Tag Archives: Space

Discovered: Monster Black Holes, The Most Massive Ones Ever!

There are monsters out there that are larger than anything we can imagine or know! This feeling was once again reaffirmed yesterday, when scientists published results that told them of two new supermassive blackholes that turn out to be bigger than any known so far. These two weigh in at an estimated 9.7 Billion Solar masses!

An artist's impression of the transit of a blackhole across a cosmic structure.

Supermassive blackholes are known to reside in the centers of galaxies. They are presumed to grow in size by gobbling up all matter and gases that come their way. The one at the center of our own Milky Way Galaxy is estimated at a million solar masses! If you think that is big, then be prepared to be blown away.

The Giants

The largest known black hole was the Messier 87 black hole. This weighed in at a gigantic 6.3 billion solar masses. A new blackhole found in NGC 3842 in the Leo cluster is a gigantic 9.7 billion solar mass monster. This is located 320 million light years away from us. Another one has been found in NGC 4889, in the Coma cluster. This one is 335 million light years away and is similar in mass. The event horizon or the boundary beyond which nothing, not even light, can escape the gravitational force of the blackhole is bigger than the radius of the orbit of Pluto! Compare this to the Milky way blackhole, whose event horizon, by comparison, is a small one at just about one-fifth the size of the orbit of Mercury.

The Centaurus-A quasar. The photo is a merged false-color photo. It contains data from the Chandra X-ray Telescope and ground based radio telescope. The short blue emissions are X-ray emissions (caught by Chandra) and the longer orange-yellowish plumes are radio-emissions. The central galaxy is captured in optical by Hubble Space Telescope. (Courtesy: NASA/GSFC/Chandra/Hubble)

These blackholes are found by looking at the emission of the accretion disks. Matter falling in becomes so hot that it emits light in many wavelengths, including X-Ray and radio. Scientists know objects which are just about the size of a typical spiral galaxy, or even smaller, but emit radiation, which is unusually high. Such structures are called quasars’, shortened from Quasi-Stellar Objects. They are believed to be powered’ by a central blackhole engine!

The research is going to be published in Nature on 8th December.

Cosmic Spectacle: Leonid Meteor Shower To Light Up Sky Tonight

The Leonids are upon us and that means that you should cancel all your plans and just stare towards the heavens tonight. On the night of 17th November (i.e between 17th and 18th), the Leonids are going to peak in intensity and we intend to give you every piece of information you need to know about them.

Leonids are seen when the Earth moves into the trail of the comet Temple-Tuttle. They are called Leonids, since their radiant (i.e. the point in the sky from where they appear to radiate’ out) lies in the constellation of Leo. This is generally the procedure followed for naming meteor showers.

The radiant for the Leonids (Image Courtesy: ESA)

The peak this year is right on schedule and will be on 17th November. However, don’t despair if you miss it tonight. The meteor peak doesn’t fall off too sharply and you will be able to catch some streaks the day after as well, but obviously the rate will reduce.

The Leonids are one of the most prolific meteor showers known. They are also very capricious in their counts per hour. Leonids have been known to exceed 1000 streaks an hour and that becomes a scene you cannot possibly afford to miss. One such shower happened in the year 1966 and again as recently as 1999.

Details you need to know

Peak of the shower

Now for some bad news. The peak of the shower will happen at about 10 PM EST, when the radiant will be either near the horizon or below it for most places around the globe experiencing nighttime. In the US, the radiant will poke above the horizon at about 1 AM, but light pollution from the horizon can severely restrict the number of meteors you see, as many are very faint.

Avoid light pollution

We suggest that you try and go to a place which has as little light pollution as possible. Go out of the city, if possible. We recommend that you like comfortably on your back and don’t hurry things. The meteors are fickle-minded objects and there may be no sign of them for several minutes, may be even an hour. However, they will come in bunches, as the Leonids are reputed to do. Then they will relent again and not appear for quite some time. This effect will be more pronounced, if your view is blurred by smog as most of the streaks will be quite faint.

The Leonids (Courtesy: Mr. Kwown O Chul and www.astrokorea.com)
Photographing the shower

For enthusiastic photographers, here’s a quick tip. Try exposures of 5 to 10 minutes and, thus, you’ll need a tripod. Try to get as far away from the moon as possible and you should have no problems doing that here. If you’re lucky, you’ll get brilliant streaks, roughly perpendicular to the trails made by stars in the sky (photo above).

