Artist's conception of Planck, a space observatory operated by the European Space Agency, and the cosmic microwave background. Credit: ESA and the Planck Collaboration - D. Ducros
There have been a lot of attempts over the years to figure out the mass of a neutrino (a type of elementary particle). A new analysis not only comes up with a number, but also combines that with a new understanding of the universe’s evolution.
The research team investigated the mass further after observing galaxy clusters with the Planck observatory, a space telescope with the European Space Agency. As the researchers examined the cosmic microwave background (the afterglow of the Big Bang), they saw a difference between their observations and other predictions.
“We observe fewer galaxy clusters than we would expect from the Planck results and there is a weaker signal from gravitational lensing of galaxies than the CMB would suggest. A possible way of resolving this discrepancy is for neutrinos to have mass. The effect of these massive neutrinos would be to suppress the growth of dense structures that lead to the formation of clusters of galaxies,” the researchers stated.
The HST WFPC2 image of gravitational lensing in the galaxy cluster Abell 2218, indicating the presence of large amount of dark matter (credit Andrew Fruchter at STScI).
Neutrinos are a tiny piece of matter (along with other particles such as quarks and electrons). The challenge is, they’re hard to observe because they don’t react very easily to matter. Originally believed to be massless, newer particle physics experiments have shown that they do indeed have mass, but how much was not known.
There are three different flavors or types of neutrinos, and previous analysis suggested the sum was somewhere above 0.06 eV (less than a billionth of a proton’s mass.) The new result suggests it is closer to 0.320 +/- 0.081 eV, but that still has to be confirmed by further study. The researchers arrived at that by using the Planck data with “gravitational lensing observations in which images of galaxies are warped by the curvature of space-time,” they stated.
“If this result is borne out by further analysis, it not only adds significantly to our understanding of the sub-atomic world studied by particle physicists, but it would also be an important extension to the standard model of cosmology which has been developed over the last decade,” the researchers stated.
Palikir Crater as seen by the Mars Reconnaissance Orbiter's High Resolution Imaging Science Experiment (HiRISE) camera. Visible are warm-season flows called "recurring slope linea" that could have been created by salty liquid water. Credit: NASA/JPL-Caltech/UA/JHU-APL
One hotspot of debate are flows called “recurring slope lineae”, which are features that appear in warmer temperatures. These would seem to imply some kind of briny water flowing. A team recently checked out 13 of these sites. While they didn’t find any water or salt evidence in the spectra, they did find more iron-bearing minerals on “RSL slopes” compared to those that aren’t. So what’s going on?
“We still don’t have a smoking gun for existence of water in RSL, although we’re not sure how this process would take place without water,” stated Lujendra Ojha, a graduate student at the Georgia Institute of Technology in Atlanta who led two reports on these features. Pictures were taken using NASA’s Mars Reconnaissance Orbiter’s High Resolution Imaging Science Experiment (HiRISE), which is led by the University of Arizona.
Palikir Crater as seen by the Mars Reconnaissance Orbiter’s High Resolution Imaging Science Experiment (HiRISE) camera. Visible are warm-season flows called “recurring slope linea” that could have been created by salty liquid water. Credit: NASA/JPL-Caltech/UA/JHU-APL
It’s possible that the grains are being sorted by size (more plainly speaking, taking the fine dust away and leaving the larger grains behind), which could happen either with water or without it. Or, water might be present but not in a way that is obvious immediately if the area got darker because of moisture, or the minerals became oxidized. Water could be “missing” from these observations because they took place in the afternoon (meaning they could miss morning dew), or because the dark flows are smaller than the sample size in the picture.
While researchers still aren’t sure, the team says they still believe it’s salty water of some sort that is flowing despite very cold temperatures on Mars.
“The flow of water, even briny water, anywhere on Mars today would be a major discovery, impacting our understanding of present climate change on Mars and possibly indicating potential habitats for life near the surface on modern Mars,” said Richard Zurek, MRO project scientist who is at NASA’s Jet Propulsion Laboratory in California.
