apod:

2019 January 12

Milky Way Falls
Image Credit & Copyright: Yuri Beletsky (Carnegie Las Campanas Observatory, TWAN)

Explanation: It can be the driest place on planet Earth, but water still flows in Chile’s Atacama desert, high in the mountains. After discovering this small creek with running water, the photographer returned to the site to watch the Milky Way rise in the dark southern skies, calculating the moment when Milky Way and precious flowing water would meet. In the panoramic night skyscape, stars and nebulae immersed in the glow along the Milky Way itself also shared that moment with the Milky Way’s satellite galaxies the Large and Small Magellanic clouds above the horizon at the right. Bright star Beta Centauri is poised at the very top of the waterfall. Above it lies the dark expanse of the Coalsack nebula and the stars of the Southern Cross.

∞ Source: apod.nasa.gov/apod/ap190112.html

apod:

2019 January 15

The Heart and Soul Nebulas
Image Credit & Copyright: Mario Zauner

Explanation: Is the heart and soul of our Galaxy located in Cassiopeia? Possibly not, but that is where two bright emission nebulas nicknamed Heart and Soul can be found. The Heart Nebula, officially dubbed IC 1805 and visible in the featured image on the bottom right, has a shape reminiscent of a classical heart symbol. The Soul Nebula is officially designated IC 1871 and is visible on the upper left. Both nebulas shine brightly in the red light of energized hydrogen. Also shown in this three-color montage is light emitted from sulfur, shown in yellow, and oxygen, shown in blue. Several young open clusters of stars are visible near the nebula centers. Light takes about 6,000 years to reach us from these nebulas, which together span roughly 300 light years. Studies of stars and clusters like those found in the Heart and Soul Nebulas have focused on how massive stars form and how they affect their environment.

∞ Source: apod.nasa.gov/apod/ap190115.html

startswithabang:

5 Things We Still Don’t Know About Black Holes (And 2 We Do) After LIGO

“1.) How small are the lowest-mass black holes?

LIGO has yet to detect any low-amplitude binaries, providing no information about this population.”

Beginning in 2015, the LIGO detectors began to see robust, bona fide signals of gravitational waves. Of the 11 signals detected to date, 10 of them correspond to black hole-black hole mergers. Gravitational wave astronomy has not only opened up a whole new eye on the Universe, it’s opened up a whole new world as far as our understanding of black holes go. With these 10 mergers under our belt, and an upgraded data run expected later this year, it’s time to take stock of what we don’t yet know, and how we hope to get there. 

Here’s where we are today in our understanding of LIGO’s black holes.

nemfrog:

Solar system with planets’ distance from the sun. This Changing World. 1933. 

(via nemfrog)

visitheworld:

Ice cave on Baffin Island / Canada (by Artur Stanisz).

(via thescalex)

startswithabang:

Ask Ethan: Why Can’t Our Telescopes Find Planet X?

“If scientists can use telescopes to hunt planets, galaxies, exoplanets, etc., then why can’t we scan our solar system for the elusive Planet X or other celestial bodies within our home system?”

If you want to find every object in the Universe, all you have to do is survey the entire sky for the faintest possible astronomical entities. If you have enough resolution, enough light-gathering power, and enough sky coverage, you truly could see it all.

But the telescope technology we have is limited, of course. Telescopes come in finite sizes and can only observe a finite portion of the sky for a finite amount of time. Even with the telescopes we have that can see objects tens of billions of light-years away, we still can’t find everything that’s out there.

Oddly enough, this even includes potentially large worlds within our Solar System! Why is that? Find out on this edition of Ask Ethan!

apod:

2019 January 5

Yutu 2 on the Farside
Image Credit: Chinese National Space Administration

Explanation: On January 3, the Chinese Chang'e-4 spacecraft made the first successful landing on the Moon’s farside. Taken by a camera on board the lander, this image is from the landing site inside Von Karman crater. It shows the desksized, six-wheeled Yutu 2 (Jade Rabbit 2) rover as it rolled down lander ramps and across the surface near local sunrise and the start of the two week long lunar day. Ripe for exploration, Von Karman crater itself is 186 kilometers in diameter. It lies within the Moon’s old and deep South Pole-Aitken impact basin with some of the most ancient and least understood lunar terrains. To bridge communications from the normally hidden hemisphere of the Moon, China launched a relay satellite, Queqiao, in May of 2018 in to an orbit beyond the lunar farside.

∞ Source: apod.nasa.gov/apod/ap190105.html

(via oorts-and-clouds)

On this day: 4 January 1797, German astronomer Wilhelm Beer was born. He produced with Johann H Mädler the most accurate large-scale map of the #Moon to date: the Mappa Selenographica. Together with Mädler, they produced their #lunarmap in four volumes between 1834–36. In 1837, they published a description of the Moon, both this and their maps were the most best available for many decades. 

Pic: SJRankin/SLUB Dresden

startswithabang:

The Five Ways The Universe Might End

“4.) Dark energy could transition into another form of energy, rejuvenating the Universe. If dark energy doesn’t decay, but instead remains constant or even strengthens, there’s another possibility that arises. This energy, inherent to the fabric of space today, may not remain in that form forever. Instead, it could get converted into matter-and-radiation, similar to what occurred when cosmic inflation ended and the hot Big Bang began.

If dark energy remains constant until that point, it will create a very, very cold and diffuse version of the hot Big Bang, where only neutrinos and photons can self-create. But if dark energy increases in strength, it could lead to an inflation-like state followed by a new, truly hot Big Bang once again. This is the most straightforward way to rejuvenate the Universe, and create a cyclic-like set of parameters, where the Universe gets another chance to behave like ours did.”

Based on the best knowledge and data that we have today, it’s clear that the Universe isn’t just expansion, but the expansion is accelerating. Does this determine the fate of our Universe unambiguously? If we extrapolate what the data indicates about dark energy into the future, we fully expect that structures (like our local group) that are gravitationally bound today will remain so into the future, but that larger-scale structures which are unbound (like our supercluster, Laniakea) will eventually dissociate. But extrapolation is tricky, and assumes that dark energy doesn’t change over time.

If we allow the possibility of change, though, many more possibilities arise. Here are the five most likely, and how we’ll distinguish between them!

apod:

2019 January 3

Ultima Thule Rotation Gif
Image Credit: NASA, Johns Hopkins University APL, Southwest Research Institute

Explanation: Ultima Thule is the most distant world explored by a spacecraft from Earth. In the dim light 6.5 billion kilometers from the Sun, the New Horizons spacecraft captured these two frames 38 minutes apart as it sped toward the Kuiper belt world on January 1 at 51,000 kilometers per hour. A contact binary, the two lobes of Ultima Thule rotate together once every 15 hours or so. Shown as a blinking gif, the rotation between the frames produces a tantalizing 3D perspective of the most primitive world ever seen. Dubbed separately by the science team Ultima and Thule, the larger lobe Ultima, is about 19 kilometers in diameter. Smaller Thule is 14 kilometers across.

∞ Source: apod.nasa.gov/apod/ap190104.html

everythingfox:

Look at it 😭

(via feigenbaumsworld)