Universe Today

November 11, 2009December 24, 2015 by Jean Tate

Parallel Universe

The number of multiverses the human brain could distinguish. Credit: Linde and Vanchurin

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To some extent, ‘parallel universe’ is self-referential … there are parallel meanings of the very term! The two most often found in science-based websites (like Universe Today) are multi-verse, or multiverse (the universe we can see is but one of many universes), and the many-worlds interpretation of quantum physics (most often associated with Hugh Everett).

Cosmologist Max Tegmark (currently at MIT) has a neat classification scheme for pigeon-holing most parallel universe ideas that have at least some relationship to physics (as we know it today).

The most straight-forward kind of parallel universe(s) is one(s) just like the one we can see, but beyond the (cosmic) horizon … space is flat, and infinite, and the laws of physics (as we know them today) are the same, everywhere.

Similar, but different in some key ways, are parallel universes which developed out of inflation bubbles; these have the same (or very similar) physics to what applies in the universe we can see, except that the initial values (e.g. fine-structure constant) and perhaps number of dimensions may differ. The Inflationary Multiverse ideas of Standford University’s Andrei Linde are perhaps the best known example of this type. Parallel universes at this level tie in naturally to the (strong) anthropic principle.

Tegmark’s third class (he calls them Levels; this is Level 3) is the many-worlds of quantum physics. I’m sure you, dear reader, are familiar with poor old Schrödinger’s cat, whose half-alive and half-dead status is … troubling. In the many-worlds interpretation, the universe splits into two equal – and parallel – parts; in one, the radioactive material decays, and the cat dies; in the other, it does not, and the cat lives.

Level 4 contains truly weird parallel universes, ones which differ from the others by having fundamentally different laws of physics.

Operating somewhat in parallel are two other parallel universe concepts, cyclic universes (the parallelism is in time), and brane cosmology (a fallout from M-theory, in which the universe we can see is confined to just one brane, but interacts with other universes via gravity, which is not restricted to ‘our’ brane).

As you might expect, much, if not most, of this has been attacked for not being science (for example, how could you ever falsify any of these ideas?), but at least for some parallel universe ideas, observational tests may be possible. Perhaps the best known such test is the WMAP cold spot … one claim is that this is the imprint on ‘our’ universe of a parallel universe, via quantum entanglement (the most recent analyses, however, suggest that the cold spot is not qualitatively different from others, which have more prosaic explanations What! No Parallel Universe? Cosmic Cold Spot Just Data Artifact is a Universe Today story on just this).

Other Universe Today stories on parallel universes include If We Live in a Multiverse, How Many Are There?, Warp Drives Probably Impossible After All, and Book Review: Parallel Worlds.

Astronomy Cast has several episodes which include mention of parallel universes, but the best two are Multiple Big Bangs, and Entanglement.

Sources: MIT, Stanford University

November 11, 2009December 24, 2015 by Nancy Atkinson

Where In The Universe #79

It’s time once again for another Where In The Universe Challenge. Test your visual knowledge of the cosmos by naming where in the Universe this image was taken and give yourself extra points if you can name the spacecraft responsible for this picture. Post your guesses in the comments section, and check back on Thursday at this same post to find the answer. To make this challenge fun for everyone, please don’t include links or extensive explanations to the answer in your comments. Good luck!

UPDATE: The answer has now been posted below.

Also, if you have suggestions for a future WITU Challenge, email me.

Yes, this is us, the planet Earth as seen by Voyager 1 from 3.7 billion miles (6 billion kilometers) away. I’ll let Carl Sagan explain it: (from an address he gave in 1996 and the basis for his essay and book, “Pale Blue Dot.”)

“Look again at that dot. That’s here. That’s home. That’s us. On it everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives. The aggregate of our joy and suffering, thousands of confident religions, ideologies, and economic doctrines, every hunter and forager, every hero and coward, every creator and destroyer of civilization, every king and peasant, every young couple in love, every mother and father, hopeful child, inventor and explorer, every teacher of morals, every corrupt politician, every “superstar,” every “supreme leader,” every saint and sinner in the history of our species lived there – on a mote of dust suspended in a sunbeam.

The Earth is a very small stage in a vast cosmic arena. Think of the rivers of blood spilled by all those generals and emperors so that, in glory and triumph, they could become the momentary masters of a fraction of a dot. Think of the endless cruelties visited by the inhabitants of one corner of this pixel on the scarcely distinguishable inhabitants of some other corner, how frequent their misunderstandings, how eager they are to kill one another, how fervent their hatreds.

