[DrCaleb]

ShepherdsDog ShepherdsDog:

That's close enough to alter the paths of asteroids and comets and send them sunward.

.8 light-years means a travel time of around 100,000 years for any objects displaced. Assuming 65,000MPH as the usual travel speed.

It might be why we are seeing so many comets lately. Or it could be just because we are looking more lately.

[Jabberwalker]

So how big across is the solar system? Is the outside of the Oort cloud the outer limit or are there other shells before it is considered t be "interstellar"?

[ShepherdsDog]

http://www.universetoday.com/104486/how ... ar-system/

[Tyler_1]

I have a wee galaxy that I can hold in one hand plus I have a few space keys.

[DrCaleb]

Jabberwalker Jabberwalker:

So how big across is the solar system? Is the outside of the Oort cloud the outer limit or are there other shells before it is considered t be "interstellar"?

Past the Heliosphere is considered the 'outside'. Like Shep's map, the Oort cloud is thought to be at around 1 light year.

So this star and it's planets came in between the Oort cloud and the Heliosphere.

[DrCaleb]

$1:

New Horizons Captures Two Moons of Pluto: Nix and Hydra

Hydra (S/2005 P1) and Nix (S/2005 P2) were detected using the images taken by the Advanced Camera for Surveys on NASA’s Hubble Space Telescope in May, 2005.

Hydra, the outermost known moon of Pluto, has been calculated to have a diameter of between 61 and 167 km.

Nix is about 25 percent fainter than Hydra, so could be a 10 to 15 percent smaller than Hydra, assuming they have the same surface reflectivity.

Hydra orbits Pluto every 38 days at a distance of 64,700 km, while Nix orbits every 25 days at a distance of 48,700 km.

The new long-exposure images from the New Horizons offer best view yet of these two moons.

Pluto’s two other small moons, Styx and Kerberos, are still smaller and too faint to be seen by New Horizons at its current range to Pluto; they will become visible in the months to come.

“It’s thrilling to watch the details of the Pluto system emerge as we close the distance to the spacecraft’s July 14 encounter,” said Dr John Spencer, a scientist with the Southwest Research Institute and New Horizons science team member.

“This first good view of Nix and Hydra marks another major milestone, and a perfect way to celebrate the anniversary of Pluto’s discovery.”

http://www.sci-news.com/space/science-n ... 02513.html

[DrCaleb]

$1:

Astroquizzical: What happens when Betelgeuse explodes?

Question: If Betelgeuse explodes right now, could we see it with naked eye? It is over 400 light years away, so you might think that people would see it long after it actually happens?

Betelgeuse is already one of the brightest stars in the night sky, sitting somewhere around the 8th or 9th brightest star in the night sky. (These lists don’t include the Sun, which is somewhat obviously always the brightest object in the sky.) It sits in the constellation Orion, along with a number of other bright stars, and makes up the left hand shoulder of the warrior. It looks visibly orange in the night sky, and is classified as a red supergiant star, in the later stages of its life. It’s also one of the few stars that’s close enough for us to resolve in more detail than a point source, and the pictures are pretty fun.



If Betelgeuse were to go supernova right now — as in, if you could break physics and travel to the star instantaneously to check on it — you’re absolutely correct to think that it would take us quite a while to notice. Betelgeuse is about 600 light years away from our solar system, so the light traveling from Betelgeuse has about 600 years of travel before it will reach us. If the star had physically exploded in 2015, we wouldn’t spot the light from that explosion until 2615. We’re constantly observing this star (and pretty much everything in the Universe) as it was, a significant period of time ago. This is also why astronomers say that in studying the night sky, we study the past. The more distant the object, the further in the past we observe. 600 light years, in the grand scheme of things, is pretty close; we’re still dealing with our local neighborhood inside our own galaxy.

Supernovae are incredibly bright phenomena. At the brightest point of the explosion, a supernova can outshine the whole galaxy it lives in. A single star has managed to, for a short time, be a brighter source of light than the several billion other stars in its galaxy combined. This is tremendously bright. Supernovae do have a “rising time” of about a week, when the star is increasing in brightness — it stays at its peak brightness for a few days, and then slowly declines into obscurity over a period of a couple of weeks.

