Binding of Isaac: Rebirth Wiki
Solar   System
Table dividing line 1.png
Challenge Number
Available Rooms
Item Pool Treasure Room.png: no          Item Pool Shop.png: yes
Boss Mom's Heart portrait.png
Unlock Method

Solar System Defeat Mom's Heart 3 times

Solar System is challenge #6. Isaac starts this challenge with Distant Admiration Distant Admiration, Forever Alone Forever Alone, Halo of Flies Halo of Flies, and Transcendence Transcendence. Isaac will also be blindfolded. The goal is to defeat Mom's Heart Mom's Heart/ It Lives It Lives. This Challenge is available after unlocking Transcendence.


  • As Isaac is blindfolded, Isaac cannot use tears, and must rely entirely on Distant Admiration, Forever Alone, and bombs to deal damage.


  • Because Isaac starts with 3 Fly items, he will also begin the challenge as Beelzebub Beelzebub. This allows Isaac to amass a large number of friendly flies on the Basement floors.
  • The orbiting attack flies can be quite powerful, especially Distant Admiration when used properly. This will require optimization of Isaac's movement to maneuver into position to deal damage, as the flies are constantly moving, and avoid damage simultaneously.
    • Added in Afterbirth †Duct Tape Duct Tape can fix the position of the flies around Isaac, somewhat alleviating this.
  • Enemies that explode on death should only be targeted with Forever Alone, as destroying them with Distant Admiration will result in Isaac getting caught in their explosions.
  • Shops can carry BFFS! BFFS! and Hive Mind Hive Mind, the former of which affects the damage of the orbiting attack flies and the latter of which affects the damage of the blue flies spawned from Beelzebub as well as the size of the orbiting attack flies.
  • Broken Watch Broken Watch and Stop Watch Stop Watch are good items to buy since they slow enemies down, although caution should be exercised with Broken Watch.
  • Obtaining Gnawed Leaf Gnawed Leaf makes the challenge trivial as Isaac's orbiting flies still deal damage while Isaac is invulnerable. Obtaining it is highly unlikely, since there are no Treasure Room Treasure Rooms present.
  • Obtaining Ball of Bandages Ball of Bandages or Cube of Meat Cube of Meat grants a full circle of projectile-blocking orbitals around Isaac.
    • Collecting two Cubes of Meat grants a tear-firing familiar that is not affected by the blindfold.
    • Obtaining Book of Revelations Book of Revelations makes The Harbingers easier to find, allowing Cube of Meat and Ball of Bandages to be amassed more easily.
  • Removed in Afterbirth It is not advised to reshuffle Isaac's items. As this will not remove Isaac's Blindfolded status, it is possible to reroll items in such a way that Isaac's orbitals are rerolled into useless items, thus making the run impossible to complete.
  • Obtaining the Rune of Algiz Rune of Algiz, Chaos Card Chaos Card, A Card Against Humanity A Card Against Humanity, or The Bible The Bible can make killing Mom Mom and Mom's Heart Mom's Heart/ It Lives It Lives much easier.
  • Devil Room Devil Room deals such as Brimstone Brimstone, Added in AfterbirthMaw of the Void Maw of the Void, and Mom's Knife Mom's Knife will be ineffective due to Isaac's blindfold.
    • Added in RepentanceMaw of the Void Maw of the Void now functions despite the Blindfolded status, making this a very valuable item for the challenge.
  • Removed in AfterbirthThe Boomerang The Boomerang is a useful purchase from the shop as it has a chance to freeze enemies, allowing Isaac to safely use the attack flies against them for the duration of the freeze.
  • Transcendence and other flight items are useless in this challenge as the Beelzebub Beelzebub transformation grants flight by default.
  • Obtaining Bob's Brain Bob's Brain can be handy for defeating bosses, due to its damage and poison effect. It can also be used to break poop or golden poop to gain health, coins, or bombs.
  • Added in Afterbirth †Extension Cord Extension Cord electrifies the orbiting flies, dealing extra damage and allowing Isaac to destroy Fire Place Fire Places and Poop Poops.
  • Added in AfterbirthBlack Powder Black Powder helps damage non-flying enemies and bosses.
    • Added in Repentance Black Powder is now effective on all enemies and bosses, making it a reliable source of damage without the precision required to deal damage using Isaac's orbiting flies, provided there is room to draw closed shapes.
  • Added in AfterbirthIncubus Incubus acts as a replacement for Isaac's tears, thus indirectly removing Isaac's Blindfolded status.
  • Added in RepentanceRevelation Revelation can charge and fire regardless of the Blindfolded status, providing Isaac with an easy way to deal damage.
  • Added in Afterbirth †Pause Pause can be used to great effect as it can permanently stop the movement of all enemies in every other room. Pairing this with items that help with recharging activated items, mainly 9 Volt 9 Volt, can guarantee victory.
  • It is heavily advised not to use Added in Afterbirth †Sacrificial Altar Sacrificial Altar, as it removes both of Isaac's damaging orbital familiars. If no alternative source of damage has been obtained by then, or rewarded by Sacrificial Altar itself, the run will be rendered impossible.

Unlockable achievements[]


  • The challenge is a reference to the real-world Solar System; Isaac represents the Sun and his flies represent planets.