Venus Transit

This year has been a pretty good one so far for Earth based observations, with the Super Moon and great views of the outer planets. But it's about to get even better! Depending on where you are, you'll be able to see this year's Venus transit on either June 5th or 6th. Here's some info about it.

What is a transit?
A transit occurs when a planet moves across the face of a star. In our solar system, there are only 2 planets that we can observe transiting from Earth: Mercury and Venus. But transits do occur in all planetary systems. The Kepler telescope uses the dip in light caused by a transit to find extrasolar planets.

Image courtesy of http://www.nasa.gov/vision/universe/watchtheskies/venus_transit.html

Why is it important?
There are a few reasons this Venusian transit is important:

1. This is a pretty rare opportunity. Venusian transits occur in pairs, 8 years apart. The first transit of this pair occurred in 2004. But the time between each pair of transits is really long; the last pair occurred in the late 19th century. So this is the last viewable transit for a few generations. Read more about this at the rare alignment page.
2. We don't get a lot of chances to look at Venus from Earth. It's pretty close to the sun, and so most of our telescopes either get overwhelmed by the sun or can't pick out Venus. As it's transiting, we can see some details in silhouette. 

Where can I view the Venus transit (in Atlanta)?
In North America, the transit will be visible in the evening of June 5th. That does not mean visible as in "look straight at the sun." That's never a good idea. However, there will be several observatories with solar filters on their telescopes.

• Check out a local observatory
• The Georgia Tech Observatory: Observatory opens at 6:00 PM
• Bradley Observatory at Agnes Scott College
• The Fernbank Observatory: Observatory opens at 6 PM. Planetarium will be open from 5:30-9:30 to watch west coast streaming.

Head to a meet up of local amateur astronomers

• Meet up at Grant Park: starting at 5:30 PM
• The Atlanta Astronomy Club: event at Stone Mountain, 4-8 PM, RSVP requested

Watch online

• Live Webcast from Mauna Kea Observatory

The map below shows where and when the transit will be visible- North America catches it during sunset on June 5th.

Image Courtesy of http://eclipse.gsfc.nasa.gov/OH/tran/TOV2012-Fig01.pdf

If you can't make it to an observatory, or don't live near Atlanta, there are several safe methods for observing the transit on your own. Transit of Venus has lots of information about eye safety. We hope you get a chance to see this historic transit!

Solar Eclipse this Sunday!

If you live in the western US (or Japan or China) you are in for a treat this Sunday (May 20th): there is going to be a solar eclipse! This eclipse is actually what is known as an annular eclipse due to the fact that the outer edge of the Sun will remain visible throughout the eclipse. Due to the geometry of the eclipse, some locations will observe a partial eclipse, while others will be lucky enough to see the complete annular eclipse. Sadly, those of us on the east coast will not be able to see the eclipse at all as sunset occurs before the eclipse starts. The following clip explains a lot more details about this Sunday's event:

This should make for a truly stunning sight! Do remember that even with the Moon blocking most of the Sun's disk, the remaining light it still very intense and you should *never* look directly at the Sun without proper solar viewing glasses/telescope filters. If you find yourself without proper viewing devices you can always watch a projection of the Sun during the eclipse. A few small holes in a piece of cardboard will do the trick to watch 'many eclipses' projected on the ground, as will watching the light and shadows cast through tree branches!

The following website has viewing information for all states where the eclipse will be visible before the Sun sets: http://shadowandsubstance.com/ 

Now go outside and enjoy the show this Sunday! 

Photo Credit: Dennis Mammana (1992)
Astronomy Picture of the Day: http://apod.nasa.gov/apod/ap090125.html

   

Supermoon! *Photo Update*

Source: http://photojournal.jpl.nasa.gov/catalog/PIA14011

As if you needed an excuse to look up at the night sky, this Saturday (May 5) the full moon will seem especially big and bright. It will be most striking when it’s near the horizon.


The moon is an elliptical orbit around the Earth, meaning that its distance from the Earth can vary from a minimum of 357,000 km to a maximum of 407,000 km (the average perigee and apogee are 363,300 km and 405,500 km, respectively, and the variation over the course of the year is due to the Sun's gravitational influence as the Earth and Moon move along their orbit throughout the year).


The coincidence of a full moon and the perigee (closest distance) is what dictates a Supermoon, which is what will occur on Saturday. Not only is this when the moon is at perigee, it is on the closest edge of the range of orbital perigees locations. The effect will be most noticeable when the Moon is rising/setting as objects on the horizon lend scale to the night sky.


It should be beautiful if the clouds permit :)

For more information on this Saturday’s supermoon:
http://www.accuweather.com/en/outdoor-articles/astronomy/supermoon-alert-biggest-full-m/64627 


Update: While I'm not really a photographer, my friend Brian is! Check out his great image of the Supermoon last week:

Image Source: Brian Persten :)

Giant Sunspot!