Our posturings, our imagined self-importance, the delusion that we have some privileged position in the Universe, are challenged by this point of pale light. Our planet is a lonely speck in the great enveloping cosmic dark. In our obscurity, in all this vastness, there is no hint that help will come from elsewhere to save us from ourselves.

The Earth is the only world known so far to harbor life. There is nowhere else, at least in the near future, to which our species could migrate. Visit, yes. Settle, not yet. Like it or not, for the moment the Earth is where we make our stand.

It has been said that astronomy is a humbling and character-building experience. There is perhaps no better demonstration of the folly of human conceits than this distant image of our tiny world. To me, it underscores our responsibility to deal more kindly with one another, and to preserve and cherish the pale blue dot, the only home we’ve ever known.”

November 11, 2009December 24, 2015 by Nancy Atkinson

Shedding Light on the Sun’s “Lithium Mystery”

Artist’s impression of a baby star still surrounded by a protoplanetary disc in which planets are forming. Credit: ESO

For decades, astronomers have known our Sun contains a low amount of lithium, while other solar-like stars actually have more. But they didn’t know why. By looking at stars similar to the Sun to study this anomaly, scientists have now discovered of a trend: the majority of stars hosting planets possess less than 1% of the amount of lithium shown by most of the other stars. “The explanation of this 60 year-long puzzle is for us rather simple,” said Garik Israelian, lead author on a paper appearing in this week’s edition of Nature. “The Sun lacks lithium because it has planets.”

This finding sheds light not only on the lack of lithium in our star, but also provides astronomers with a very efficient way of finding stars with planetary systems.

Isrealian and his team took a census of 500 stars, 70 of which are known to host planets, and in particular looked at Sun-like stars, almost a quarter of the whole sample. Using ESO’s HARPS spectrograph, a team of astronomers has found that Sun-like stars that host planets have destroyed their lithium much more efficiently than “planet-free” stars.

“For almost 10 years we have tried to find out what distinguishes stars with planetary systems from their barren cousins,” Israelian said. “We now have found that the amount of lithium in Sun-like stars depends on whether or not they have planets.”

These stars have been “very efficient at destroying the lithium they inherited at birth,” said team member Nuno Santos. “Using our unique, large sample, we can also prove that the reason for this lithium reduction is not related to any other property of the star, such as its age.”

Unlike most other elements lighter than iron, the light nuclei of lithium, beryllium and boron are not produced in significant amounts in stars. Instead, it is thought that lithium, composed of just three protons and four neutrons, was mainly produced just after the Big Bang, 13.7 billion years ago. Most stars will thus have the same amount of lithium, unless this element has been destroyed inside the star.

This result also provides the astronomers with a new, cost-effective way to search for planetary systems: by checking the amount of lithium present in a star astronomers can decide which stars are worthy of further significant observing efforts.

Now that a link between the presence of planets and curiously low levels of lithium has been established, the physical mechanism behind it has to be investigated. “There are several ways in which a planet can disturb the internal motions of matter in its host star, thereby rearrange the distribution of the various chemical elements and possibly cause the destruction of lithium,” said co-author Michael Mayor. ” It is now up to the theoreticians to figure out which one is the most likely to happen.”

Read the team’s paper.

Source: ESO

November 11, 2009April 26, 2016 by Jean Tate

Parabolic Mirror

Herschel in 3-D. Credit: Nathanial Burton-Bradford.

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Sometimes, in astronomy, the name of a thing describes it well; a parabolic mirror is, indeed, a mirror which has the shape of a parabola (an example of a name that does not describe itself well? How about Mare Nectaris, “Sea of Nectar”!). Actually, it’s a circular paraboloid, the 3D shape you get by rotating a parabola (which is 2D) around its axis.

The main part of the standard astronomical reflecting telescope – the primary mirror – is a parabolic mirror. So too is the dish of most radio telescopes, from the Lovell telescope at Jodrell Bank, to the telescopes in the Very Large Array; note that the dish in the Arecibo Observatory is not a parabolic mirror (it’s a spherical one). Focusing x-ray telescopes, such as Chandra and XMM-Newton, also use nested parabolic mirrors … followed by nested hyperbolic mirrors.