A related paper also found that RSL sites are rare on Mars, appearing in only 13 of 200 sites surveyed with similar slopes, latitudes and other features. You can read the accepted versions of the reports as they appear in Geophysical Research Letters and Icarus.
Astrophotographers are already getting some great images of Mars, such as this sequence captured by Efrain Morales Rivera on January 9th, 2014.
Get those telescopes ready: the coming months offer Earthbound viewers some great views of the planet Mars.
Mars reaches opposition for 2014 on April 8th. This is approaching season represents the best time to observe Mars, as the Red Planet is closest to us in April and rises in the east as the Sun sets opposite to it in the west. Mars reaches 10” in apparent size this week. Mars is already beginning to show surface detail through a moderate-sized telescope as it continues to grow. In mid-February, Mars currently rises at around midnight local, and rides high to the south at local sunrise.
Mars imaged by Leo Aerts on February 3rd. Shot using a Celestron 14″ scope, DMK 21AU618 webcam with a 2.5 powermate projection and a RGB Baader filter set.
The 2014 opposition of Mars offers a mixed bag for observers. Hanging around 5-10 degrees south of the celestial equator just east of the September equinoctial point in Virgo, viewing opportunities are roughly equal for both northern and southern hemisphere observers. At opposition, Mars will shine at magnitude -1.5 and present a 15.2” disk, only slightly larger than the near minimum apparition of 2012, when it appeared 13.9” across. This is a far cry from the historic 2003 appearance, when Mars nearly maxed out at 25.1” across.
Why such a difference? Because the planet Mars has an exceptionally eccentric orbit. In fact, the eccentricity for Mars is 9.3% compared to 1.7% for the relatively sedate Earth.
A decade plus of Mars oppositions, from 2012 through 2025. Graphic created by the author.
This guarantees that all oppositions of Mars – which occur roughly 26 months/780 days apart – are not created equal. In our current epoch, Mars can pass anywhere from 0.683 to 0.373 Astronomical Units (A.U.s) from the Earth. This year’s passage sees Mars overtake us at 0.62 A.U.s or over 96 million kilometres from Earth on the night of opposition. Mars is slightly closer to us at 0.618 A.U.s six nights later on April 14th.
Why the slight difference? Well, the speedier Earth is on the inside track headed towards aphelion in July, while Mars is lagging but headed slightly inward towards perihelion just afterwards in September. This combined motion makes for a slightly closer approach just after opposition until the Earth begins to pull away.
And this also means that Mars will make its apparent retrograde loop through Virgo on the months surrounding opposition:
The motion of Mars through Virgo from March 1st through July 31st. Created by the author using Starry Night Education software.
Now for the good news. Oppositions of Mars also follow a rough 15-year cycle, meaning that they get successively closer or more distant with every two year passage. For example, the 1999 opposition of Mars had a very similar geometry to this year’s, as will to the future opposition in 2029.
And we’re currently on an improving trend: the next opposition in 2016 is much better than this year’s at 18.6” in size, and during the 2018 opposition, Mars will present a disc 24.3” across and will be nearly as favorable as the one in 2003!
It’s also worth noting that Mars sits within four degrees of the rising Moon on the evening of April 14th. The bright star Spica also sits even closer to the Full Moon on the same evening, at less than two degrees away. This particular evening is also noteworthy as it hosts the first of two lunar eclipses for 2014, both of which favor North America.
Mars, the Full Moon and Spica rising in the east on April 14th. Created using Stellarium.
Can you catch Mars near the Moon before sundown on the 14th using binoculars? The Moon will also occult Mars on July 6th for viewers across central and South America.
Though Mars is nicknamed the Red Planet, we’ve seen it appear anywhere from a pumpkin orange to a sickly yellow hue. In fact, such a jaundiced color change can be a sign that a planet-wide dust storm is under way. Such a variation can be readily seen with the naked eye. What color does Mars appear like to you tonight?
On Mars, northern hemisphere summer starts on February 15th, 2014. This means that the northern pole cap of the planet is tipped towards us at opposition during 2014. The day on Mars is only slightly longer than Earth’s at 24 hours and 37 minutes, meaning that Mars will have seemed to rotated only an extra ~8 degrees if you observe it at the same time on each successive evening.
