About the image. Drawn almost black, with a faint red glow from its own heat. The darkness is measured; the reasons for it, and any banding, are not.
31×as wide as our Sun looks from Earth
1 000×the light Earth gets
Likely tidally locked: the star stays putNo ground: the view from the cloud tops
The sky from TrES-2b
TrES-2 would look 31× as wide as the Sun does from Earth, and the planet gets 1 000× as much light as Earth gets.
Its colour comes from its surface temperature of 5 850 K (5 580 °C); the Sun's is about 5 772 K (5 500 °C).
TrES-2b is likely tidally locked: one side always faces the star.
There are no sunrises. Where you stand decides where the star hangs, overhead on the day side, low at the edge, gone on the night side.
Apparent size = star radius ÷ orbit; light = size² × (temperature ÷ 5 772 K)⁴. Both from the values on this page. The landscape is imagined.
TrES-2b was discovered in 2006, a hot Jupiter circling a Sun-like star every two and a half days. It became famous five years later, when David Kipping and David Spiegel used Kepler’s extremely precise brightness measurements to work out how much light the planet reflects.
Blacker than coal
The answer was: almost none. The true reflectivity is estimated at less than 1%, with the best-fitting model giving about 0.04%. The planet reflects less of the light that strikes it than coal or black acrylic paint. It is the darkest planet known.
It is not completely invisible. The planet is hot, with a night side estimated at almost 1 900 K (1 630 °C), and it gives off a dim reddish glow of its own.
Why so dark?
Nobody knows for certain. Jupiter is bright because of its high, reflective clouds. TrES-2b is too hot for such clouds to form. Something in its atmosphere must also be soaking up light. Vaporised sodium and potassium, or gaseous titanium oxide, have been proposed, but none of them explains the darkness fully.
It is a good reminder of how strange exoplanets can be. Close up, this world would look less like a planet and more like a hole in the sky.
Its orbit, to scale
TrES-2b goes around once every 2.5 days, at 0.03568 AU from its star. The whole view is tiny on Solar System scale: Mercury orbits the Sun about 11 times farther out than the outermost orbit shown here.
TrES-2b: equilibrium temperature. Logarithmic scale from 100 K to 10 000 K. Reference values: NASA, IAU.
How long to get there?
TrES-2b is about 702 light-years away.
Light299 792 km/s702 years
Breakthrough Starshotplanned light sail, 20% of light speed3 510 years
Parker Solar Probefastest spacecraft so far, 192 km/s1.1 million years
Voyager 1leaving the Solar System, 17 km/s12.4 million years
At Voyager 1's speed the trip would take about 154 746 human lifetimes of 80 years. Bars are on a logarithmic scale. Speeds: NASA, Breakthrough Initiatives.
Your weight on TrES-2b
On TrES-2b
Gravity there is about 2.04× Earth's, at the cloud tops; there is no surface. Calculated from the measured mass and radius.
Gallery
Artist's impressions rendered from the same model as the view at the top of this page.
Timeline
2006Discovered by the Trans-Atlantic Exoplanet Survey.
2011Kepler data show it reflects less than 1% of the light that hits it.
2015Its night side is estimated at nearly 1 900 K (1 630 °C).
Questions people ask
What is the darkest planet?
TrES-2b. It reflects less than 1% of the light that reaches it, less than coal or black acrylic paint.
Why is TrES-2b so dark?
It is too hot for reflective clouds, and something in its atmosphere absorbs light. Vaporised sodium, potassium or titanium oxide have been suggested, but the cause is not settled.
Does TrES-2b glow?
Faintly. It is hot enough to give off a dim red glow of its own.