Why a parabolic shape? Because mirrors of this shape reflect the light (UV, IR, microwaves, radio) from distant objects onto a point, the focus of the parabola. This was known in ancient Greece, but the first telescope to incorporate a parabolic mirror wasn’t made until 1673 (by Robert Hooke, based on a design by James Gregory; the reflecting telescope Newton built used a spherical mirror). Parabolic mirrors do not suffer from spherical aberration (spherical mirrors cannot focus all incoming, on-axis, light onto a point), nor chromatic aberration (single lens refracting telescopes focus light of different colors at different points), so are the best kind of primary mirror for a simple telescope (however, off-axis sources will suffer from coma).

The Metropolitan State College of Denver has a cool animation of how a parabolic mirror focuses a plane wave train onto a point (the focus).

Universe Today has many articles on the use of parabolic mirrors in telescopes; for example Kid’s Telescope, Cassegrain Telescope, Where Did the Modern Telescope Come From?, Nano-Engineered Liquid Mirror Telescopes, A Pristine View of the Universe … from the Moon, Largest Mirror in Space Under Development, and 8.4 Metre Mirror Installed on Huge Binoculars.

Telescopes, the Next Level is an excellent Astronomy Cast episode, containing material on parabolic mirrors.

November 11, 2009December 24, 2015 by Nancy Atkinson

Up, Up and Away! Helium Balloon Telescope Explores the Sun

SUNRISE enables tiny magnetic fields on the surface of the Sun to be measured at a level of detail never before achieved. Credit: Image: MPS/IMAX consortium

Exploring the Sun via helium balloon almost sounds like an adventure for an animated movie, but the SUNRISE balloon-borne telescope has captured data and images that show the complex interplay on the solar surface to a level of detail never before achieved. As in the video above, SUNRISE shows our local star to be a bubbling, boiling mass where packages of gas rise and sink, lending the sun its grainy surface structure. Dark spots appear and disappear, clouds of matter dart up – and behind the whole thing are the magnetic fields, the engines of it all.

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“Thanks to its excellent optical quality, the SUFI instrument was able to depict the very small magnetic structures with high intensity contrast, while the IMaX instrument simultaneously recorded the magnetic field and the flow velocity of the hot gas in these structures and their environment,” said Dr. Achim Gandorfer, project scientist for SUNRISE at the Max Planck Institute for Solar System Research.

Previously, the observed physical processes could only be simulated with complex computer models.
“Thanks to SUNRISE, these models can now be placed on a solid experimental basis,” said Manfred Schüssler, co-founder of the mission.

SUNRISE is the largest solar telescope ever to have left Earth. It was launched from the ESRANGE Space Centre in Kiruna, northern Sweden, on June 8, 2009. The total equipment weighed in at more than six tons on launch. Carried by a gigantic helium balloon with a capacity of a million cubic meters and a diameter of around 130 meters, SUNRISE reached a cruising altitude of 37 kilometers above the Earth’s surface.

In the stratosphere, observational conditions are similar to those in outer space. The images are no longer affected by air turbulence, and the camera can also zoom in on the Sun in ultraviolet light, which would otherwise be absorbed by the ozone layer. After making its observations, SUNRISE separated from the balloon, and parachuted safely down to Earth on June 14th, landing on Somerset Island, a large island in Canada’s Nunavut Territory.

Grainy sun: the images show the so-called granulation in four different wavelengths in near ultraviolet light. The image section depicts 1/20,000 of the entire surface. The smallest recognisable structures have an angular resolution equal to that of looking at a coin from a distance of 100 kilometres. The light structures are the foundational elements of the magnetic fields. Credit: Image: MPI for Solar System Research

The work of analyzing the total of 1.8 terabytes of observation data recorded by the telescope during its five-day flight has only just begun. Yet the first findings already give a promising indication that the mission will bring our understanding of the Sun and its activity a great leap forward. What is particularly interesting is the connection between the strength of the magnetic field and the brightness of tiny magnetic structures. Since the magnetic field varies in an eleven-year cycle of activity, the increased presence of these foundational elements brings a rise in overall solar brightness – resulting in greater heat input to the Earth.

The variations in solar radiation are particularly pronounced in ultraviolet light. This light does not reach the surface of the Earth; the ozone layer absorbs and is warmed by it. During its flight through the stratosphere, SUNRISE carried out the first ever study of the bright magnetic structures on the solar surface in this important spectral range with a wavelength of between 200 and 400 nanometers (millionths of a millimeter).

SUNRISE is a collaborative project between the Max Planck Institute for Solar System Research in Katlenburg-Lindau, with partners in Germany, Spain and the USA.