The white pole caps of the planet are the first feature that becomes apparent to the observer at the eyepiece. In February, Mars shows a noticeable gibbous phase in February as we get a peek at the edge of the nighttime side of the planet. Mars will be nearly “full” at opposition, after which it’ll once again take on a slightly distorted football shape.
A growing (& shrinking) Mars through the 2014 opposition season. Created by the author using Starry Night Education software.
Tracking the features of the Red Planet is also possible at moderate magnification. One of the largest features apparent is the dark area known as Syrtis Major. Sky & Telescope has an excellent and easy to use application named Mars Previewer that will show you which longitude is currently facing Earth.
Sketching the regions of Mars is a fun exercise. You’ll find that drawing planetary features at the eyepiece can sharpen your observing skills and give you a more critical eye to discern subtle detail. And this season also provides an excellent reason to turn that newly constructed planetary webcam towards Mars.
Up for a challenge? Opposition is also a great time to try and observe the moons of Mars.
The moons of Mars as seen on April 8th at around 9:00 Universal Time. Created by the author using Starry Night Education software.
Phobos and Deimos are a tough catch, but are indeed within range of amateur instruments. The chief problem lies in their close proximity to dazzling Mars: +11.5 magnitude, Phobos never strays 14” from the Red Planet in 2014, and 12.4 magnitude Deimos never travels farther than 45” away. Phobos orbits Mars once 7.7 hours — faster than the planet rotates beneath it — and Deimos orbits once every 30.3 hours. The best strategy for a successful Martian moon hunt is to either place Mars just out of the field of view at high power when a moon reaches greatest elongation or block it from view using an eyepiece equipped with an occulting bar.
Extra credit for anyone who nabs pics of the pair!
And opposition is also “Visit Mars season,” as MAVEN and India’s Mars Orbiter Mission arrive later this year. In 2016, NASA’s Mars InSight mission is slated to make the trip, and the window is fast-closing for Dennis Tito’s proposed crewed fly-by mission of Mars in 2018.
And finally, to aid you in your quest for those elusive Martian moons, reader and human astronomical calculator extraordinaire Ed Kotapish was kind enough to compile a list of favorable apparitions of the moons of Mars on the weeks surrounding opposition. (see below)
Good luck, and be sure to send in those pics of Mars and more to Universe Today!
ELONGATIONS OF THE MARTIAN MOONS
DATES AND TIMES IN UT
STARTING 3/30/2014
MAR 30
PHOBOS 0300 W
PHOBOS 0645 E
DEIMOS 0900 W
PHOBOS 1040 W
PHOBOS 1425 E
PHOBOS 1815 W
PHOBOS 2205 EMAR 31
DEIMOS 0005 E
PHOBOS 0155 W
PHOBOS 0545 E
PHOBOS 0935 W
PHOBOS 1320 E
