Bursts of star birth can curtail future galaxy growth
Astronomers using the NASA/ESA Hubble Space Telescope have shown for the first time that bursts of star formation have a major impact far beyond the boundaries of their host galaxy. These energetic events can affect galactic gas at distances of up to twenty times greater than the visible size of the galaxy — altering how the galaxy evolves, and how matter and energy is spread throughout the Universe.
When galaxies form new stars, they sometimes do so in frantic episodes of activity known as starbursts. These events were commonplace in the early Universe, but are rarer in nearby galaxies.
During these bursts, hundreds of millions of stars are born, and their combined effect can drive a powerful wind that travels out of the galaxy. These winds were known to affect their host galaxy — but this new research now shows that they have a significantly greater effect than previously thought. An international team of astronomers observed 20 nearby galaxies, some of which were known to be undergoing a starburst. They found that the winds accompanying these star formation processes were capable of ionising gas up to 650,000 light-years from the galactic centre — around twenty times further out than the visible size of the galaxy.The starburst galaxies within the sample were seen to have large amounts of highly ionised gas in their halos — but the galaxies that were not undergoing a starburst did not. The team found that this ionisation was caused by the energetic winds created alongside newly forming stars.
This has consequences for the future of the galaxies hosting the starbursts. Galaxies grow by accreting gas from the space surrounding them, and converting this gas into stars. As these winds ionise the future fuel reservoir of gas in the galaxy’s envelope, the availability of cool gas falls — regulating any future star formation.
Image credit: ESA, NASA, L. Calçada
“Maybe we’re on Mars because of the magnificent science that can be done there - the gates of the wonder world are opening in our time. Maybe we’re on Mars because we have to be, because there’s a deep nomadic impulse built into us by the evolutionary process, we come after all, from hunter gatherers, and for 99.9% of our tenure on Earth we’ve been wanderers. And, the next place to wander to, is Mars. But whatever the reason you’re on Mars is, I’m glad you’re there. And I wish I was with you.” — Carl
The First Animal Astronauts
These pioneering space animals did not volunteer to travel into space, but their adventures captured the imagination of millions as they watched these animals make history.
- Laika, a mixed-breed dog, was the first living being in orbit. She was launched on the Soviet Union’s Sputnik 2 mission in November of 1957.
- A rhesus monkey named Sam is shown after his flight in December of 1959, which tested the launch-escape system of NASA’s Mercury spacecraft.
- Enos the chimpanzee being readied for his orbital spaceflight of November 1961.
Charted: Extraterrestrial Driving Records
NASA has just released this cute chart depicting the various distances traveled by wheeled machines on other worlds (click to enlarge).
The comparison was put out in honor of the agency’s Opportunity rover, which has been on Mars since 2004, beating NASA’s previous distance record-holder, the Apollo 17 moon buggy. During its nine years of operations, Opportunity has roved 35.760 kilometers, edging out the Apollo astronaut’s 35.744-kilometer drive.
The champion for driving on another surface still goes to the Soviet Lunokhod 2 rover, which traveled 37 kilometers across the moon in 1973. Of course, Opportunity still has the *ahem* opportunity to overtake the international record holder since it’s continuing to rove around the rim of Endeavour crater on Mars. The little robot has been exploring that area since 2011 and has uncovered some of the most unambiguous evidence for water on ancient Mars. Though NASA’s celebrated Curiosity rover has only gone less than one kilometer since landing in August, it has nuclear batteries that could last 14 years at minimum — ample time to beat all competitors.
I have long been fascinated by gamma-ray bursts (or GRBs). These are incredibly violent events: It’s like taking the Sun’s entire lifetime energy output and cramming into a single event that lasts for mere seconds! The energy emitted is so intense, so bright, we can see GRBs from a distance of billions of light years.
Gamma rays themselves are just a form of light, like the kind we see, but with huge energy; each photon is packed with millions or billions of times the energy in a single photon of visible light. Only the most energetic events in the Universe can make them, so if we detect a burst of them coming from the sky, we know something literally disastrous has happened.
We know GRBs come in many flavors. Some last literally for milliseconds, while others stretch on for minutes. We also know different events can cause them, too. Short ones seem to come from merging neutron stars, ultra dense compact objects left over after stars explode. The longer ones occur when massive stars explode, leaving their cores to collapse. In both cases, the huge blast of high-energy gamma rays signals the birth of a black hole.
