Showing posts with label through. Show all posts
Showing posts with label through. Show all posts

Sunday, May 18, 2014

ESA Venus Express VITRIS: Ready to aerobrake through planet's atmosphere

This global view of the southern hemisphere of Venus is a mosaic of images obtained by the Visible and Infrared Thermal Imaging Spectrometer (VIRTIS) on board ESA’s Venus Express on 16 May 2006. 

The night-side hemisphere (in red at the top) is made of infrared images taken at 1.74 micrometres, showing the lower layers of the cloud deck surrounding the planet at about 45-km altitude. 

The day-side hemisphere (in blue at the bottom) is made of ultraviolet images taken at 480 nanometres. 

It shows the cloud top layer at about 65-km altitude. 

The red part of the central panel was taken at 3.8 micrometres, and shows the double vortex at the south pole, at an altitude of about 60 km, surrounded by a collar of ‘cold’ air. 

Credit: ESA /VIRTIS-VenusX IASF-INAF, Observatoire de Paris (R.Hueso, Univ. Bilbao)

Tuesday, April 29, 2014

Possible meteor shower May 23-24 as Earth passes through dust trail of 209P/LINEAR

Composite photo of Lyrid meteor shower and non-Lyrids taken with a NASA all-sky camera April 21-23, 2012. 

A new meteor shower emanating from Camelopardalids near the North Star is expected to light up the skies the morning May 24 around 2 a.m. CDT (7 UT). 

Credit: NASA /MSFC /Danielle Moser

On Friday night/early Saturday May 23-24 skywatchers across the U.S. and southern Canada may witness the birth of a brand new meteor shower.

If predictions hold true, Earth will pass through multiple tendrils of dust and pebbly bits left behind by comet 209P/LINEAR, firing up a celestial display on par with the strongest showers of the year. Or better.

Earlier predictions called for a zenithal hourly rate or ZHR of 1,000 per hour, pushing this shower into the 'storm' category.

ZHR is an idealized number based on the shower radiant located at the zenith under ideal skies.

The actual number is lower depending on how far the radiant is removed from the zenith and how much light pollution or moonlight is present.

Peter Jenniskens
Meteor expert Peter Jenniskens of NASA's SETI Institute and Finland's Esko Lyytinen first saw the possibility of a comet-spawned meteor storm and presented their results in Jenniskens' 2006 book Meteor Showers and Their Parent Comets.

Esko Lyytinen
Quanzhi Ye and Paul Wiegert (University of Western Ontario) predict a weaker shower because of a decline in the comet's dust production rate based on observations made during its last return in 2009. They estimate a rate of ~200 per hour.

On the bright side, their simulations show that the comet sheds larger particles than usual, which could mean a shower rich in fireballs. Other researchers predict rates between 200 and 40o per hour.

At the very least, the Camelopardalids – the constellation from which the meteors will appear to originate – promise to rival the Perseids and Geminids, the year's richest showers.

Approximate location of the radiant (blue) of the 209P/LINEAR shower at the peak of the brief maximum around 2 a.m. CDT May 24. 

Between 100-400 meteors may radiate from the dim constellation of Camelopardalids near the North Star. 

This map shows the sky from the central U.S. 

Created with Stellarium

Comet 209P/LINEAR, discovered in Feb. 2004 by the automated Lincoln Laboratory Near-Earth Asteroid Research (LINEAR) sky survey, orbits the sun every 5.04 years with an aphelion (most distant point from the sun) near Jupiter.

The OSIRIS-REx spacecraft with its sample-collecting arm resembles a standing heron and inspired Michael Toler Puzio’s inventive name for the asteroid that the OSIRIS-REx space mission will visit. 

Credit: NASA/Goddard Flight Center/University of Arizona.

In 2012, during a relatively close pass of that planet, Jupiter perturbed its orbit, bringing it to within 280,000 miles (450,000 km) of Earth's orbit.

That set up a remarkably close encounter with our planet on May 29 when 209P/LINEAR will cruise just 5 million miles (8 million km) from Earth to become the 9th closest comet ever observed.

Multiple debris trails shed by the comet as long ago as the 18th century will intersect our planet's path 5 days earlier, providing the material for the upcoming meteor shower/storm.

Read the full article here

Friday, February 19, 2010

Atlas V Breaking through the Sound Barrier



Perched on top of an Atlas V rocket, on February 11 the Solar Dynamics Observatory launched into space. About a minute after leaving the Earth, the rocket did two things: it passed the speed of sound, and screamed past a sundog, a rainbow-colored optical effect in the sky caused by ice crystals.

And when it did, well, it was incredible. What’s below is just about the coolest video I have ever seen. And I mean that seriously. Click the "720" button and pay close attention at the 1:50 mark. You won’t miss it, the crowd in the audio will alert you…

Wednesday, February 17, 2010

Pictures taken through the ISS Cupola Windows


Icy Aral Sea picture taken by ISS Astronaut Soichi through the new Cupola window installed on the Node 3 Tranquility module.


Picture of Sakura-jima, Kagoshima, Japan. An active volcano!

You can connect to Astronaut Soichi and other NASA astronauts via Twitter. @Astro_Soichi

Thursday, October 1, 2009

Galaxies speeding through clusters of their neighbours

heic0911b1

Galaxies speeding through clusters of their neighbors were imaged by the Hubble Space Telescope being stripped of their gas.

NGC 4522, the galaxy pictured above, is traveling at 6.2 million miles per hour, astronomers estimate. It’s about 60 million light-years away in the Virgo cluster. The bright blue areas to the right and left are star-forming regions.

Unlike our own Milky Way galaxy with its delicate spiral arms, fast-moving galaxies like NGC 4522 get deformed by the strong winds generated by their movement. The process is known as “ram pressure stripping” and it’s analogous to what would happen were you to hold a dandelion parachute ball out a car window. The lighter parts get stripped away.

Galaxy NGC 4402, pictured below, shows off the convex gas and dust disc that is characteristic of galaxies undergoing ram pressure stripping. The hot gas between galaxies in a cluster (known as the intra-cluster medium) actually sweeps the gas away, creating the odd shape in the process.

The images were taken by the Advanced Camera for Surveys instrument before it suffered a power failure in 2007. The images were recovered when astronauts restored the unit in May of this year on the last Hubble Servicing Mission. Both are deep enough to show distant background galaxies.