DEIMOS 1515 W
PHOBOS 1715 W
PHOBOS 2100 E
APR 01
PHOBOS 0055 W
PHOBOS 0440 E
DEIMOS 0620 E
PHOBOS 0830 W
PHOBOS 1220 E
PHOBOS 1610 W
PHOBOS 2000 E
DEIMOS 2130 W
PHOBOS 2350 W
APR 02
PHOBOS 0340 E
PHOBOS 0730 W
PHOBOS 1115 E
DEIMOS 1235 E
PHOBOS 1510 W
PHOBOS 1855 E
PHOBOS 2245 W
APR 03
PHOBOS 0235 E
DEIMOS 0345 W
PHOBOS 0625 W
PHOBOS 1015 E
PHOBOS 1405 W
PHOBOS 1755 E
DEIMOS 1855 E
PHOBOS 2145 W
APR 04
PHOBOS 0130 E
PHOBOS 0525 W
PHOBOS 0910 E
DEIMOS 1000 W
PHOBOS 1305 W
PHOBOS 1650 E
PHOBOS 2040 W
APR 05
PHOBOS 0030 E
DEIMOS 0110 E
PHOBOS 0420 W
PHOBOS 0810 E
PHOBOS 1200 W
PHOBOS 1550 E
DEIMOS 1615 W
PHOBOS 1940 W
PHOBOS 2325 E
APR 06
PHOBOS 0320 W
PHOBOS 0705 E
DEIMOS 0725 E
PHOBOS 1055 W
PHOBOS 1445 E
PHOBOS 1835 W
PHOBOS 2225 E
DEIMOS 2230 WAPR 07
PHOBOS 0215 W
PHOBOS 0605 E
PHOBOS 0955 W
PHOBOS 1340 EDEIMOS 1340 E (Mutual)
PHOBOS 1735 W
PHOBOS 2120 E
APR 08
PHOBOS 0115 W
DEIMOS 0445 W
PHOBOS 0500 E
PHOBOS 0850 W
PHOBOS 1240 E
PHOBOS 1630 W
DEIMOS 1955 E
PHOBOS 2020 E
APR 09
PHOBOS 0010 W
PHOBOS 0355 E
PHOBOS 0750 W
DEIMOS 1100 W
PHOBOS 1135 E
PHOBOS 1530 W
PHOBOS 1915 E
PHOBOS 2305 W
APR 10
DEIMOS 0210 E
PHOBOS 0255 E
PHOBOS 0645 W
PHOBOS 1035 E
PHOBOS 1425 W
DEIMOS 1715 W
PHOBOS 1815 E
PHOBOS 2205 W
APR 11
PHOBOS 0150 E
PHOBOS 0545 W
DEIMOS 0825 E
PHOBOS 0930 E
PHOBOS 1320 W
PHOBOS 1710 E
PHOBOS 2100 W
DEIMOS 2330 W
APR 12
PHOBOS 0050 E
PHOBOS 0440 W
PHOBOS 0830 E
PHOBOS 1220 W
DEIMOS 1440 E
PHOBOS 1605 E
PHOBOS 2000 W
PHOBOS 2345 EAPR 13
PHOBOS 0340 W
DEIMOS 0550 W
PHOBOS 0725 E
PHOBOS 1115 W
PHOBOS 1505 E
PHOBOS 1855 W
DEIMOS 2055 E
PHOBOS 2245 E
APR 14
PHOBOS 0235 W
PHOBOS 0620 E
PHOBOS 1015 W
DEIMOS 1205 W
PHOBOS 1400 E
PHOBOS 1755 W
PHOBOS 2140 E
APR 15
PHOBOS 0130 W
DEIMOS 0310 E
PHOBOS 0520 E
PHOBOS 0910 W
PHOBOS 1300 E
PHOBOS 1650 W
DEIMOS 1820 W
PHOBOS 2040 E
APR 16
PHOBOS 0030 W
PHOBOS 0415 E
PHOBOS 0810 W
DEIMOS 0925 E
PHOBOS 1155 E
PHOBOS 1545 W
PHOBOS 1935 E
PHOBOS 2325 W
APR 17
DEIMOS 0035 W
PHOBOS 0315 E
PHOBOS 0705 W
PHOBOS 1055 E
PHOBOS 1445 W
DEIMOS 1540 E
PHOBOS 1830 E
PHOBOS 2225 W
APR 18
PHOBOS 0210 E
PHOBOS 0605 W
DEIMOS 0650 W
PHOBOS 0950 E
PHOBOS 1340 W
PHOBOS 1730 E
PHOBOS 2120 W
DEIMOS 2200 E
Credit: Inside Science News Service and Amanda Page
As the Beatles strummed the opening notes to “All My Loving” on the Ed Sullivan Show 50 years ago yesterday, few could have imagined how wide-ranging that music would be. The broadcast gave birth to a global music phenomenon. And like all TV broadcasts of the day, the music carried out into space at the speed of light.
The Inside Science infographic above (see below for the full version) traces the history of the Beatles in relation to how far the broadcast travelled in that time. While those waves were washing out, er, across the universe, the Beatles have been taking over human space exploration in other ways. Below the jump are seven of the more memorable moments.