But astronomers were recently surprised to find a third type of GRB, one that lasts not for minutes, but for hours. Whatever these objects are, they don’t just flash with light, they linger, blasting out far, far more gamma rays for far, far longer than was previously thought. What could do such a thing?
Several ideas were put forth, but new observations provided the linchpin: an ultra-long-duration GRB occurred on Christmas Day in 2010, and its distance was found to be a soul-crushing 7 billion light years away, about halfway across the visible Universe! This left only one possible candidate for the progenitor: a hugely massive star, one so big it dwarfs the Sun into insignificance.
Satellites orbiting Earth (2013)
Over a millenia ago Earth witnessed an explosion in the heavens, that explosion was later discovered to be a supernova. Now, new data from NASA’s Chandra X-ray observatory adds to the awesome factor of SN 1006 and supernovae like it, which provides new details about the remains of this exploded star. As noted in Chandra’s official site:
“The Chandra data provides the best map to date of the debris field including information on important elements expanding into space.”
A new image of SN 1006 from NASA’s Chandra X-ray Observatory reveals this supernova remnant in exquisite detail. By overlapping ten different pointings of Chandra’s field-of-view, astronomers have stitched together a cosmic tapestry of the debris field that was created when a white dwarf star exploded, sending its material hurtling into space. In this new Chandra image, low, medium, and higher-energy X-rays are colored red, green, and blue respectively.
The Chandra image provides new insight into the nature of SN1006, which is the remnant of a so-called Type Ia supernova . This class of supernova is caused when a white dwarf pulls too much mass from a companion star and explodes, or when two white dwarfs merge and explode. Understanding Type Ia supernovas is especially important because astronomers use observations of these explosions in distant galaxies as mileposts to mark the expansion of the Universe.
Jupiter’s moon Io, photographed by Voyager 2, 10 July 1979.
The end of this blog’s Io-thon follows on from yesterday’s post. The photos used in this gif were taken with longer exposures than yesterday’s, so there is a better contrast between Io and the background. Two volcanic eruptions are clearly visible in the top-left: I think that they are from Amirani and Maui. There’s also an eruption on the right-hand side, but as its only lit by reflected light from Jupiter, it requires a lot of brightening to see (NASA’s photojournal shows it here).
You can also see a volcano in the south, tall enough to stay in sunlight even as the surrounding areas fall into darkness.
Yesterday I mentioned the bright spot glinting near the equator. I asked Jason Perry (who used to write an Io blog) about it on Twitter and he said that it “looks like specular reflection off of glassy, cooled lava near Hi’iaka Patera.” So there you go.
I look up — many people feel small because they’re small and the Universe is big — but I feel big, because my atoms came from those stars. There’s a level of connectivity.
That’s really what you want in life, you want to feel connected, you want to feel relevant, you want to feel like a participant in the goings on of activities and events around you.
That’s precisely what we are, just by being alive…
- Dr. Neil DeGrasse Tyson [ x ]
The Swiss telescope in 1976
The Swiss 0.4-metre telescope was installed on La Silla in 1975 and run by the Geneva Observatory for photometric studies.
Image credit: ESO
Earth has the technology to deflect an asteroid, but scientists won’t be able to use those methods without ample time to implement them.
Mimas emerging from behind Saturn. Photographed by Cassini, 26 October 2007.
An amazing new photo from a telescope in Chile has captured the most detailed view yet of a green glowing blob 3,300 light-years away from Earth.
Image: This photo shows the glowing green planetary nebula IC 1295 surrounding a dim and dying star. It is located about 3300 light-years away from Earth. Credit: ESO
The new image, released today (April 10) by the European Southern Observatory, shows the planetary nebula IC 1295 like it has never been seen before. This picture, which ESO scientists dubbed “ghostly,” marks the first time the nebula has been imaged such unprecedented detail.
“It has the unusual feature of being surrounded by multiple shells that make it resemble a microorganism seen under a microscope, with many layers corresponding to the membranes of a cell,” officials from the European Southern Observatory wrote in a statement.
Stars like the sun eventually run out of hydrogen fuel and puff-up into red giants at the end of their lives — a precursor to a suicidal shedding of gas, decimating any nearby planets, eventually leaving a tiny white dwarf remnant. But a nearby star, located around 100 light-years away, has been spotted in the brief stage before the red giant phase of its death throes — and it has a dusty disk usually exclusive to young stars.