Tag: Earth

Three Almost Earth-Size Planets Found Orbiting Nearby Star

W. M. Keck Observatory press release…

A team of scientists recently discovered a system of three planets, each just larger than Earth, orbiting a nearby star called EPIC 201367065. The three planets are 1.5-2 times the size of Earth. The outermost planet orbits on the edge of the so-called “habitable zone,” where the temperature may be just right for liquid water, believed necessary to support life, on the planet’s surface. The paper, “A Nearby M Star with Three Transiting Super-Earths Discovered by K2,” was submitted to the Astrophysical Journal today and is available here.

Exoplanet Shadows
This whimsical cartoon shows the three newly discovered extrasolar planets (right) casting shadows on their host star that can been seen as eclipses, or transits, at Earth (left). Credit: K. Teramura, UH IFA
“The compositions of these newfound planets are unknown, but, there is a very real possibility the outer planet is rocky like Earth,” said Erik Petigura, a University of California, Berkeley graduate student who spent a year visiting the UH Institute for Astronomy. “If so, this planet could have the right temperature to support liquid water oceans.”

The planets were confirmed by the NASA Infrared Telescope Facility (IRTF) and the W. M. Keck Observatory in Hawaii as well as telescopes in California and Chile.

“Keck’s contribution to this discovery was vital,” said Andrew Howard, a University of Hawaii astronomer on the team. “The adaptive optics image from NIRC2 showed the star hosting these three planets is a single star, not a binary. It showed that the planets are real and not an artifact of some masquerading multi-star system.”

Due to the competitive state of planet finding, and the fact that time on the twin Keck telescopes are scheduled months in advance, the team asked UC Berkeley Astronomer, Imke de Pater to gather some data during her scheduled run.

Continue reading “Three Almost Earth-Size Planets Found Orbiting Nearby Star”

Earth at Perihelion

Today the Earth is closest to the Sun, a point called perihelion. We will be about 147,099,000km (91,403,000miles) from the Sun. Compare this to the 152,096,000km (94,508,000miles) we will be at aphelion on July 6th, a difference of about 4,996,000km (3,104,000miles) occurs throughout one orbit.

It may seem odd that we are actually at the closest for the middle of northern winter, you just have to remember that proximity to the Sun is not the cause of the seasons. The seasons are caused by the axial tilt of the Earth, creating short and long days throughout the year, with a resulting change in the angle and intensity of the sunlight.

2015 Solstices and Equinoxes
  UT HST
Perihelion Jan 4 08:59UT Jan 3 22:59HST
Vernal Equinox Mar 20 22:45UT Mar 20 12:45HST
Summer Solstice Jun 21 16:38UT Jun 21 06:38HST
Apehelion Jul 6 12:59UT Jul 6 02:59HST
Autumnal Equinox Sep 23 08:20UT Sep 22 22:20HST
Winter Solstice Dec 22 04:48UT Dec 21 18:48HST
 
Source: NASA Sky Calendar

 

Winter Solstice

Winter solstice occurs today at 13:03HST. Today the Sun will occupy the most southerly position in the sky of the year. The term solstice comes from the Latin terms Sol (the Sun) and sistere (to stand still). On this day the Sun seems to stand still as it stops moving southwards each day and begins move to the north. This is the first day of winter as marked by many cultures in the northern hemisphere. Alternately, this is the first day of summer for those folks in the southern hemisphere.

2014 Solstices and Equinoxes
  UT HST
Perihelion Jan 4 05:59UT Jan 3 19:59HST
Vernal Equinox Mar 20 16:57UT Mar 20 06:57HST
Summer Solstice Jun 21 10:52UT Jun 21 00:52HST
Apehelion Jul 3 22:59UT Jul 3 12:59HST
Autumnal Equinox Sep 23 02:30UT Sep 22 16:30HST
Winter Solstice Dec 21 23:03UT Dec 21 13:03HST
 
Source: NASA Sky Calendar

 

Apehelion

Today the Earth is furthest from the Sun, a point called apehelion. We will be about 152,096,000km (94,508,000miles) from the Sun. Compare this to the 147,099,000km (91,403,000miles) we were be at perihelion on January 3rd, a difference of about 4,996,000km (3,104,000miles) occurring throughout one orbit.

It may seem odd that we are actually at the furthest for the middle of northern summer, you just have to remember that proximity to the Sun is not the cause of the seasons. The seasons are caused by the axial tilt of the Earth, creating short and long days throughout the year, with a resulting change in the angle and intensity of the sunlight.

2014 Solstices and Equinoxes
  UT HST
Perihelion Jan 4 05:59UT Jan 3 19:59HST
Vernal Equinox Mar 20 16:57UT Mar 20 06:57HST
Summer Solstice Jun 21 10:52UT Jun 21 00:52HST
Apehelion Jul 3 22:59UT Jul 3 12:59HST
Autumnal Equinox Sep 23 02:30UT Sep 22 16:30HST
Winter Solstice Dec 21 23:03UT Dec 21 13:03HST
 
Source: NASA Sky Calendar

 

Perihelion

Today the Earth is closest to the Sun, a point called perihelion. We will be about 147,099,000km (91,403,000miles) from the Sun. Compare this to the 152,096,000km (94,508,000miles) we will be at aphelion on July 3rd, a difference of about 4,996,000km (3,104,000miles) occurs throughout one orbit.

It may seem odd that we are actually at the closest for the middle of northern winter, you just have to remember that proximity to the Sun is not the cause of the seasons. The seasons are caused by the axial tilt of the Earth, creating short and long days throughout the year, with a resulting change in the angle and intensity of the sunlight.