Hello again Space Enthusiasts! Just a week after the Supermoon we are witnessing another fantastic space phenomena... a giant sunspot:

Image Source: Solar Dynamics Observatory HMI Intesitygram

http://sdo.gsfc.nasa.gov/data/

For scale, this magnetically active region is larger than the Earth! On May 10th this active region released an intense M-Class solar flare. There did not appear to be any large Coronal Mass Ejection (CME) associated with this flare, however only a day later a CME did occur that is now en route to the Earth. This bundle of energetic plasma is due to arrive at Earth's magnetosphere on May 14th, and may result in enhanced geomagnetic activity.

So you may be wondering just how frequently sunspots occur, and whether this large sunspot is unique. The answer is that the Sun is a highly dynamic object, and goes through a cycle of magnetic activity that lasts approximately 11 years and is associated with the magnetic field of the Sun reversing direction. During this cycle the Sun goes from a pretty quiescent disk to one with sunspots increasing in frequency, size, and intensity. We've been telescopically observing and cataloguing sunspots since the early 1600s, and have found a beautifully repeating pattern:

Image Source: http://www.globalwarmingart.com/wiki/File:Sunspot_Numbers_png   

We are currently ramping up to solar maximum (in 2012-2013), and therefore should see an increase in the number of sunspots and the amount of solar activity like flares, and CMEs. When the packet of energetic plasma and magnetic field that make up a CME reaches the Earth it can have a wide range of effects from generating beautifully intense aurora to damaging space borne assets to disrupting GPS and communication systems. In only the most extreme cases can the resulting geomagnetic storm (which is the general term used to describe a perturbation to the Earth's magnetosphere during a CME encounter) cause damage to electric power grids and oil pipelines, and cause redirection of cross-polar flights.

To get a realtime look at the Sun, check out the websites of the Solar Dynamics Observatory (SDO), STEREO, and the SOlar and Heliospheric Observatory (SOHO). At these sites you can view the Sun in the visible light emission (like the image above), and also see what the Sun looks like in the UltraViolet or UV part of the spectrum (in false color of course since we can't see at those wavelengths). You can also get Space Weather updates, alerts, and other great news at www.SpaceWeather.com!

The Sun in the EUV (9.4 nm) and FUV (170 nm).

Image Source: http://sdo.gsfc.nasa.gov/data/

One last riddle to leave you with: When is a sunspot not a sunspot?

Answer: 

When it's a Venus Transit!!! Coming on June 5th! 

A post on this exciting event is coming soon!

Fly me to a moon... or two... or three!

The European Space Agency (ESA) has chosen its next major mission: it's headed to Jupiter to check out three of the planet's largest moons. The JUICE mission, which stands for JUpiter ICy moon Explorer, is expected to launch in 2022 and arrive at the Jupiter system in 2030.

Source: http://www.esa.int/esaCP/SEM9I4QWJ1H_index_0.html

The ESA's selection of the JUICE mission is an exciting decision that affects planetary scientists around the world. It will provide a path for exploration of the outer solar system that will extend well beyond the current Cassini, Juno and New Horizons missions, which will all conclude within the next six years. In selecting this mission, the ESA sends a message to the scientific community that exploration of the outer solar system is an important priority.

Once JUICE arrives in the Jovian system in 2030, it will perform several flyby encounters of Callisto and Europa, and finally transfer to a suite of orbits about Ganymede. This mission is the first orbiter of an icy moon and provides the opportunity to study the potential for habitability of worlds around gas giant planets.

Source: http://photojournal.jpl.nasa.gov/catalog/PIA09352

Ganymede is definitely my favorite, as I spent most of my graduate career studying this exciting moon. It is the largest moon in the solar system.  It has a liquid water ocean beneath its icy surface. It also has aurora and is the only moon we know of that has its own magnetic field. This mission specifically seeks to characterize the extent of the subsurface ocean and its relationship to the interior structure of this fascinating moon. It will also examine the composition, distribution and evolution of surface features, and, through in situ measurements, will aid in our understanding of Ganymede's the near-space environment.

Ganymede is not the only object to be studied by this mission, the spacecraft will also spend time studying Jupiter as an archetype for a gas giant (of which we now have hundreds of exoplanet examples!). It will study Jupiter's atmosphere and magnetosphere and the coupled interactions of Jupiter and its family of icy moons. The mission also plans to execute several flyby encounters of Europa and Callisto, which will allow us to take a closer look at these beautifully diverse examples of icy worlds. Callisto is one of the oldest surfaces and represents a history of the early Jovian system. Its interior structure is a mystery, and we're excited to get better images and measurements to learn more about how this body formed and what it can tell us about the earliest 'recorded' period in the solar system. Europa has a subsurface ocean that is likely in direct contact with silicates and has demonstrated recent activity. The induced currents and magnetic fields generated in its ocean give us direct clues as to its depth and composition (compositions, along with features/structures on the surface, can tell us how active it is and where materials are sourced from).

All in all it is a very exciting time to be a planetary scientist, and I look forward to seeing this mission develop over the next decade in preparation for launch!

Source: http://photojournal.jpl.nasa.gov/catalog/PIA04532

Story reposted from my GT release: http://amplifier.gatech.edu/articles/2012/05/next-stop-jupiter