Hubble Space Telescope portrait, the image was released this week as part of a celebration to mark Hubble's 30th year exploring the Universe from Earth orbit.