إِلِيزَابِيث الثَّانِية، الِاسمُ الكَامِل إِلِيزَابِيث

“I’m not afraid of death, but I’m in no hurry to die. I have so much I want to do first.”

And he did so much. He became an evershining star for humankind to look up to. Rest in peace.

Time And Space

Silver Fox, emphasis on silver. This is definitely the night time fox.

Photo by Tracy Munson

Ask Ethan: Why don’t comets orbit the same way planets do?

“Why [do] comets orbit the Sun in a parabolic path, unlike planets which orbit in an elliptical one? Where do comets get the energy to travel such a long distance, from the Oort cloud to the Sun & back? Also, how could interstellar comets/asteroids come out of their parent star [system] and visit other ones?”

When we see comets in our Solar System, they can be either periodic, passing near the Sun and then extending very far away, to return many years later, or they could be a one-shot deal. But comets are driven by the same gravitational laws that drive the planets, which simply make fast-moving, nearly-circular ellipses around the Sun. So what makes these orbits so different, particularly if they’re obeying the same laws? Believe it or not, most of the would-be comets out there are moving in exactly the same nearly-circular paths, only they’re far more tenuously held by the Sun. Gravitational interactions might make small changes in their orbits, but if you’re already moving very slowly, a small change can have a very big effect!

Why don’t comets orbit the same way as the planets? Find out on this edition of Ask Ethan!

scenicfever

Autumn leaves at their peak! 🍁 Which tree photo is your favorite, 1-8? 1. @astrailor_jp 2. @arronstruttphotography 3. @pieceofcrop 4. @traveler_sui 5. @dera_e_mon 6. @francoiscasanova 7. @hayate555 8. @rob_visser_photography

Our Weird and Wonderful Galaxy of Black Holes

Black holes are hard to find. Like, really hard to find. They are objects with such strong gravity that light can’t escape them, so we have to rely on clues from their surroundings to find them.

When a star weighing more than 20 times the Sun runs out of fuel, it collapses into a black hole. Scientists estimate that there are tens of millions of these black holes dotted around the Milky Way, but so far we’ve only identified a few dozen. Most of those are found with a star, each circling around the other. Another name for this kind of pair is a binary system.That’s because under the right circumstances material from the star can interact with the black hole, revealing its presence. 

The visualization above shows several of these binary systems found in our Milky Way and its neighboring galaxy. with their relative sizes and orbits to scale. The video even shows each system tilted the way we see it here from our vantage point on Earth. Of course, as our scientists gather more data about these black holes, our understanding of them may change.   

If the star and black hole orbit close enough, the black hole can pull material off of its stellar companion! As the material swirls toward the black hole, it forms a flat ring called an accretion disk. The disk gets very hot and can flare, causing bright bursts of light.

V404 Cygni, depicted above, is a binary system where a star slightly smaller than the Sun orbits a black hole 10 times its mass in just 6.5 days. The black hole distorts the shape of the star and pulls material from its surface. In 2015, V404 Cygni came out of a 25-year slumber, erupting in X-rays that were initially detected by our Swift satellite. In fact, V404 Cygni erupts every couple of decades, perhaps driven by a build-up of material in the outer parts of the accretion disk that eventually rush in. 

In other cases, the black hole’s companion is a giant star with a strong stellar wind. This is like our Sun’s solar wind, but even more powerful. As material rushes out from the companion star, some of it is captured by the black hole’s gravity, forming an accretion disk.

A famous example of a black hole powered by the wind of its companion is Cygnus X-1. In fact, it was the first object to be widely accepted as a black hole! Recent observations estimate that the black hole’s mass could be as much as 20 times that of our Sun. And its stellar companion is no slouch, either. It weighs in at about 40 times the Sun.

We know our galaxy is peppered with black holes of many sizes with an array of stellar partners, but we've only found a small fraction of them so far. Scientists will keep studying the skies to add to our black hole menagerie.

Curious to learn more about black holes? Follow NASA Universe on Twitter and Facebook to keep up with the latest from our scientists and telescopes.

Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com

Amazing Nature Phenomenons

ᴋᴀᴡᴀʜ ɪᴊᴇɴ (ʙʟᴜᴇ ᴠᴏʟᴄᴀɴᴏ) ɪɴᴅᴏɴᴇsɪᴀ

ᴛᴜʀǫᴜᴏɪsᴇ ɪᴄᴇ: ʟᴀᴋᴇ ʙᴀɪᴋᴀʟ-ʀᴜssɪᴀ

sᴜᴘᴇʀᴄᴇʟʟ sᴛᴏʀᴍ

ɢʀᴇᴇɴ ғʟᴀsʜ sᴜɴsᴇᴛ

sɴᴏᴡ ᴄʜɪᴍɴᴇʏ: ᴍᴏᴜɴᴛ ᴇʀʙᴜs-ᴀɴᴛᴀʀᴛɪᴄᴀ

sᴋʏ ᴘᴜɴᴄʜ

sᴛʀɪᴘᴇᴅ ɪᴄᴇʙᴇʀɢs:ᴀɴᴛᴀʀᴛɪᴄᴀ

ʟɪɢʜᴛ ᴘɪʟʟᴀʀs

sᴀʟᴀʀ ᴅᴇ ᴜʏᴜɴɪ (ʀᴇғʟᴇᴄᴛɪɴɢ ᴅᴇsᴇʀᴛ) ʙᴏʟɪᴠɪᴀ

ᴍᴀᴇʟsᴛʀᴏᴍ

ᴇʏᴇ ᴏғ sᴀʜᴀʀᴀ:ᴍᴀᴜʀɪᴛᴀɴɪᴀ

ғɪʀᴇ ʀᴀɪɴʙᴏᴡ

ᴘᴏʀᴏʀᴏᴄᴀ (ɴᴇᴠᴇʀ ᴇɴᴅɪɴɢ ᴡᴀᴠᴇ) ᴀᴍᴀᴢᴏɴ ʀɪᴠᴇʀ-ʙʀᴀᴢɪʟ

ᴀᴜʀᴏʀᴀ ʙᴏʀᴇᴀʟɪs

ɢʀᴇᴀᴛ ʙʟᴜᴇ ʜᴏʟᴇ:ʙᴇʟɪᴢᴇ

ʀᴀɪɴʙᴏᴡ ᴇᴜᴄᴀʟʏᴘᴛᴜs ᴛʀᴇᴇs

sᴛᴏɴᴇ ғᴏʀᴇsᴛ:ᴍᴀᴅᴀɢᴀsᴄᴀʀ

ᴄᴀᴛᴀᴛᴜᴍʙᴏ ʟɪɢʜᴛɴɪɴɢ (ɴᴇᴠᴇʀᴇɴᴅɪɴɢ sᴛᴏʀᴍ) ᴠᴇɴᴇᴢᴜᴇʟᴀ

ᴍᴀᴍᴍᴀᴛᴜs ᴄʟᴏᴜᴅs

ᴡʜɪᴛᴇ ʀᴀɪɴʙᴏᴡ

ᴜɴᴅᴇʀᴡᴀᴛᴇʀ ᴄʀᴏᴘ ᴄɪʀᴄʟᴇs

ʙɪᴏʟᴜᴍɪɴᴇsᴄᴇɴᴛ ᴡᴀᴠᴇs

ᴍᴏʀɴɪɴɢ ɢʟᴏʀʏ ᴄʟᴏᴜᴅs

ᴠᴏʟᴄᴀɴɪᴄ ʟɪɢʜᴛɪɴɢ

ɴᴀᴄʀᴇᴏᴜs ᴄʟᴏᴜᴅs

ʀᴀɪɴʙᴏᴡ ᴍᴏᴜɴᴛᴀɪɴs:ᴄʜɪɴᴀ

ʟᴇɴᴛɪᴄᴜʟᴀʀ ᴄʟᴏᴜᴅ

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