صور

Ashes to Ashes, Dust to Dust: The Fate of Stars Like the Sun

Posted by

Ashes to Ashes, Dust to Dust: The Fate of Stars Like the Sun
Greg Sloan of the Space Telescope Science Institute

Our Sun, though seemingly eternal, is about halfway through its roughly 10-billion-year lifespan. What will happen when the Sun dies? Not only will the answer be important to whoever inhabits Earth in a few billion years, it is important to astronomers today. Quiet stars like the Sun are many times more numerous than large stars and play a major role in how galaxies develop. Importantly, how these stars die determines when life can first form in the galaxy.

Host: Dr. Frank Summers

Recorded live on Tuesday, August 7 at the Space Telescope Science Institute in Baltimore, Maryland, U.S.A.

More information: http://hubble.stsci.edu/about_us/public_talks/

Tonight’s Sky: August 2018

Posted by

Save the date to watch the peak of the Perseid meteor shower—an always-anticipated feature of the night sky—August 12 and 13th. This month, backyard telescopes will also reveal sunlight reflecting off the clouds of Venus’s thick atmosphere and the Ring Nebula, an expanding shell of glowing gas in the constellation Lyra.

“Tonight’s Sky” is produced by HubbleSite.org, online home of the Hubble Space Telescope. This is a recurring show, and you can find more episodes—and other astronomy videos—at http://hubblesite.org/videos/science

Milky Way Center in Multiple Wavelengths [UltraHD]

Posted by

Our solar system and sun is located inside a pancake shaped galaxy. Imagine a scale model where the plane of the Milky Way is a DVD, and the central bulge is a ping pong ball glued in the center. It is this narrow plane that we see across the sky on a sufficiently dark night from Earth, from our vantage point inside it. Dust blocks much of our view. But at other wavelengths astronomers can probe the heart of our galaxy.

The center of our Milky Way Galaxy, located 26,000 light-years away, houses a black hole as massive as a million suns, surrounded by very dense nest of stars and bright clouds. The density of stars in the innermost regions of the Milky Way is up to one million times greater than in our portion of the galaxy. This region contains extreme and unusual conditions that can influence the types of stars that reside there. The density of stars and clouds creates streaming patterns. There are large massive star clusters that cannot not be found outside that region. The radiation environment is intense in the galactic center.

The near-infrared image (Hubble) shows the knots of cloud edges and emission that mark the plane of our galaxy. The mid-infrared image (Spitzer) highlights the clouds of gas and dust and star forming regions. The X-ray image (Chandra) tracks the most luminous and powerful stars in the area conspicuously revealing the galactic center region itself – including the million-solar mass black hole at the very hub of our galaxy. In addition, several other X-ray emitting locations can be seen, linked to massive star clusters.

Video: NASA, ESA, and G. Bacon (STScI)
Image Credits: NASA, ESA, CXC, SSC and STScI

The Milky Way’s Bulge: From a Hypothesized Blob to a Remarkably Detailed Picture

Posted by

The Milky Way’s Bulge: From a Hypothesized Blob to a Remarkably Detailed Picture
David Nataf of Johns Hopkins University

The central bulge of our Milky Way galaxy is host to roughly 30 percent of its stars, including a substantial fraction of both the oldest stars and the most metal-rich stars. The ages of the stars indicate that some formed via hierarchical collapse early in the universe, while most formed later on, due to dynamical processes within the disk. The differences in chemical abundances among the stars may have effects on the formation of planets and the evolution of life. Astronomers’ understanding and characterization of the Milky Way bulge creates a relatively complex picture, but it is still incomplete.

Host: Dr. Frank Summers

Recorded live on Tuesday, July 3 at the Space Telescope Science Institute in Baltimore, Maryland, U.S.A.

More information: http://hubble.stsci.edu/about_us/public_talks/

Galaxy Collision Simulation [Dome Version]

Posted by

In this scientific visualization, two spiral galaxies are set on a collision course. As one slices through the other, both are disrupted. The tidal forces of gravity produce long tails of material streaming away from the collision. The central regions relatively quickly fall together and merge. The visualization is based on research data from a supercomputer simulation, with stars shown in yellow and gas shown blue. Time passes at about 30 million years per second, lasting a total of about 1.5 billion years.

This version was rendered for a planetarium dome format (polar coordinate hemisphere projection). The camera choreography was designed for uni-directional seating, where there is a common focus point of the audience (front and center, about 60 degrees up).

The camera motion is somewhat complex, and can be discerned by watching the movement of the background galaxy field. The camera starts by dropping down to reveal the first galaxy in the front right and then the second galaxy to the front left. The camera also moves in toward the galaxies to get a closer view of the initial collision. After the initial collision, the camera continues to drop slowly, now increasing the distance to the galaxies and tilting a bit to keep the tidal tails on screen as much as possible. The camera also rotates slowly to increase the sweeping feel of the tidal tails passing above.

Visualization: Frank Summers, Space Telescope Science Institute

Simulation: Chris Mihos, Case Western Reserve University, and Lars Hernquist, Harvard University