Astronomy Picture of the Day 5-02-03

NASA ^ | 5-02-03 | Robert Nemiroff and Jerry Bonnell

[petuniasevan]

Astronomy Picture of the Day

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2003 May 2

Five to Mars
Image Credit: USGS, Viking Project, NASA

Explanation: Come December 2003 - January 2004, an armada of five new invaders from Earth should arrive on the shores of the Red Planet -- the Japanese ( ISAS) Nozomi orbiter, the European Space Agency's Mars Express orbiter carrying the Beagle 2 lander, and NASA's own two Mars Exploration Rovers. While Nozomi began its interplanetary voyage in 1998, the other spacecraft are scheduled for launch windows beginning this June. Clearly, earthdwellers remain intensely curious about Mars and the tantalizing possibility of past or present martian life, with these robotic missions focussing on investigating the planet's atmosphere and the search for water. This mosaic of over 100 Viking 1 orbiter images of Mars was recorded in 1980 and is projected to show the perspective seen from an approaching spacecraft at a distance of 2,000 kilometers. Exceptional views of Mars will be possible from earthbound telescopes in August and September.

[petuniasevan]

Vacation Announcement

I will be on vacation from June 2nd through June 9th.
If anyone would like to volunteer to post APOD during that time, please FReepmail me.
Otherwise the APOD will not be posted as I will be visiting relatives in California.

On the night of August 26-27, Mars will be close to Earth. The centers of the two planets will then be only 55.758 million kilometers (34.646 million miles) apart. At that time Mars will shine at magnitude -2.9 in the constellation Aquarius. You can't miss it. The only bright star in that area is Fomalhaut at magnitude 1.15.

Right now Mars is in Capricorn at magnitude 0 (about as bright as the star Vega). Look to the southeast in the wee hours of the morning for a reddish non-twinkling "star".

Notice that the planets don't twinkle? That's because they are not "point sources" as stars are; rather they are visually "disks". For instance, Mars right now has an angular size of 10 seconds of arc. For comparison, the Moon subtends an angle of 30 minutes of arc. The planets' apparent size cancels out Earth's atmospheric effect on point source images. For an overview of the "twinkling" phenomenon, see the 25 July 2000 APOD

[petuniasevan]

[foolish-one]

Good morning and thank you.

[MikeD]

For those of you who don't want to do the math, that means that the Moon is 180 times wider in the sky than Mars.

MD

[xJones]

Warmer temperatures and a higher surface pressure once made it possible for liquid water to exist on the surface of Mars. When the water existed and where it went are just two of the questions being studied today.

Okay, why did Mars cool off and lose surface pressure? Was that all that caused it to lose it's surface water?

[firewalk]

Thanks for the ping

[sistergoldenhair]

Thanks for the ping.

[RightWhale]

Dry, cold, dark and no air. Make no mistake, coloning Mars will be no picnic. Colonizing Mars also makes no business sense. So it will be done anyway, but for science or religious reasons.