Hot answers tagged

30 votes
Accepted

Can Pluto be seen with the naked eye from Neptune when Pluto and Neptune are closest?

No, it cannot. Far from it. The closest approach between both planets is roughly 16 AU due to the 3:2 orbit resonance. Pluto will even then be a tiny dot among many with a brightness around 14 mag. ...
user avatar
  • 10.7k
25 votes

Why is Neptune a darker blue than Uranus?

This is an intriguing question, with a solution suggested by the Irwin et al. (2022; arXiv:2201.04516) paper that inspired the YouTube, NewScientist, ScienceAlert, Phys.org, etc. coverage of the past ...
user avatar
  • 1,764
18 votes
Accepted

Could Neptune be viewed with the naked eye from Uranus?

According to https://arxiv.org/pdf/1808.01973.pdf, the magnitude of Neptune follows the relationship (formula 17, page 25): $ V = 5 \log_{10} (rd) - 7.00 + 7.944 \times 10^{-3} α + 9.617 \times 10^{-5}...
user avatar
17 votes

How am I supposed to locate the planets Uranus and Neptune with a 70 mm f/5.7 refractor?

Right now you won't. Both are on the "wrong" side of the sun and so not easily observable from Earth. At the moment (early 2020s) they are in the constellation of Aries and Pices which are ...
user avatar
  • 87.5k
16 votes

Why does Neptune only have one major moon?

It seems possible that Neptune once had a system of moons similar to other outer planets. However Triton, a Kuiper belt object was captured by Neptune, and this disrupted the existing moons. It would ...
user avatar
  • 87.5k
14 votes

Can Pluto be seen with the naked eye from Neptune when Pluto and Neptune are closest?

According to the NASA Pluto fact sheet, the brightest that Pluto gets is an apparent visual magnitude of 13.65 when it is 28.6 au from the Earth and (presumably) about 29.6 au from the Sun. To work ...
user avatar
  • 113k
14 votes

Could Neptune be viewed with the naked eye from Uranus?

Supplementary answer supporting @PierrePaquette thorough and well-source answer: I tried the nice new JPL Horizons interface and fired up Excel which I haven't used in a long time. For years 1800 to ...
user avatar
  • 31.6k
13 votes

Have there been successful attempts at spotting Neptune with the naked eye?

Well, having seen Neptune and identifying Neptune are two totally different things. Let's tackle this one step at a time. Your link says: From these observations it would appear that, if seen upon ...
user avatar
10 votes
Accepted

How fast is Neptune getting brighter? When was was this first noticed and reported?

TL;DR: There was apparent 11% increase of Neptune brightness during 1980 and 2000. This could be due to multiple reasons. Recent observation suggested the reason to be change in the amount and ...
user avatar
  • 3,226
9 votes
Accepted

Why was Neptune rather than Uranus chosen as an archetype?

NASA distinguishes four types of exoplanets: Gas Giant, Super-Earth, Neptune-like, and Terrestrial. The question asks why ice planets termed "Neptune-like" and not "Uranus-like". ...
user avatar
  • 5,284
8 votes
Accepted

Why do Uranus and Neptune have more methane than Jupiter and Saturn?

Why does Uranus and Neptune have more methane than Jupiter and Saturn? It's a combination of equations of state (EOS), serpentinization, and mixing (rotational and convective) that favors a ...
user avatar
  • 2,532
8 votes

Do tides occur on planets like Neptune, having water?

There will be tides, but they will be not very large. It's pretty easy to get a good estimate of their size. There are two things that control tides on Earth and both will be present anywhere else: ...
user avatar
  • 7,370
8 votes

Could Neptune be viewed with the naked eye from Uranus?

The brightness of a Solar System object, seen in reflected light, depends on how far it is from the Sun, $d_s$, and how far away it is from the observer, $d_o$, (and the angles between them). Both ...
user avatar
  • 113k
7 votes

Do tides occur on planets like Neptune, having water?

Neptune's largest moon, Triton, is about a third the mass of Earth's moon, and roughly the same distance away from its primary, so it will indeed have noticeable tidal effect on Neptune's atmosphere ...
user avatar
7 votes

Why is Neptune a darker blue than Uranus?

Tl:DR: According to a team led by planetary physicist Patrick Irwin of the University of Oxford in the UK, an extended layer of haze dilutes the hue of Uranus, resulting in a paler color compared to ...
user avatar
  • 3,226
5 votes
Accepted

Why is the eccentricity of Triton so low?

Tidal circularization is indeed a plausible mechanism for why Triton's orbital eccentricity is so low, and I believe it is in fact the prevailing theory, at the moment. In short, tidal forces from ...
user avatar
  • 33.7k
5 votes
Accepted

Can Pluto and Neptune collide anytime in future?

It's hard to find a good 2 dimensional representation, but Pluto and Neptune's orbits don't actually cross. In fact, the orbits (not the planets but the orbits) never get within 100 million miles (...
user avatar
  • 22.9k
5 votes

Diamonds in Neptune?

People have demonstrated high-pressure diamond formation using laser-driven shocks, much in line with the original idea. The diamond rain idea seems to be doing well (popular science article about it, ...
user avatar
5 votes

Aren't there any rock or similar firm material on/in the gas giant planets?

The inside of a giant planet is not like regular gas. First of all, it is hot. You are away of how it gets hot inside the Earth (causing volcanos). It is also hot inside Jupiter, but since Jupiter ...
user avatar
  • 87.5k
5 votes
Accepted

Dates of Passage of Neptune at Aphelion and Perihelion

The last perihelion passage of the Neptune system barycentre relative to the Solar System barycentre (SSB) was at 1881-Feb-02 10:00 TDB. Here's a plot (courtesy of JPL Horizons) of the distance from ...
user avatar
  • 8,862
4 votes
Accepted

How did VLT's adaptive optics obtain this resolution for Neptune? Is it really working in visible wavelengths?

It is an image taken with the new narrow field mode of the MUSE instrument using the GALACSI Adaptive optics module on a single (UT4) VLT telescope using laser guide stars. I am having a great deal ...
user avatar
  • 113k
4 votes

Before Voyager 2, what were the highest quality photos of Uranus and Neptune?

As per the books referred to in comments: Both planets could be resolved as a disk, but no surface features could be observed on either. Spectrograms had been taken, so the general colour of the ...
user avatar
  • 87.5k
4 votes
Accepted

Does the lower mass of Uranus suggest it swapped position with Neptune?

The Nice model of solar system evolution proposes that both Uranus and Neptune migrated outward from their original orbits due to numerous encounters with planetesimals, stimulated by a temporary 2:1 ...
user avatar
  • 16.5k
4 votes

Neptune's Internal Heat Source

Neptune and Uranus have estimated core temperatures of 7273 K and 5255 K respectively. Uranus and Neptune however likely do not have liquid water oceans. The combination of pressure and temperature on ...
user avatar
4 votes

Can Pluto be seen with the naked eye from Neptune when Pluto and Neptune are closest?

That's great question! ... I'm just thinking that just for comparison, Pluto is roughly 70% the diameter of our Moon and Pluto would be far away from Neptune than the Moon is from Earth. Moon is also ...
user avatar
4 votes
Accepted

Why is the magnetic axis of Uranus and Neptune off center?

Disclaimer: This answer is inspired by Magnetic fields of Uranus and Neptune: Metallic fluid hydrogen by Nellis [2017], who explains the center offset of the ice-giants' magnetic fields by contrasting ...
user avatar
  • 13.6k

Only top scored, non community-wiki answers of a minimum length are eligible