Remember that the time to watch out for is at about 12:30 AM to 1:00 AM. Happy skywatching.

Discovered: Giant Lake Underneath Surface Of Jupiter’s Moon; Could Harbor Life

If there be life outside Earth, but within the Solar System, the greatest possibility lies on either Mars or Europa, Jupiter’s frozen moon. Europa has a thick crust of solid ice, underneath which lies a huge body of water, possibly uninterrupted. What has got astronomers really interested is the fact that just 1.8 miles below the icy surface, there may be a body of water as big as all the Great Lakes combined. This is above the liquid ocean, which sits even deeper from the surface. The possibility of life in this pocketof water is tantalizing.

An artist's impression of what the lake might look like. (Illustration courtesy: Britney Schmidt and team from Texas University)

Europa – a strange world

Europa was extensively studied by the spacecraft Galileo and found that it is a strange world. The heat from the Sun could never sustain the liquid ocean underneath, but the tidal forces due to Jupiter’s giant gravitational field provides enough energy for the ice to melt underneath and form the giant ocean. This ocean is thought to lie 100 km (or 62 miles) below the surface.

The frozen surface of Europa, as seen by Galileo (Photo courtesy: Wikimedia)

Peering down

The study was done by Britney Schmidt and her team from the University of Texas, and their paper appeared in Nature today, i.e. on the 17th of November. The discovery provides an impetus for the search for life as it might be located much closer to the surface than previously thought.

This will also fuel the search for other subterranean lakes, like the one already found. Future missions to Europa could well include melting through the ice crust and taking samples from the great lake. Studies indicate that the water may be salty, and we already know how much life salt water can sustain.

The next giant leap for mankind might well be digging just 3 kilometers on an icy world far far away and inspecting the samples obtained. Maybe, just maybe, we’ll find something living.

Did The Early Solar System Have A Fifth Giant Planet That Got Ejected?

The early evolution of the Solar System clearly presents a gap in our understanding. There have been a huge number of simulations done about how the evolution might have gone, and a recent study, investigating into the dynamic instabilities of the early orbits, has reached a stunning conclusion. The startling finale is this: There was a fifth giant planet, about as big as Jupiter, that was simply ejected from the Solar System, so as to lend stability to the entire planetary system.

A missing fifth member of the group?

A Cosmic Billiard Ball Game

The study, led by Dr. David Nesvorny, looks into the instabilities when the Solar System was as young as 600 million years (about a tenth of its current age). As expected the scattering process would be dominated by the giant planets, primarily Jupiter, simply because of its high mass. It would have either gobbled up small objects coming in from the outer Kuiper belt or severely deflected them from their orbits. The problem is that this situation would be reflected in the inner Solar System too. If the orbit of Jupiter stabilized slowly, it would transfer enough momentum to deflect the orbits of Mars, Earth and Venus. They could’ve even collided into one another.

The protagonist
Jumpin’ Jupiter

The solution to this colliding billiard ball problem is to make Jupiter jump’ from one orbit to another, in what is called a Jumping Jupiter’ theory. This sudden change of Jupiter’s orbit would prevent it from transferring the large amount of momentum to the inner planets, leaving them as they are found now. However, Dr. Nesvorny found a new anomaly. Every simulation that he did with a jumping Jupiter showed Uranus or Neptune being pushed out of the Solar System. Since we see Uranus and Neptune today, this couldn’t have been the scenario.

A Fifth Giant

But, you can just add a fifth giant planet, which would play role of a leaving planet. Simulations show that this solves every problem. So the inner planets were left untouched, Jupiter jumped, Uranus and Neptune stayed within the Solar System, but a fifth giant planet had to leave the scene. This is what Dr. Nesvorny has to say:

The possibility that the solar system had more than four  giant planets  initially, and ejected some, appears to be conceivable in view of the recent discovery of a large number of free-floating planets in interstellar space, indicating the planet ejection process could be a common occurrence

Time and time again, that line from Shakespeare comes to memory There are more things in heaven and earth that are dreamt of in your philosophy.

NASA Snaps Up A Photo Of The Large Asteroid As It Passes Earth

NASA has just released a new image of the Asteroid YU55 as it continues its passage close to the Earth. The image was captured by the Deep Space Network situated in Goldstone, California. The image was taken yesterday.