Rocking The Space Station With ‘Back at the ISS’
Technically speaking, this isn’t the Beatles, but it sure was inspired by them. ‘Back at the ISS’ — the remake of ‘Back in the U.S.S.R.’ by Dutch band Love & Mersey — is about a billion shades of awesome. Not only because of the lyrics, not only because of the high-energy space-themed video, but also because they sang in three languages. The song was released in March 2012 as a “rocking musical greeting” to Andre Kuipers (a European Space Agency astronaut) and the rest of the Expedition 30 crew days before the docking of the Automated Transfer Vehicle Edoardo Amaldi that month.
The Beatles have been used to wake up several shuttle crews, and also the Curiosity rover. Explained Eric Blood, Curiosity’s surface systems engineer: “She tends to be less cranky with a good wakeup song.”
Playing (And Drinking?) English Tea In Space
Here’s Paul McCartney in 2005 casually playing two tunes to the Expedition 12 crew — NASA astronaut Bill McArthur and Russian cosmonaut Valery Tokarev — during a live concert. It’s a bit hard to tell who had bigger stars in their eyes after the experience. “I told the audience ‘I think I need about 20 minutes to go have a lie down,’ McCartney stated in a NASA release from the time. “What do you do after that? We haven’t stopped talking about it since.”
Roll Over Beethoven: How The Beatles Almost Made Voyager’s ‘Golden Record’
Remember when scientists announced last year that Voyager 1 entered interstellar space? On board the spacecraft was a Golden Record intended to give aliens a glimpse into what Earth’s life is like. Included were songs from artists ranging from Bach to Blind Willie Johnson, but not the Beatles. They were almost included, though, as astronomer Carl Sagan (who chaired the selection committee) explained in his 1978 book Murmers of Earth. “We wanted to send ‘Here Comes The Sun’ by the Beatles, and all four Beatles gave their approval. But the Beatles did not own the copyright, and the legal status of the piece seemed too murky to risk,” he wrote.
Joining Mr. Mercury’s Light
There are so many earthly memorials to John Lennon after the singer’s untimely death in 1980, but late last year he got an extraterrestrial honor. Lennon was among 10 names approved for craters on the planet Mercury. “It’s unlikely that Mercury’s surface is populated with tangerine trees and marmalade skies, but the famous British musician who coined that phrase now has a physical presence on the planet closest to the Sun,” NASA said.
Sending Love To The Aliens With Jai Guru Deva Om
February 4, 2008 marked the first time NASA beamed any song into deep space, and what better choice than “Across The Universe”? The date marked the 40th anniversary of when the Beatles recorded the song, and came around the same time as the 45th anniversary of NASA’s Deep Space Network and the 50th anniversary of NASA’s first satellite, Explorer 1, among other milestones. In a statement, McCartney asked to “send my love to the aliens.”
What Beatles milestones in space have we missed? Let us know in the comments.
One of the most striking features of the climate change ‘debate’ is that it’s no longer a debate. Climate scientists around the world agree that climate change is very real — the Earth is warming up and we are the cause.
Yet while there is consensus even among the most reserved climate scientists, a portion of the public persistently disagrees. A recent Pew Research Center — an organization that provides information on demographic trends across the U.S. and the world — survey found that roughly four-in-ten Americans see climate change as a global threat. Climate scientists are racking their brains in an attempt to find out why.
Yale law professor Dan Kahan has done extensive research which reveals how our deep-rooted cultural dispositions might interfere with our perceptions of reality.
Why We Resist Climate Change
In 2010 Kahan led a study, “Cultural Cognition of Scientific Consensus,” which found that individuals tend to weigh evidence and credit experts differently based on cultural considerations. Psychological mechanisms allow individuals to selectively credit or dismiss evidence and experts, depending on whether the views presented match the dominant view of their group.
“There is an interdependence between people’s prior beliefs about risk and their exposure to and understanding of information,” Kahan told Universe Today. “People are motivated to search out information in a biased way. They look more for information that is consistent with their views than for information that is going to refute their views.”