But how bright would Betelgeuse specifically be? We can do some math to work this out, making the assumption that Betelgeuse explodes as a Type II supernova. The exact style of supernova is still up for a bit of debate, depending on the exact rotation speed and mass loss of the star over the next hundred thousand years. Regardless of the exact method of its explosion, all the supernovae options for this star have a peak brightness of approximately the same value, so for a quick calculation that’s good enough to determine what we’d see with the naked eye.

https://medium.com/starts-with-a-bang/a ... 8e4673eaed

[DrCaleb]

$1:

Blue Mars sunset captured in NASA video

You don't have to join Mars One and commit to dying on the planet to see a Martian sunset – NASA has released a new video showing what it would look like.

The Vine video posted by NASA earlier this week was recreated from photos taken by the Opportunity rover, which launched in 2003.

Martian sunset, recreated from photos taken by our Mars Opportunity rover. @MarsRovers @NASASolarSystem #SpaceVine https://t.co/V4crLQB21K
— @NASA

It might surprise you to see that while sunsets on Earth are reddish, the sunset on the Red Planet is bluish.

According to NASA, fine dust particles in Mars's thin atmosphere tend to make the planet's sky look reddish normally.

"But the dust also scatters blue light in the forward direction, creating a bluish sky glow near the setting sun," NASA said in a caption for a sunset photo taken by Opportunity's twin, the Spirit rover, in 2005.

In fact, NASA captures sunset images in part to figure out how high into the atmosphere the dust goes and to look for clouds made of dust or ice.

The sun also looks very small because Mars is farther away from the sun than Earth.

However, the twilight glow lasts a lot longer on Mars than it does on Earth – up to two hours after the sun sets.

That's because of all the dust in the atmosphere scattering the light from the side of the planet that's facing the sun.

Want to see a Mars-like sunset on Earth? NASA says it sometimes occurs after volcanic eruptions that scatter dust high into Earth's atmosphere.

http://www.cbc.ca/news/technology/blue- ... -1.2970932

[Tyler_1]

Blue sunsets kind of rule.

[Jabberwalker]

Nitrogen ...

[Gunnair]

Shiny spot on Ceres. Must be the distant rebel base...

[DrCaleb]

That's no moon!

$1:

NASA's Spitzer Telescope Brings 360-Degree View of Galaxy to Our Fingertips

Touring the Milky Way now is as easy as clicking a button with NASA's new zoomable, 360-degree mosaic presented Thursday at the TED 2014 Conference in Vancouver, Canada.

The star-studded panorama of our galaxy is constructed from more than 2 million infrared snapshots taken over the past 10 years by NASA's Spitzer Space Telescope.

"If we actually printed this out, we'd need a billboard as big as the Rose Bowl Stadium to display it," said Robert Hurt, an imaging specialist at NASA's Spitzer Space Science Center in Pasadena, Calif. "Instead, we've created a digital viewer that anyone, even astronomers, can use."

The 20-gigapixel mosaic uses Microsoft's WorldWide Telescope visualization platform. It captures about three percent of our sky, but because it focuses on a band around Earth where the plane of the Milky Way lies, it shows more than half of all the galaxy's stars.

The image, derived primarily from the Galactic Legacy Mid-Plane Survey Extraordinaire project, or GLIMPSE, is online at: http://www.spitzer.caltech.edu/glimpse360

http://www.spitzer.caltech.edu/news/1624

Seriously . . . holy cow! 3% of the sky, but something like 50% of the stars!

[DrCaleb]

$1:

Warp in Space-Time Swallows Pulsar

Astronomers have watched a pulsar some 25,000 light-years from Earth slip from view, swallowed by a warp in the fabric of spacetime. This wacky effect is one more proof of Einstein's general theory of relativity, 100 years after publication.

When a massive star runs out of fuel, it detonates, spitting gas and other debris with unimaginable violence. The supernova explosion is so powerful, that for days, or even weeks, it can outshine its host galaxy, beaming across the local universe. The calm after the storm reveals what's left behind, which might be an extremely dense neutron star, or even a black hole.