The asteroid will be just a bit closer to the Earth than the moon is. Its closest approach will be about 0.85 times the distance from Earth to Moon. It will have no effect on the Earth gravitationally, including the tides. There is no truth to the various rumours and fears going around.

We covered the flyby here:  http://techie-buzz.com/science/rock-close-to-earth.html
Asteroid 2005 YU55. The image from NASA's Deep Space Network (Courtesy: NASA/JPL-Caltech)

This is the photo that was snapped up by NASA’s Deep Space Network yesterday at 11:45 PM PST. At that time the asteroid was 3.6 lunar distances away or about 1.38 million kilometers, says NASA. This is the closest any rock has got to the Earth in a very long time, the last time being in 1976. It is expected to return in 2028.

There will be more photos of the rock as it approaches closer to the Earth.

Discovered: The Youngest And Brightest Fast-Spinning Pulsar Ever Known; Contradicts Known Theory

A new batch of unusual stellar remnants (neutron stars) has been discovered and one of these challenges the currently held view of astronomy about pulsars. NASA’s Fermi Gamma Ray Telescope has discovered nine pulsars at one go, taking its discovery count past 100. Eight are simply the garden variety pulsar, but dimmer than the ones discovered so far, while one is an interesting millisecond pulsar a superfast spinning pulsar. The fact that this is the brightest and youngest millisecond pulsar ever discovered adds to the excitement.

The discovered pulsars. The millisecond one is green. (Courtesy: NASA/Fermi/Lat Collaboration)

What is a Pulsar?

“Normal” Pulsars

A pulsar is a neutron star, which emits radiation from its polar regions. A neutron star is a very compact object, resulting from the collapse of a very massive star (whose core mass is about 1.4 to 2.5 solar masses). These are extremely dense objects made up of only neutrons. Imagine shrinking the entire sun to a the radius of a few blocks in a city (say 8-10 km) and you’ll get the picture of how extreme these objects really are.

How a pulsar radiates

When these dense objects convert a part of their rotational energy into radiation, they become pulsars. The pulsation happens through a small angle opening at the two poles of the spherical object. When one of these point towards Earth, we see a pulse. Since the rotation axis and the radiation axis (which is the magnetic axis) are not aligned perfectly with each other, the pulsar acts like a lighthouse. We thus don’t get a continuous pulse of radiation, but periodic flashes. Pulsars are extremely periodic in the radiation and, thus, they make perfect timekeepers (often being more accurate than atomic clocks).

The pulsar at the Crab Nebula. The Crab Pulsar is the most famous pulsar known, attached to the 1054 supernova event. Note the jets of radiation given out! The radiation is in X-Ray Band.(Courtesy: NASA/Chandra X-Ray Telescope)

Millisecond Pulsars

When a neutron star accretes matter (generally from a companion star), it also gains a lot of angular momentum, making it spin faster. Thus, if the neutron star accretes matter, they tend to spin up. The period of rotation might reduce considerably over millions of years. Neutron stars have variable rates of rotation. The typical ones go from as slow as 5 revolutions per minute to as high as 4000 revolutions per minute.

How a millisecond pulsar forms by accreting matter from a companion star

Sometimes, the spin up of a pulsar can be so high that it can rotate more than 42,000 times a minute (or 700 times a second!!) These have a pulse period of about 1.4 milliseconds (1.4 thousandths of a second!) and are called millisecond pulsars for obvious reasons. It should be quite clear that the pulsar spin up takes a long time over several hundreds of millions of years.

What’s wrong with this new discovery?

Here’s where the problem lies! The newest millisecond pulsar that Fermi has discovered is just 25 million years old, a baby in cosmic terms. If our picture of the pulsar formation is correct, we cannot have such a young pulsar. Further, the pulsar is the brightest one ever observed. Named PSRJ1823-3021A, as per catalogue, the pulsar rotates 183.8 times a second and is 27,000 light years away from Earth. It has incredible luminosity in the gamma ray spectrum! At this moment, no one knows what to do with this one.

Along with this wonderful find, Fermi has also discovered eight other dim pulsars in the vicinity. The study was presented at the Max Planck Institute yesterday i.e. on the 3rd of November ’11.

Do Laws Of Physics Vary Across The Universe?

The warm smugness that a physicist often feels when he/she says that a phenomenon or a law is universal’ may be an illusion. If a team of researchers from Swinburne University of Technology is to be believed, then their data shows that the laws of physics might actually vary throughout the Universe. They have measured the value of the fine-structure constant, a fundamental dimensionless parameter occurring frequently in Quantum Electrodynamics, and have found that this varies throughout the Universe.