Source: PhysOrg

November 11, 2009December 24, 2015 by Jean Tate

Horsehead Nebula

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The Horsehead nebula is a dark nebula that looks like a horse’s head! It is part of the Orion Molecular Cloud complex, and has the more correct, if boring, name Barnard 33 (being object number 33 in a catalog of dark nebulae, by Barnard).

It is about 1500 light-years away, and is itself dark because of the dust of which it’s made (it’s also made up of gas, in fact it’s mostly gas, but the gas is essentially transparent). What makes it so obvious is the diffuse glow from behind it; the glow is red – due to the Balmer Hα line, a prominent atomic transition in hydrogen – and is powered by the UV light from the nearby star, Sigma Orionis (which is actually a five-star system), which ionizes the hydrogen gas in this part of the Orion Complex.

The first record of its shape is from 1888, by Williamina Fleming, who noticed it on a photographic plate taken at the Harvard College Observatory (Fleming made significant contributions to astronomy, including cataloguing many of the stars in the famous Henry Draper Catalogue). The Horsehead nebula is a favorite of amateur astronomers, especially astrophotographers (it’s quite difficult to spot visually).

The Horsehead nebula is similar to the Pillars of Creation (in M16), though perhaps not as dense; one day it too will be eroded by the intense UV from the young stars in its vicinity, and from new-born stars formed within it (the bright area at the top left is light from just such a star).

In 2001, the Hubble Space Telescope Institute asked the public to vote for an astronomical target for the Hubble Space Telescope to observe, a sort of Universe Idol contest … the Horsehead nebula was the clear winner! Hands up all of you who have, or have had, the Hubble’s image of the Horsehead as your wallpaper, or perhaps the VLT one …

Universe Today has, among its stories, some good background on the Horsehead; for example Dark Knight Ahead – B33 by Gordon Haynes, Astrophoto: The Horsehead Nebula by Filippo Ciferri, and What’s Up This Week – Jan 3 – Jan 9, 2005.

The Astronomy Cast episode Nebulae explains the role of dark nebulae, such as the Horsehead, in starbirth; well worth a listen.

Sources: NASA APOD, Wikipedia

November 11, 2009December 24, 2015 by Nancy Atkinson

Stunning Cassini Image to Knock Your Socks Off

What a way to start the day! This image is one of the first things I saw online this morning. The moon Rhea hangs like a pendant against Saturn and its rings. Amazingly, this is a raw image straight from Cassini; it has not been calibrated or enhanced in any way. This is art in its purest form and evidence of the phenomenal and enchanting beauty of the Saturn system, as well as confirmation of what an amazing spacecraft Cassini is.

This image was taken on November 08, 2009 and received on Earth November 09, 2009. The camera was pointing toward Rhea at approximately 1,874,061 kilometers away.

Here’s the link to a higher resolution version.

Source page.

Hat tip to @mars_stu on Twitter

November 10, 2009December 24, 2015 by Nicholos Wethington

Vatican Holds Conference on Extraterrestrial Life

Though it may seem an unlikely location to happen upon a conference on astrobiology, the Vatican recently held a “study week” of over 30 astronomers, biologists, geologists and religious leaders to discuss the question of the existence of extraterrestrials. This follows the statement made last year by the Pope’s chief astronomer, Father Gabriel Funes, that the existence of extraterrestrials does not preclude a belief in God, and that it’s a question to be explored by the Catholic Church. The event, put on by the Pontifical Academy of Sciences, took place at the Casina Pio IV on the Vatican grounds from November 6-11.

The conference was meant to focus on the scientific perspective on the subject of the existence of extraterrestrial life, and pulled in perspectives from atheist scientists and Catholic leaders alike. It was split into eight different segments, starting with a topics about life here on Earth such as the origins of life, the Earth’s habitability through time, and the environment and genomes. Then the detection of life elsewhere, search strategies for extrasolar planets, the formation and properties of extrasolar planets was discussed, culminating in the last segment, intelligence elsewhere and ‘shadow life’ – life with a biochemistry completely different than that found on Earth.

Speakers at the event included notable physicist Paul Davies and Jill C. Tarter, the Director of the Center for SETI Research. Numerous astrobiologists and astronomers researching extrasolar planets also were in attendance to give lectures. The whole series of speech abstracts and a list of participants is available in a brochure on the Vatican site, here.