Kahan’s study was administered online to 1,500 U.S. adults. Preliminary analyses wanted to determine if the public thought there was a scientific consensus regarding climate change and if there was a scientific consensus regarding human activity as the cause.
A majority — 55 percent — of the subjects reported their opinion that most scientists agree that global temperatures are rising, 12 percent believed most scientists do not find that global temperatures are rising, and 33 percent believed that scientists are divided on the topic. On whether or not human activity is the cause, 45 percent believed scientists agree that human activity is the cause, 15 percent believed scientists don’t think human activity is the cause, and 40 percent believed scientists are divided on the topic.
The public is generally not in a position to investigate the data for themselves or even read a scientific paper full of unfamiliar acronyms, plots and equations. Instead they turn to experts for assistance. Often times in determining who is credible, individuals will trust those who share similar world views and personal values. They tend to seek information congenial to their cultural predispositions.
For Kahan’s first experiment, the subjects read the biographical information of an expert scientist. They had to decide whether he was credible, having earned a Ph.D. from an elite university and now serving as a faculty member of another elite university. Those who listed themselves as hierarchical — believing in stratified social roles (generally conservatives) — were more likely to find the expert scientist credible, while those who listed themselves as communitarian — expecting individuals to secure their own well-being (generally liberals) — were more likely to find the expert scientist not credible.
These fictional individuals were identified as credible or not based on their biographies only. Credit: Kahan et al. 2010
However, a second experiment showed the subjects not only the resume of the expert scientist but his position as well. Half the subjects were shown evidence that the expert believed in climate change, placing us at a high risk, while the other half of the subjects were shown evidence that the expert didn’t believe in climate change, placing us at a low risk.
The position imputed by the expert scientist dramatically affected the responses of the subjects. When the expert scientist supported a high risk position, 23 percent of the hierarchs and 88 percent of the communitarians found him credible. In contrast, when the expert scientist supported a low risk position, 86 percent of the hierarchs and 47 percent of the communitarians found him credible.
Whether the expert scientist was considered credible was highly associated with whether he took the position dominant in the subject’s cultural group. The subjects “have dispositions that are connected to their values that then will affect how they make sense of information,” Kahan said.
The percentage of subjects who found the author credible depending on whether he supported a high risk (climate change is real) or low risk (climate change is not real) position. Credit: Kahan et al. 2010
At the end of the day the conclusion is simple: we’re human. And this leads us to take the path of least resistance: we choose to believe in what those around us believe.
So it’s not that people aren’t sufficiently rational. “They’re too rational,” Kahan said. “They’re too good at extracting from the information you’re giving them, which sends the message that tells them what position they should take given the kind of person they are.”
Moving Forward
Kahan’s study shows that scientific consensus alone will not sway the public. The public will remain polarized despite efforts to increase trust in scientists or simply awareness of scientific research. Instead the key is to use science communication strategies, which reduce the likelihood the public will find climate change threatening.
In a more recent study, published in Nature, Kahan analyzed two techniques of science communication that may help break the connection between cultural predispositions and the evaluation of information.
The first technique is to frame the information in a manner that doesn’t threaten people’s values. In this study, Kahan and his colleagues asked participants to once again assess the credibility of climate change. But before doing so the subjects had to read an article.
One article was a study suggesting that carbon dissipates from the atmosphere much slower than scientists had previously thought. As a result, if we stopped producing carbon today, there would still be catastrophic effects: rising sea level, drought, hurricanes, etc. Another article (shown to a different group) gave information on geo-engineering or nuclear power — potential technological advances that may help reduce the effects of climate change. A final control group read an unrelated article on traffic lights.
Logically all of these articles had nothing to do with whether climate change is valid. But psychologically these articles did determine the meaning that people attached to the evidence of climate change. In all cases the hierarchs were less likely than the communitarians to say climate change is valid. But the gap was 29 percent smaller among the group that was first exposed to geo-engineering than the group that was exposed to regulating carbon.
“The evidence of whether there is a problem doesn’t depend on what you’re going to do about it,” Kahan said. “But psychologically it can make a difference.”