What is the Fine-Structure Constant?

The fine-structure constant, commonly called alpha’, is exactly 1/137 in its value. The constant manifests itself in the expansion parameter as one tries to expand in the theory of Quantum Electrodynamics, the physics explaining electrons, light and their interaction. The constancy of the value of alpha is crucial in establishing the universal strength of the electromagnetic force. It would mean that the strength of coupling (or interactions) between the photons (particles of light) and electrons varies throughout the Universe.

The circles represent Keck points, Triangles are both Keck and VLT. The size represents the confidence in the data points. Notice that most of the points to the middle - local to us - are black, indicating no deviation from the 1/137 value. The points farther off are not so. (Courtesy: Swinburne University of Techology, John Webb et al.)

The Research Team

A team of researchers comprising Professor John Webb, Professor Victor Flambaum and colleagues, all from University of South Wales (UNSW), Swinburne University of Technology and the University of Cambridge, had already got a hint of the supposed deviation from the accepted value of alpha as early as a decade ago. While they had used the Keck telescope in Hawaii to obtain all their data then, they’ve used the Very Large Telescope (VLT) in Chile this time. They’ve more than double their number of data points and it seems to support what they had initially thought. The confidence level has grown to a respectable 3 sigma. Professor Webb shares his excitement:

In one direction – from our location in the Universe – alpha gets gradually weaker, yet in the opposite direction it gets gradually stronger.

What Are The Consequences?

It is always the habit of scientists to back up initial observations with enough observations to fully confirm the fact. It is, thus, too early to comment what implication this will have on our understanding of the cosmos, As far as we know, the Universe is spatially homogenous (same from all points in space) and isotropic (looks the same in all directions there is no preferred direction) on a large scale (bigger than the length scale of galaxies). This is one of the basic principles of Einstein’s General Theory of Relativity  Cosmology (i.e. application of Einstein’s General Relativity – the modern theory of gravity- on the scale of the Universe). If alpha varies from point to point, then the homogeneity of space is destroyed. We can still have a weaker’ version of the homogeneity condition and General Relativity will still be true, but, having worked so well, we would like the homogeneity principle to be rigidly true. Only further observations, backed up by theory, can tell us more.

A pre-print of the arXiv paper by Webb et al is available here:  http://arxiv.org/abs/1008.3907v1
Astrophysicist Sean Carroll says that the value of alpha is probably constant. Here’s an article from him written a year ago:  http://blogs.discovermagazine.com/cosmicvariance/2010/10/18/the-fine-structure-constant-is-probably-constant/

 

Darker Matter: Observation Reveals Anomalous Dark Matter Distributions, Spells Trouble for Cosmologists

The mystery deepens. Scientists have found distribution of dark matter in dwarf galaxies, which is completely anomalous to the current theory of cold dark matter distribution in the Universe. The AMS observation from aboard the ISS has shown that dark matter is spread uniformly throughout the dwarf galaxy, whereas one would expect it to clump around the centre and then thin around towards the edges. This pattern, based on the prediction of the cold dark matter model, is seen in bigger galaxies like our own. Dwarf galaxies provide an exception and no one knows why.

A web of dark matter throughout the Universe?

What really is Dark Matter?

Dark matter refers to the attractive positive density matter that supposedly makes up as much as 23%-26% of the Universe, as compared to the 4% of visible matter (all stars, planets, galaxies everything that we know about!). The rest is dark energy and it is the energy of the vacuum, tending to tear to Universe apart making it accelerate its expansion. Dark matter was proposed by Fritz Zwicky and was initially invoked to explain the high speed of the outer spirals of a galaxy. They were spiraling too fast to be held by gravity of the visible matter. An invisible matter, interacting only through gravity had to be present. Gradually, it was recognized that dark matter could explain other things as well, like the observed cosmic microwave background radiation, unexplained gravitational lensing etc. Matter is believed to reside in the space-time trough created by lumps of dark matter.

It is to explain the motion of such galaxies that dark matter was hypothesized in the first place

The most successful version of dark matter has been the cold dark matter’ model, which says that the dark matter particles, whatever they may be, are moving very slowly with respect to light.

