Medescape

Skepticism, Medicine and Science News

Water Droplets And Black Holes

Researchers at the University of Nottingham have published a paper where they use water droplets to simulate the dynamics of black holes. By using magnetic fields and electrodes they managed to spin levitating water droplets, and this produced some interresting results. As the droplet was spun at different velocities, the shape changed to form, among others, triangles,  squares and pentagons. This was due to the surface tension of the water droplet, and the scientists say this is very much like what happens at the event horizon of a black hole. The droplet experiment could hence be used to model such systems, a valuable tool in learning more about the dynamics of black holes. 

There is a video of the dropet spinning here

You spin me right round, baby. 

December 15, 2008 Posted by | Physics | , , , , , , , , , , , , , , | 1 Comment

Watch The Moon Tonight

Tonight, on Friday December 12th, the full moon will be bigger than it usually is. This is because its orbit will take it nearly as close to earth as is possible. The earth-moon distance is, on average, about 384,400 km, but tonight is is much closer, at about 356,567 km. Not since 1993 has the full moon been this close to earth, and it will take another 8 years before it happens again. Compared to the other full moons in 2008, this one will be 14% bigger and 30% brighter than any of them. So, get out and take a look. 

December 12, 2008 Posted by | Astronomy | , , , , , , , | Leave a comment

Science Quickies 3

A new study in mice shows that increased calcium sensitivity in the heart can lead to an irregular heartbeat. 

Scientists have identified 13 new tumor-suppressing genes in liver cancer. 

Scientists have calculated what they believe is the fastest 100-meter sprint time humanly possible. This was done using a mathematical model, and the time was found to be 9.48 seconds. 

A meteor streaking across parts of Canada last week was caught on video:

November 28, 2008 Posted by | General Science | , , , , , , , , , , , , , , , , | Leave a comment

Hubble Captures Two Ginormous Stars

A new picture from the Hubble Space Telescope shows two massive stars, WR 25 and Tr16-244, located in the open cluster Trumpler 16. This cluster lies within the Carina Nebula, approximately 7500 light years from earth. The nebula is home to many massive stars, including Eta Carinae, a supermassive luminous blue variable star with a luminosity four million times that of our sun, and a mass of 100-150 solar masses. WR 25 and Tr16-244 are not as big as Eta Carinae, but they are still pretty massive. 

WR 25 is located near the centre of the picture (the most blue of the big stars). It is binary star, and the largest of the two stars is a Wolf-Rayet star with a mass of about 50 solar masses. Wolf-Rayet stars are stars with a mass of >20 solar masses, and they loose their mass extremely rapidly due to a strong solar wind, typically about nine orders of magnitude more rapidly than our sun. The smaller star in the binary system is thought to have a mass of about half that of the other. 

Tr16-244 is located just to the left and up from WR 25, and is the third brightest star in the picture. The second brightest is a low-mass star much closer to earth (and thus it appears more luminous). This is a triple star, two of which are so close to each other that it took a while to determine they were in fact two separate stars. The third uses hundreds of thousands of years to orbit the first two. 

These new observations were made as part of a project led by Jesús Maíz Apellániz from the Instituto de Astrofísica de Andalucía in Spain, and consist of astronomers from the US, Argentina, Spain and Chile.

November 27, 2008 Posted by | Astronomy | , , , , , , , , , , , , , , , , , , , , , , , , | Leave a comment

Lunar Probe

As mentioned in a previous post, the Indian lunar satellite Chandrayaan-1 was launched on the 22nd of October and is now on its way to orbit the moon. One of the aspects i find most interesting about this satellite is that it carries a so-called moon impact probe. It is essentially what it sounds like, a mini-satellite (it’s only 375 mm x 375 mm x 470 mm and 35kg) that will separate from Chandrayaan-1 on Friday and then quickly de-orbit and bury itself in the lunar surface. The descent itself will only take about 25 minutes, but the probe will gather a lot of interesting data on its way down. It has a lot of different instrumentation on board, like a mass spectrometer, an altimeter etc, and the purpose of these are to analyse dust in the lunar atmosphere, and to gather data that will help test equipment that will later, hopefully, provide a soft landing for an eventual manned mission. All this is of course important and all, but what I find really exiting is the on-board CCD camera the probe carries. It will basically film the whole descent, and I really look forward to viewing that tape. Can’t wait! 

Read more about the mission and the probe in this NewScientist article.

Oh, and another cool thing is that the probe, when impacting the moon, will kick up a huge amount of dust that Chandrayaan will gather and analyse while orbiting. Yet another advantage of the low mass of the moon I guess…

 

A picture of Chandrayaan-1 from ISRO

November 12, 2008 Posted by | Astronomy | , , , , , , , , , , , , , , , , , , , , , | 1 Comment

Voyage Into Space

I stumbled upon this news item in Phil Plait’s blog, and it is extremely cool. The European Southern Observatory, or ESO, just released the deepest ultraviolet image of the Universe yet. It was taken by the Very Large Telescope (yes, that is it’s name, and it’s really a set of four telescopes working together, namely the Antu telescope, the Kueyen telescope, the Melipal telescope, and the Yepun telescope), and contains more than 27 million pixels.

    

This is a compressed version of the image, so for full resolution go here. When I first saw this picture i thought all the bright dots were stars, but no, they are in fact galaxies. Some of them are as far as 10 billion light years away, which means they are really, really young. I recommend you take a look at Phil Plait’s post about this picture. Being an astronomer he knows what he’s talking about, something I really don’t most of the time.

November 8, 2008 Posted by | Astronomy | , , , , , , , , , , , , , , , , , , , , , , , , , , | Leave a comment

Chandra X and the Crab Nebula

In 1999 NASA launched the Chandra X-Ray Observatory, which is part of NASA’s Great Observatories together with HubbleSpitzer, and Compton. Chandra X recently took a beautiful picture of the Crab Nebula

According to NASA, this is the first picture clearly showing the faint boundary of the nebula‘s X-ray emitting pulsar wind nebula. The white dot in the center is the neutron star (or pulsar) powering the nebula. Pulsars are essentially highly magnetized neutron stars that emit concentrated beams of electromagnetic radiation, which can only be observed when directed directly at earth. A pulsar will thus appear to pulsate (hence the name) when observed, and the regularity of this pulsing effect has been shown to be extremely precise, even to the level of an atomic clock. Anyhow, the rapid rotation of the pulsar in question combined with the intense electromagnetic field generated creates jets of matter and antimatter shooting out from the poles of the pulsar, and a strong wind flowing out in the equatorial direction. The inner ring surrounding the pulsar is possibly a shock wave serving as a boundary between the nebula and the matter/antimatter jets, and electrons and positrons flow outward from it, producing an extended X-ray glow. The shape of the nebula is related to the strong magnetic field, and the dark spots on the right and left is thought to be the result of a toroidal (doughnut) shaped magnetic field from a progenitor star.

November 7, 2008 Posted by | Astronomy | , , , , , , , , , , , , , , , , , , , , , , , , , , , , , | Leave a comment

Chandrayaan-1

A little over a week ago, India launched its first lunar satellite, Chandrayaan-1. The objective of the mission is, among other things, to carry out high resolution mapping of topographic features in 3D, determine distribution of various minerals and elemental chemical species and to search for surface/sub-surface water-ice at the lunar poles. Well, to test the on-board camera, Chandrayaan-1 (which translates to “moon craft”) took some really good pictures of the earth on October 29th. 

Click here for full resolution, here for another picture and here to read more about the camera test.

November 2, 2008 Posted by | Astronomy | , , , , , , , , , , , , , , , , , | Leave a comment