And sometimes that neutron star has a magnetic field a million billion times more powerful than the Earth's field. These objects, known as pulsars, "are super fun to study because they're the next thing down from black holes really in terms of density and extreme physics," study co-author Duncan Lorimer, of West Virginia University, told Space.com

These cosmic magnets emit two beams of radiation from their magnetic north and south poles. As they rotate, these beams might regularly sweep across the Earth, causing astronomers to see pulses of radiation just as we see flashes of light from a lighthouse. Most of the time, the pulses are so regular that you could set your watch by them.

But the flashes from pulsar J1906 studied by Lorimer and colleagues are far from constant.

The pulsar is a part of a rare binary system with a companion star thought to be either another neutron star or a white dwarf. Although roughly two-thirds of the stars in our galaxy are in binary systems, when a supernova goes off, it will give any nearby companion a powerful kick, often sending it into space at millions of miles per hour. But every now and then, pulsars manage to hang onto their companions, providing a rare glimpse into an exotic system. You can see a video of pulsar J1906 orbiting its companion here.

http://www.space.com/28730-spacetime-wa ... ulsar.html

[DrCaleb]

$1:

Planets Venus and Uranus in close conjunction

If you have a clear sky at dusk tonight (~7 pm for the centre of the British Isles), I invite you to look low to the west in the constellation of Pisces where three planets are gathered within the same field of view of a typical binocular. Dazzling Venus and conspicuous Mars will be easy targets and require no optical aid to see, but the third — Uranus — will require a telescope since it will otherwise be lost in the glare of Venus since they are separated by just 0.1°.

While it’s often said that there are five naked-eye planets (Mercury, Venus, Mars, Jupiter and Saturn), outer gas giant Uranus can just be seen with the unaided eye from dark, moonless locations when favourably placed, but not tonight.

The close proximity of Venus makes finding Uranus spectacularly easy since they will be in the same telescopic field of view, but the difference in brightness — nearly ten magnitudes, or 9100 times — provides a striking contrast.

$1:

This is a simulated telescopic view of Venus and Uranus at 100x magnification around 7 pm on 4th March. Under average skies, Uranus may be a challenge to glimpse just 0.1° away from the dazzle of Venus — much depends on the quality of your optics, too. This orientation of Uranus with respect to Venus assumes a Newtonian telescope with an inverted view on an alt-azimuth mount; with an equatorial mount, Uranus will lie above Venus in such a telescope. In a refractor, Schmidt-Cassegrain or Maksutov telescope with a star diagonal, Uranus will lie below Venus. AN graphic by Ade Ashford

http://astronomynow.com/2015/03/04/plan ... njunction/

If you are looking at the moon tonight, you'll also see Jupiter. It's the bright 'star', high in the sky. A pair of binoculars is all you need to see it.

[DrCaleb]

$1:

Hubble Shows Mirror, Mirror, Mirror, Mirror of an Ancient Supernova

Researchers using the Hubble Space Telescope took advantage of a naturally occurring zoom lens in space to capture an unprecedented quadruple image of an ancient supernova.

Between the supernova and the Earth-orbiting Hubble observatory lies a massive galaxy cluster whose gravity bends the path of the traveling photons. The existence of so-called “gravitational lenses” was proposed 100 years ago by physicist Albert Einstein. The first cosmic lens was discovered in 1979.

“Einstein’s theory of general relativity says that massive objects bend space and time. Light traveling close to massive objects will have their paths’ bent,” said astronomer Jennifer Lotz, with the Space Telescope Science Institute in Baltimore.

In addition to testing Einstein’s theory of relativity, this type of curved light could be used to measure how fast the universe is expanding.

Astronomer Patrick Kelly, with the University of California Berkeley, and colleagues report this week about four different routes light from an ancient supernova took to reach the Hubble telescope after being deflected around an intervening elliptical galaxy. The phenomenon is known as an Einstein cross.

http://news.discovery.com/space/astrono ... 150305.htm