The Study and an Anomaly

The study involved observing the Fornax and Sculptor galaxies, which orbit the Milky Way. These are dwarf galaxies and are thought to be primarily made up of dark matter. What was expected was that the center would be rich in dark matter and then the distribution would thin out towards the edges. What was seen instead, was a uniform distribution, confounding scientists to no end. Matt Walker, the leader for this study conducted by the Harvard-Smithsonian Center for Astrophysics, says

Unless or until theorists can modify that prediction, cold dark matter is inconsistent with our observational data.

Dark matter distributions can be inferred from the motion of stars. The presence of matter curves space and matter particles follow curves on this curved space, called geodesics. The geodesics would be significantly modified by the presence of dark matter. This gives an estimate to the dark matter present. The team investigated the motion of about 2000 stars and found this anomaly.

Matt Walker says

After completing this study, we know less about dark matter than we did before

Well, nature has never been kind, has it?

Cosmic Spectacle: Watch the Brilliant Orionid Meteor Shower on Saturday, Thanks To Halley’s Comet

It’s just the debris left behind by the famous Halley comet, but is enough to light the night sky up. The Orionid meteor shower is one of the most spectacular meteor showers that occur during the year.  The shower will peak on the morning of 22nd  October, but the broad maximum means that  the shower lasts from the 20th  of October to the 24th  of October. This is widely considered to be a toned down version of the famous Perseid meteor shower.

The Radiant of the Orionids lie near Betelgeuse (red giant star) of the Orion constellation

The shower is so named since it appears to  originate from near the Orion constellation. The radiant (the point from where the shower is seen to originate) lies near the red giant star Betelgeuse in Orion (pic above).

When and What to Watch for

This time’s show should be a spectacle, given that the moon will be at its crescent stage and near the horizon at the peak of the shower. The best time to watch for the shower will be around 1:00 AM, while the moon peaks at about 2:00 AM EST.

The Orionid consists of tiny particles of debris from the parent comet of the size of sand grains. This is the trail of rubble that the Halley comet leaves behind as it makes an orbit around the Sun. The shower happens when the Earth moves through this trail. The dust falls’ through the atmosphere igniting due to the friction with the Earth’s atmosphere and causes streaks, which last for some time. These are popularly misnamed Shooting Stars’.

Prolific and long lasting

The Orionid shower is expected to produce about 20 meteors per hour on average, with the maximum likely hitting even 40 per hour, making this one of the most prolific meteor showers. However, due to the smallness of the burning pieces of debris, the shower will be drowned out by any light pollution close to your point of observation.

The signature of the Orionids is the long-lasting trails and the high speed of the particles.

You need not worry if you fail to catch the shower on the morning of 22nd October. You’ll have a chance on the 23rd and 24th as well, but the frequency will be going down steadily. Technically, the shower continues till the first week of November, but you’ll be able to see only a few stragglers’ streaking across the sky.

Happy skywatching.

‘Doomsday’ Comet Remnants To Pass By Earth On Sunday; No Armageddon Forecast

This is one conspiracy theory that can boast of being out of this world literally. The comet Elenin, dubbed the Doomsday Comet’, is due to pass Earth on Sunday, 23rd October, 2011. The comet has been closely watched by skywatchers, both out of interest and out of fear of the conspiracy theories. Some claim that Elenin is really the planet Nibiru that is destined to bring doom on Earth.

The Elenin Comet - as seen in early September. The comet has disintegrated since then.

About Elenin

Elenin started to break up late August and continued to do so till early September, due to the increased solar activity. The closest approach distance of Elenin will be approximately 22 million miles or 36 million kilometers. Elenin will be a big disappointment for both conspiracy theorists and other sane people it won’t be apocalyptic and it’ll hardly be a light show either. The comet is broken up into fragments and these pieces will not be very visible as they stream across space.

The conspiracy theory is Elenin’s only claim to fame it is a disappointing little rock orbiting the Sun with a massively eccentric orbit (i.e. one that strays away from being a circle by a long margin) and a very long period (i.e. it takes a very long time to orbit the Sun). Elenin’s return, if it survives this current journey, is projected to happen after 12,000 years.

The orbit of Elenin

Apocalypse – or not quite

There have been and will be many Armageddon theories. Rest assured that the uneventful passing of this comet will not quell the frequency of these theories. You can also be sure of the fact that this is unadulterated rubbish.

After Harold Camping and his great Doomsday prediction that spectacularly went bust, we have Nibiru (or Elenin, whichever you prefer). Everyone enjoys an apocalyptic fairy tale once in a while, right?