People tend to resist scientific evidence that may lead to restrictions on their personal activities, or evidence that threatens them as individuals But if they are presented with information in a way that upholds their identities, they react with an open mind.
The second technique is to ensure that climate change is vouched for by a diverse set of experts. If a particular group is able to identify with that expert, then that group will be more open-minded in addressing the study. This will help reduce the initial polarization between hierarchs and communitarians.
Kahan argues that science “needs better marketing.” It needs to combine climate change with meanings that are affirming rather than threatening to people. When groups can identify with the expert, or are presented with possible solutions to climate change, the individuals in that group will stop attaching the issues to identity.
According to Kahan, in order to move forward, science communication needs to change the narrative. It needs to mitigate the connection between climate change and the individual. In order for there to be a public consensus on climate change it has to be presented in a less threatening manner.
This doesn’t mean that science communication has to avoid the nasty truth about climate change in order to finally reach a public consensus. Instead it has to spin climate change in a positive way — a way that is less threatening to the individual.
Science communication has to focus the public’s attention on what so many individuals value: efficiency, not being wasteful, innovation and moving forward. Only then will the public reach a consensus where there is now only polarization.
Hubble Space Telescope deep image of galaxy cluster Abell 2744. Credit: NASA, ESA, J. Lotz, M. Mountain, A. Koekemoer, and the HFF Team (STScI), and N. Laporte (Instituto de Astrofisica de Canarias)
Peering deep into the universe with the Hubble Space Telescope, a team of researchers have found an extremely distant galaxy. It was discovered in Abell 2744, a galaxy cluster. The galaxy (called Abell2744_Y1) was spotted at a time when it was just 650 million years after the universe-forming Big Bang (which makes it more than 13 billion years old).
This demonstrates the potential of a relatively new project, researchers said, called “Hubble Frontier Fields.” It’s part of an effort where Hubble and fellow NASA space telescopes Spitzer and the Chandra X-ray Observatory will examine six galaxy clusters that bend the light from more distant objects in the background. By doing this, researchers hope to learn more about galaxies formed in the universe’s first billion years.
“We expected to find very distant galaxies close to the cluster core, where the light amplification is maximum. However, this galaxy is very close to the edge of the Hubble image where the light is not strongly amplified,” stated Nicolas Laporte, a post-doctoral researcher at the Institute of Astrophysics of the Canary Islands (Instituto de Astrofisica de Canarias) who led the study.
“We are really lucky that we could find it in the small field of view of Hubble. In a related study led by Hakim Atek … more galaxies are analyzed but none is more distant than Abell2744_Y1.”
Artistic view of a radiating black hole. Credit: NASA
A new paper has been posted on the arxiv (a repository of research preprints) introducing the idea of a Planck star arising from a black hole. These hypothetical objects wouldn’t be a star in the traditional sense, but rather the light emitted when a black hole dies at the hands of Hawking radiation. The paper hasn’t been peer reviewed, but it presents an interesting idea and a possible observational test.
When a large star reaches the end of its life, it explodes as a supernova, which can cause its core to collapse into a black hole. In the traditional model of a black hole, the material collapses down into an infinitesimal volume known as a singularity. Of course this doesn’t take into account quantum theory.
Although we don’t have a complete theory of quantum gravity, we do know a few things. One is that black holes shouldn’t last forever. Because of quantum fluctuations near the event horizon of a black hole, a black hole will emit Hawking radiation. As a result, a black hole will gradually lose mass as it radiates. The amount of Hawking radiation it emits is inversely proportional to its size, so as the black hole gets smaller it will emit more and more Hawking radiation until it finally radiates completely away.
Because black holes don’t last forever, this has led Stephen Hawking and others to propose that black holes don’t have an event horizon, but rather an apparent horizon. This would mean the material within a black hole would not collapse into a singularity, which is where this new paper comes in.
Diagram showing how matter approaches Planck density. Credit: Carlo Rovelli and Francesca Vidotto
The authors propose that rather than collapsing into a singularity, the matter within a black hole will collapse until it is about a trillionth of a meter in size. At that point its density would be on the order of the Planck density. When the the black hole ends its life, this “Planck star” would be revealed. Because this “star” would be at the Planck density, it would radiate at a specific wavelength of gamma rays. So if they exist, a gamma ray telescope should be able to observe them.