The event was held to mark the International Year of Astronomy, and the participants hope to collect the lectures into a book. Father Gabriel Funes, the chief astronomer of the Vatican, said in an interview to the Vatican paper, Osservatore Romano last year:

“Just like there is an abundance of creatures on earth, there could also be other beings, even intelligent ones, that were created by God. That doesn’t contradict our faith, because we cannot put boundaries to God’s creative freedom. As saint Francis would say, when we consider the earthly creatures to be our “brothers and sisters”, why couldn’t we also talk about a “extraterrestrial brother”? He would still be part of creation.”

Even with the discovery of over 400 exoplanets, the question of extraterrestrial life still remains to be answered in our own Solar System. It is a pertinent question for the religious and non-religious alike. Though it wasn’t answered at this most recent conference, the existence of life outside what we know here on Earth has an equal impact on the findings of science as it does the meaning of religion. This event certainly brought the two under the same roof for what were surely some interesting and fruitful conversations.

Source: Physorg, Pontifical Academy of Sciences

November 10, 2009December 24, 2015 by Nancy Atkinson

Good News for Science News

Here’s some refreshing news! In an era when mainstream media is cutting back on their science departments and science reporting, the Discovery Channel has just made an investment to step-up their science news with the re-launch of their new and improved news website, Discovery News. In the middle of it all is our very own Ian O’Neill, who is also the producer for Discovery News Space. The “new” part of Discovery News is that Ian’s work on the space side is now integrated into a higher profile, redesigned news site. Ian and I had a chance to talk today about this good news for science news.

“Discovery News was always the Discovery Channel website’s news source. It has been around for about 11 years,” Ian told me, “and people started coming to the Discovery Channel website specifically to read Discovery News, so it was always like a little news agency bubbling around in the background.”

About 18 months ago Discovery News put together three different “hubs” to focus on space, Earth and technology. Those three headings are now given top billing on the new site, integrating news and blogs together.

Ian and I talked about how Universe Today wears both hats as both a news site and a blog, and Discovery News is doing that as well, but in a bigger way with over 20 correspondents, producers and editors.

“We know we have to have both strong traditional reported items as well as opinion based pieces, and we now have a nice relationship between the two,” Ian said. “Blogging has become a major news source for a lot of people, as a lot of the blogs are now written by science professionals. There doesn’t seem to be that big distinction or chasm anymore between a reported item and what is opinion, and often the two fade in between.”

All the Discovery News contributors have professional backgrounds in their fields, and it’s great to see a “big” company investing in science-based journalism.

“They have created the opportunity for Discovery News to relaunch, and given us the resources to perhaps be a one-of-a kind science news site,” Ian said.

Check out Discovery News.

November 10, 2009December 24, 2015 by Mark Mortimer

the Bluffer’s Guide to the Cosmos

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The English language continually evolves. Just see Ambrose Bierce’s definition of dictionary. New concepts call for new words that often evolve from a new dictum. Astronomy has made its fair share of contributions to this cause. But, Daniel Hudon’s book “The Bluffer’s Guide to: The Cosmos” belies such augmentations. Within, the language is as common and everyday as what you used around the gas pump or barber shop. Yet, the science and information is as exact and appropriate as needed to communicate an idea.

The idea of a bluffer’s guide is, presumably, to allow a reader without formal training to wax eruditely about a particular topic. The Cosmos is, of course, pretty big. In fact it’s about as big as things get from our perspective. Yet, the book’s undaunted brashness allows a reader to become familiar with the heady concepts of cosmology. Its material is current, as noted by the reference to eight planets in our solar system. It’s humorous, as noted by fun sounding words like Zubenelgenubi. And it’s short and sweet, as noted by its small format and brief 86 pages. However, the few pages allow for the book to entertain the reader rather than drown them in details.

The focus on providing for the reader’s entertainment remains a fixture throughout the book. Thus, true to the title’s promise, a reader might be able to bluff their way through a conversation about the Cosmos after having read it. But, this book would better serve those readers who simply want to relate an unknown, difficult sounding subject to their own everyday perceptions. For instance, if the Earth is the size of an apple, then Uranus is the size of a honey dew melon. Or, consider the Big Bang to be like a cosmic burp happening 13.7 billion years ago. With this technique, the book should keep the naïve reader interested and also keep them reading to the end.

With cosmologists continually adding to society’s knowledge base, the everyday person could easily get overwhelmed with new phrases like ‘mysterious energy’. Yet, Daniel Hudon’s book “The Bluffer’s Guide to: The Cosmos” can come to the rescue. It succinctly delivers these ideas into simple, common verbiage and should keep the reader smiling at the same time.