2014 Solstices and Equinoxes
  UT HST
Perihelion Jan 4 05:59UT Jan 3 19:59HST
Vernal Equinox Mar 20 16:57UT Mar 20 06:57HST
Summer Solstice Jun 21 10:52UT Jun 21 00:52HST
Apehelion Jul 3 22:59UT Jul 3 12:59HST
Autumnal Equinox Sep 23 02:30UT Sep 22 16:30HST
Winter Solstice Dec 21 23:03UT Dec 21 13:03HST
 
Source: NASA Sky Calendar

 

Comet C/2012 S1 ISON Closest to Earth

Hubble C/2012 S1 ISON
NASA’s Hubble Space Telescope provides a close-up look of Comet ISON (C/2012 S1). Credit:NASA, ESA, J.-Y. Li
Today comet C/2012 S1 ISON will pass closest to Earth. No worries here, close is relative in space and in this case means a comfortable 0.43 AU (64,200,000 km or 39,900,000 miles) from Earth. The comet should be easily visible well up in the dawn sky as an unaided eye object in northern Hercules.

Update: Yes, this post was written and scheduled well before the comet disintegrated at perihelion. If there is anything left it is closest to the Earth today. Many amateurs, large scopes, even Hubble have attempted to recover the remains. No one has reported finding anything.

Winter Solstice

Winter solstice occurs today at 07:11HST. Today the Sun will occupy the most southerly position in the sky of the year. The term solstice comes from the Latin terms Sol (the Sun) and sistere (to stand still). On this day the Sun seems to stand still as it stops moving southwards each day and begins move to the north. This is the first day of winter as marked by many cultures in the northern hemisphere. Alternately, this is the first day of summer for those folks in the southern hemisphere.

2013 Solstices and Equinoxes
  UT HST
Perihelion Jan 2 00:59UT Jan 1 14:59HST
Spring Equinox Mar 20 11:02UT Mar 20 01:02HST
Summer Solstice Jun 21 05:04UT Jun 20 19:04HST
Apehelion Jul 5 18:59UT Jul 5 08:59HST
Fall Equinox Sep 22 20:44UT Sep 22 10:44HST
Winter Solstice Dec 21 17:11UT Dec 21 07:11HST
 
Source: NASA Sky Calendar

 

Apehelion

Today the Earth is furthest from the Sun, a point called apehelion. We will be about 152,096,000km (94,508,000miles) from the Sun. Compare this to the 147,099,000km (91,403,000miles) we were be at perihelion on January 1st, a difference of about 4,996,000km (3,104,000miles) occurring throughout one orbit.

It may seem odd that we are actually at the furthest for the middle of northern summer, you just have to remember that proximity to the Sun is not the cause of the seasons. The seasons are caused by the axial tilt of the Earth, creating short and long days throughout the year, with a resulting change in the angle and intensity of the sunlight.

2013 Solstices and Equinoxes
  UT HST
Perihelion Jan 2 00:59UT Jan 1 14:59HST
Spring Equinox Mar 20 11:02UT Mar 20 01:02HST
Summer Solstice Jun 21 05:04UT Jun 20 19:04HST
Apehelion Jul 5 18:59UT Jul 5 08:59HST
Fall Equinox Sep 22 20:44UT Sep 22 10:44HST
Winter Solstice Dec 21 17:11UT Dec 21 07:11HST
 
Source: NASA Sky Calendar

 

Perihelion

Today the Earth is closest to the Sun, a point called perihelion. We will be about 147,099,000km (91,403,000miles) from the Sun. Compare this to the 152,096,000km (94,508,000miles) we will be at aphelion on July 4th, a difference of about 4,996,000km (3,104,000miles) occurs throughout one orbit.

It may seem odd that we are actually at the closest for the middle of northern winter, you just have to remember that proximity to the Sun is not the cause of the seasons. The seasons are caused by the axial tilt of the Earth, creating short and long days throughout the year, with a resulting change in the angle and intensity of the sunlight.

2013 Solstices and Equinoxes
  UT HST
Perihelion Jan 2 00:59UT Jan 1 14:59HST
Spring Equinox Mar 20 11:02UT Mar 20 01:02HST
Summer Solstice Jun 21 05:04UT Jun 20 19:04HST
Apehelion Jul 5 18:59UT Jul 5 08:59HST
Fall Equinox Sep 22 20:44UT Sep 22 10:44HST
Winter Solstice Dec 21 17:11UT Dec 21 07:11HST
 
Source: NASA Sky Calendar

 

Apehelion

Today the Earth is furthest from the Sun, a point called apehelion. We will be about 152,098,232km (94,509,459miles) from the Sun. Compare this to the 147,098,290km (91,402,639miles) we were at perihelion on Jan 4th, a difference of about 5,411,169km (3,362,344miles) occurs throughout one orbit.

It may seem odd that we are actually at the furthest for the middle of northern summer, you just have to remember that proximity to the Sun is not the cause of the seasons. The seasons are caused by the axial tilt of the Earth, creating short and long days throughout the year, with a resulting change in the angle and intensity of the sunlight.

2012 Solstices and Equinoxes
  UT HST
Perihelion Jan 5 03:59UT Jan 4 17:59HST
Spring Equinox Mar 20 05:14UT Mar 19 19:14HST
Summer Solstice Jun 20 23:09UT Jun 20 13:09HST
Apehelion Jul 4 23:59UT Jul 4 13:59HST
Fall Equinox Sep 22 14:49UT Sep 22 04:49HST
Winter Solstice Dec 21 11:12UT Dec 21 01:12HST
 
Source: USNO Data Services Website and the NASA Sky Calendar