Just to be clear, this is still pretty speculative. So far there isn’t any observational evidence that such a Planck star exists. It is, however, an interesting solution to the paradoxical side of black holes.
The Universe is vast bubble of space and time, expanding in volume. Run the clock backward and you get to a point where everything was compacted into a microscopic singularity of incomprehensible density. In a fraction of a second, it began expanding in volume, and it’s still continuing to do so today.
So how old is the Universe? How long has it been expanding for? How do we know? For a good long while, Astronomers assumed the Earth, and therefore the Universe was timeless. That it had always been here, and always would be.
In the 18th century, geologists started to gather evidence that maybe the Earth hadn’t been around forever. Perhaps it was only millions or billions of years old. Maybe the Sun too, or even… the Universe. Maybe there was a time when there was nothing? Then, suddenly, pop… Universe.
It’s the science of thermodynamics that gave us our first insight. Over vast lengths of time, everything moves towards entropy, or maximum disorder. Just like a hot coffee cools down, all temperatures want to average out. And if the Universe was infinite in age, everything should be the same temperature. There should be no stars, planets, or us.
The brilliant Belgian priest and astronomer, George Lemaitre, proposed that the Universe must be either expanding or contracting. At some point, he theorized, the Universe would have been an infinitesimal point – he called it the primeval atom. And it was Edwin Hubble, in 1929 who observed that distant galaxies are moving away from us in all directions, confirming Lemaitre’s theories. Our Universe is clearly expanding.
Which means that if you run the clock backwards, and it was smaller in the distant past. And if you go back far enough, there’s a moment in time when the Universe began. Which means it has an age. The next challenge… figuring out the Universe’s birthdate.
Time line of the Universe (Credit: NASA/WMAP Science Team)
In 1958, the astronomer Allan Sandage used the expansion rate of the Universe, otherwise known as the Hubble Constant, to calculate how long it had probably been expanding. He came up with a figure of approximately 20 billion years. A more accurate estimation for the age of the Universe came with the discovery of the Cosmic Microwave Background Radiation; the afterglow of the Big Bang that we see in every direction we look.
Approximately 380,000 years after the Big Bang, our Universe had cooled to the point that protons and electrons could come together to form hydrogen atoms. At this point, it was a balmy 3000 Kelvin. Using this and by observing the background radiation, and how far the wavelengths of light have been stretched out by the expansion, astronomers were able to calculate how long it has been expanding for.
Initial estimates put the age of the Universe between 13 and 14 billion years old. But recent missions, like NASA’s WMAP mission and the European Planck Observatory have fine tuned that estimate with incredible accuracy. We now know the Universe is 13.8242 billion years, plus or minus a few million years.
We don’t know where it came from, or what caused it to come into being, but we know exactly how our Universe is. That’s a good start.
Shepherd moon Prometheus hovers just inside the reflective F ring
Lit by eerie, reflected light from Saturn’s F ring (and a casting a faint shadow through a haze of icy “mist”) Saturn’s moon Prometheus can be seen in the raw image above, captured by Cassini’s narrow-angle camera on Feb. 5 from a distance of 667,596 miles (1,074,392 km). It’s also receiving some light reflected off Saturn, which is off frame at the top (where the outermost edge of the A ring and the Keeler gap can be seen.)
As the potato-shaped Prometheus approaches the ring it yanks fine, icy material in towards itself, temporarily stretching the bright particles into long streamers and gaps and even kicking up bright clumps in the ring. It’s a visual demonstration of gravity at work! Watch an animation of this below, made from images acquired just before and after the one above:
Streamers and clumps created by the passing Prometheus on Feb. 5, 2014. (NASA/JPL/SSI. Animation by Jason Major.)
At its longest Prometheus is about 92 miles (148 km) across, but only 42 miles (68 km) in width. It circles Saturn in a wave-shaped, scalloping orbit once every 14.7 hours.
